- vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 43342] GRB 260706A : GRANDMA Upper limits
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45128 SUBJECT: GRB 260706A : GRANDMA Upper limits DATE: 26/07/09 17:52:30 GMT FROM: antier(a)ijclab.in2p3.fr K. Agabi (OCA), A. Simon (TShNU of Kyiv), L. Wyrzykowski (Uni. Warsaw/NCBJ), A. Guštin (UNG School of Science, GoChile), J. Hambsch (VVS, GEOS, BAV), S. Antier (IJCLAB), M. Pillas (IAP), L. Abe (OCA), T T. Guillot (OCA). X. Sheng (QUB), P. Gokuldass (ERAU), E. Elhosseiny (KAO), O. Sokoliuk (UKyiv), Y. Rajabov (UBAI), Z. Maksut NU), E. Jehin (U of Liège), M. Ferrais (U of Liège) on behalf of GRANDMA collaboration: We observed the field of GRB 260706A detected by SVOM/ECLAIRs (GCN 45089), SVOM/GRM and Fermi-GBM (GCN 45088) and its counterpart detected by EP-FXT (GCN 45097, GCN 45114). The observations started at 20:30:00 UTC on the 6 of July 2026, 4.3 post ECLAIRs T0 with ASTEP and last about 1 day in all the network. We didn't detect any optical counterpart at the EP location (and near by) with GRANDMA, using 0.4m GoT1 telescope of University of Nova Gorica hosted at El Sauce Observatory in Chile, 0.6m TRAPPIST-South, 14" telescope at Franz-Josef Hambsch's Remote Observatory Atacama Dessert (ROAD) in Chile, ASTEP-50cm at Concordia, 1m LCO-SAAO telescope in South Africa with observatory in multiple epochs and filters. We reported our upper limit in the public ACME service Skyportal/ICARE https://skyportal-icare.ijclab.in2p3.fr/source/GCN-260706_161221. To access, one simply needs to create an account using your ORCID id. Our upper limit are coherent with REM (GCN 45100), LCO-1m (GCN 45098), and SVOM/VT (GCN 45113). The data were reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the Sloan filters were calibrated using the PanSTARRS DR1 catalog. Images obtained with the Johnson-Cousins filters were calibrated using the Gaia DR3 Synphot catalog. The observations are performed under the P7 campaign of GRANDMA to monitor SVOM alerts and LSST alerts from explosive fast transients filtered by BOOM/Babamul and FINK. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Astrophysics Center for Multimessenger studies in Europe is supported Skyportal/ICARE (contact camille.douzet(a)ijclab.in2p3.fr, skyportal.io). View this GCN Circular online at https://gcn.nasa.gov/circulars/45128. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43341] GRB 260708A: Kilonova-Catcher optical afterglow detection
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45127 SUBJECT: GRB 260708A: Kilonova-Catcher optical afterglow detection DATE: 26/07/09 17:01:32 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> M. Freeberg (KNC), D. Turpin (CEA-Saclay/Irfu), C. Andrade(UMN), S. Antier (IJCLab), M. Coughlin (UMN),S. Karpov (FZU), P. Hello (IJCLAB), M. Pillas (IAP) on behalf of the GRANDMA/Kilonova-Catcher collaboration: We observed the field of GRB 260708A detected by Fermi/GBM (Fermi GBM team, GCN 45115; GCN 45124) and Fermi/LAT (Holzmann Airasca et al., GCN 45117) with the GRANDMA citizen science project Kilonova-catcher (KNC). Our observations were performed with a iTtelescope T30 located at Siding Spring Observatory operated by M. Freeberg. Our observations started at TGRB+1.17 days and were taken with the Johnson/Cousins R filter. In our stacked frames, we clearly detect the optical counterpart reported by MASTER (Shilova et al., GCN 45123). We report part of our follow-up results in the table below : | Tmid-TGRB (days) | Exp (s) | Filter | Magnitude | Instrument | | ------------ | ------------ |------------ |------------ |------------ | | 1.18 | 3 x 300s | R (Vega) | 18.93 +/- 0.14 | iT30 | Given the significant fading behavior compared to the previous MASTER epoch, we considered this optical candidate is the optical afterglow of the energetic burst GRB 260708A. Further observations are ongoing. All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the Johnson-cousins filters were calibrated using the GAIA DR3 synphot catalog. We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023). GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/) View this GCN Circular online at https://gcn.nasa.gov/circulars/45127. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43340] GRB 260708A: GECAM-B observation of a burst
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45126 SUBJECT: GRB 260708A: GECAM-B observation of a burst DATE: 26/07/09 16:35:09 GMT FROM: renyz16607(a)163.com Yang-Zhao Ren, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-B was triggered in-flight by GRB 260708A, at 2026-07-08T10:11:17.650 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45115), and Fermi/LAT (Fermi LAT team, GCN #45117). According to the GECAM-B light curves in about 70-6000 keV, this burst mainly consists of multiple pulses with a duration (T90) of 46.5 +5.0/-6.5 s. The GECAM-B light curve can be found here: https://www.bursthub.cn//admin/static/gecambgrb260708A.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). View this GCN Circular online at https://gcn.nasa.gov/circulars/45126. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43339] IceCube-260708A: One candidate from the Zwicky Transient Facility
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45125 SUBJECT: IceCube-260708A: One candidate from the Zwicky Transient Facility DATE: 26/07/09 16:21:49 GMT FROM: Robert David Stein at JSI <rdstein(a)umd.edu> Robert Stein (JSI), Tomas Ahumada (Noirlab), Mansi Kasliwal (Caltech), Jesper Sollerman (Stockholm), Cristobal Zilleruelo Cañas (DESY), Jannis Necker (Leiden University), Akshay Eranhalodi (DESY), and Anna Franckowiak (Ruhr University Bochum) report, On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-260708A (Zegarelli et. al, GCN 45120) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2026-07-09 08:12 UTC, approximately 14.9 hours after event time. We covered 23.8% (0.2 sq deg) of the reported localization region at least twice. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019) . We are left with the following high-significance transient candidate by our pipeline, lying within the 90.0% localization of the skymap. +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF26abfurzw | AT2026kuv | 292.8653948 | -15.1344488 | r | 20.11 | 0.07 | +--------------------------------------------------------------------------------+ ZTF26abfurzw/AT 2026kuv was discovered by GOTO on 2026-04-20, and reported to TNS. ATLAS forced photometry reveals a lightcurve rising since discovery, later peaking at 17.4 mag at the beginning of May. The source has since slowly faded. The source was detected in our ZTF ToO observations, and the photometry confirms that the source is now very red (g-r = 1) and faded substantially from peak. There were no previous ZTF survey detections, because the source lies in a chip gap for the survey footprint. The photometric properties (rise, fade, and late-time colour) of AT 2026kuv appear consistent with a supernova. Neutrino emission in a post-peak supernova would be plausible if there were CSM interaction in the source. We encourage spectroscopic observations of this source to confirm its nature, and to search for evidence of CSM interaction. Further monitoring of this field will continue as part of the ZTF neutrino follow-up program (Stein et al. 2023), and we are planning additional follow-up of AT 2026kuv. ZTF and GROWTH are worldwide collaborations comprising Caltech/IPAC, USA; University of Maryland, USA; University of California, Berkeley, USA; Cornell University, USA; Drexel University, USA; University of North Carolina at Chapel Hill, USA; Institute of Science and Technology, Austria; National Central University, Taiwan; OKC, Sweden; DZA, Germany. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf ). View this GCN Circular online at https://gcn.nasa.gov/circulars/45125. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43338] GRB 260708A: Fermi-GBM observation
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45124 SUBJECT: GRB 260708A: Fermi-GBM observation DATE: 26/07/09 15:29:24 GMT FROM: Christian Malacaria at INAF-OAR <cmalacaria.astro(a)gmail.com> C. Malacaria (INAF-OAR) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 10:11:16.89 UT on 08 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260708A (trigger 805198281/260708424). The Final real-time localization was reported in GCN 45115. Fermi-LAT also detected GRB 260708A (GCN 45117). The GBM light curve displays a sharp peak with a duration (T90) of about 62 s (50-300 keV). The time-averaged spectrum from T0+0.5 to T0+49.7 s is best fit by a power law function with a power law index of -1.86 +/- 0.01 . The event fluence (10-1000 keV) in this time interval is (2.14 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.5 s in the 10-1000 keV band is 19.6 +/- 0.5 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/45124. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43337] Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45123 SUBJECT: Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection DATE: 26/07/09 10:23:14 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> M.Shilova, K.Zhirkov, V.Lipunov, A.Kuznetsov, P.Balanutsa, G.Antipov, I.Panchenko, N.Tiurina, Ya.Kechin, E.Gorbovskoy, V.Senik, A.Chasovnikov, V.Topolev,D.Vlasenko,A.Sankovich, I.Gorbunov, V.Fedorova, A.Telnova (Lomonosov MSU), F.Podesta, M.J. Segura, C.Francile, R.Podesta, E. Gonzalez (OAFA, SJNU), D.Buckley (SAAO), A.Sosnovskij (CrAO RAS), N.Budnev, O.Gress (ISU), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A. Gabovich (Blagoveschensk Educational StateUniversity) R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez,J.Martinez,A.R.Corella, J.Tanori, L. Villalobos, L.H.Rodriguez (INAOE, Guillermo Haro AstrophysicsObservatory) MASTER-OAFA and MASTER-SAAO robotic telescopes of MASTER Global Robotic Net [1-4] was pointed to the Fermi LAT GRB 260708A (Holzmann Airasca et al. GCN 45117, trigger 2026-07-08 10:11:16.89 UT, RA, Dec = 225.61, -44.07 +-0.27 (J2000)) at 2026-07-08 22:40:00 UT (Lipunov et al. 45119). There is optical counterpart of GRB 260708A MASTER OT J150237.02-435307.7 https://www.wis-tns.org/object/2026stf discovered by MASTER auto-detection system [1-4] at 2026-07-08 22:42:34.272UT with unfiltere m~17.6m. The typical light curve points to GRB source. spectral observations is required. [1] Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L [2] Lipunov et al. 2022, Universe, Vol. 8(5), id.271 [3] Lipunov et a. 2019, ARep, vol.63, 293 [4] Lipunov et al. 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics,Lomonosov MSU PRESS, 591pp. http://www.pereplet.ru/lipunov/625.html#625 View this GCN Circular online at https://gcn.nasa.gov/circulars/45123. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43336] IceCube Alert 260709A: Global MASTER-Net observations report
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45122 SUBJECT: IceCube Alert 260709A: Global MASTER-Net observations report DATE: 26/07/09 01:40:15 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the IceCube Alert 260709A (trigger No 7869742,19h 31m 14.40s , -15d 10m 12.0s, R=0.47) errorbox 26953 sec after notice time and 27118 sec after trigger time at 2026-07-09 00:49:40 UT, with upper limit up to 19.4 mag. The observations began at zenith distance = 59 deg. The sun altitude is -38.3 deg. The galactic latitude b = -16 deg., longitude l = 24 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3421037 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 27148 | 2026-07-09 00:49:40 | MASTER-OAFA | (19h 30m 06.32s , -15d 10m 17.3s) | C | 60 | 16.9 | 27208 | 2026-07-09 00:49:40 | MASTER-OAFA | (19h 30m 06.31s , -15d 10m 17.2s) | C | 180 | 17.4 | Coadd 27228 | 2026-07-09 00:51:00 | MASTER-OAFA | (19h 30m 06.41s , -15d 11m 45.7s) | C | 60 | 17.0 | 27305 | 2026-07-09 00:52:17 | MASTER-OAFA | (19h 30m 09.68s , -15d 10m 37.9s) | C | 60 | 17.4 | 27402 | 2026-07-09 00:53:54 | MASTER-OAFA | (19h 30m 03.99s , -15d 11m 03.0s) | C | 60 | 18.0 | 27462 | 2026-07-09 00:53:54 | MASTER-OAFA | (19h 30m 03.99s , -15d 11m 03.0s) | C | 180 | 18.7 | Coadd 27477 | 2026-07-09 00:55:09 | MASTER-OAFA | (19h 30m 04.40s , -15d 09m 58.9s) | C | 60 | 18.5 | 27553 | 2026-07-09 00:56:25 | MASTER-OAFA | (19h 30m 08.71s , -15d 10m 56.6s) | C | 60 | 18.9 | 27631 | 2026-07-09 00:57:43 | MASTER-OAFA | (19h 30m 02.58s , -15d 11m 52.6s) | C | 60 | 19.0 | 27691 | 2026-07-09 00:57:43 | MASTER-OAFA | (19h 30m 02.58s , -15d 11m 52.6s) | C | 180 | 19.4 | Coadd 27710 | 2026-07-09 00:59:02 | MASTER-OAFA | (19h 30m 09.79s , -15d 11m 21.7s) | C | 60 | 19.0 | 27785 | 2026-07-09 01:00:17 | MASTER-OAFA | (19h 30m 06.55s , -15d 09m 52.2s) | C | 60 | 19.0 | 27894 | 2026-07-09 01:01:36 | MASTER-OAFA | (19h 30m 06.54s , -15d 11m 32.2s) | C | 120 | 18.9 | 28014 | 2026-07-09 01:01:36 | MASTER-OAFA | (19h 30m 06.54s , -15d 11m 32.2s) | C | 360 | 19.3 | Coadd 28033 | 2026-07-09 01:03:55 | MASTER-OAFA | (19h 30m 10.13s , -15d 10m 05.9s) | C | 120 | 18.9 | 28170 | 2026-07-09 01:06:12 | MASTER-OAFA | (19h 30m 03.95s , -15d 10m 29.8s) | C | 120 | 19.0 | 28416 | 2026-07-09 01:10:18 | MASTER-OAFA | (19h 30m 09.10s , -15d 10m 24.0s) | C | 120 | 18.8 | 28536 | 2026-07-09 01:10:18 | MASTER-OAFA | (19h 30m 09.10s , -15d 10m 24.0s) | C | 360 | 19.1 | Coadd 28551 | 2026-07-09 01:12:33 | MASTER-OAFA | (19h 30m 02.60s , -15d 11m 18.1s) | C | 120 | 18.6 | 28684 | 2026-07-09 01:14:46 | MASTER-OAFA | (19h 30m 09.44s , -15d 11m 01.1s) | C | 120 | 18.7 | 28823 | 2026-07-09 01:17:05 | MASTER-OAFA | (19h 30m 06.57s , -15d 09m 18.7s) | C | 120 | 18.7 | 28959 | 2026-07-09 01:19:21 | MASTER-OAFA | (19h 30m 06.54s , -15d 10m 33.6s) | C | 120 | 18.9 | 29098 | 2026-07-09 01:21:40 | MASTER-OAFA | (19h 30m 09.79s , -15d 08m 58.3s) | C | 120 | 19.1 | 29235 | 2026-07-09 01:23:57 | MASTER-OAFA | (19h 30m 03.25s , -15d 09m 51.7s) | C | 120 | 19.2 | 29373 | 2026-07-09 01:26:15 | MASTER-OAFA | (19h 30m 02.88s , -15d 08m 46.5s) | C | 120 | 19.3 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45122. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43335] GRB 260709A: Fermi GBM Final Real-time Localization
by GCN Circulars 09 Jul '26

09 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45121 SUBJECT: GRB 260709A: Fermi GBM Final Real-time Localization DATE: 26/07/09 01:18:22 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 01:07:32 UT on 9 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260709A (trigger 805252057.543312 / 260709047). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 84.1, Dec = 74.0 (J2000 degrees, equivalent to J2000 05h 36m, 74d 00'), with a statistical uncertainty of 4.0 degrees. The angle from the Fermi LAT boresight is 106.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260709047/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260709047/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260709047/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45121. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43334] IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45120 SUBJECT: IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 26/07/08 23:09:54 GMT FROM: A. Zegarelli at Ruhr University Bochum <azegarelli(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 26-07-08 at 17:17:42.55 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_GOLD alert stream. Documentation regarding the alert streams and their astrophysical purity can be found here: https://gcn.nasa.gov/missions/icecube. This alert has an estimated false alarm rate of 0.1472 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/142827_7869742.amon) more sophisticated reconstruction algorithms have been applied offline. Some computational anomalies are observed in the primary offline reconstruction algorithm for this event, so the directional reconstruction results from the alternative offline algorithm are included in this event while these anomalies are investigated. With this alternative algorithm, the direction is refined to: Date: 26-07-08 Time: 17:17:42.55 UT RA: 292.81 (+0.48/-0.47 deg 90% PSF containment) J2000 Dec: -15.17 (+0.44/-0.48 deg 90% PSF containment) J2000 As announced in GCN Circular 43419 (https://gcn.nasa.gov/circulars/43419) IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'. The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts. The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX, where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link is provided through the GCN schema distributed via Kafka. Detailed documentation describing the alert distribution, schemas, and probability maps is available at: https://gcn.nasa.gov/missions/icecube. No known gamma-ray sources listed in the Fermi LAT 16-year Source List (FL16Y) are located within the 90% uncertainty region of this event. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu View this GCN Circular online at https://gcn.nasa.gov/circulars/45120. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43333] LAT GRB260708.42: Global MASTER-Net observations report
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45119 SUBJECT: LAT GRB260708.42: Global MASTER-Net observations report DATE: 26/07/08 22:55:59 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the LAT GRB260708.42 (trigger No 805198281,15h 02m 26.40s , -44d 04m 12.0s, R=0.369833) errorbox 23412 sec after notice time and 44923 sec after trigger time at 2026-07-08 22:40:00 UT, with upper limit up to 18.6 mag. Observations started at twilight. The observations began at zenith distance = 25 deg. The sun altitude is -11.4 deg. The galactic latitude b = 12 deg., longitude l = 327 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3420593 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 44954 | 2026-07-08 22:40:00 | MASTER-OAFA | (15h 01m 59.54s , -43d 52m 20.2s) | C | 60 | 17.8 | 45029 | 2026-07-08 22:41:16 | MASTER-OAFA | (15h 02m 05.06s , -43d 53m 19.4s) | C | 60 | 18.1 | 45108 | 2026-07-08 22:42:34 | MASTER-OAFA | (15h 02m 00.49s , -43d 54m 17.7s) | C | 60 | 18.6 | 45182 | 2026-07-08 22:43:49 | MASTER-OAFA | (15h 02m 05.32s , -43d 54m 07.3s) | C | 60 | 18.5 | 45255 | 2026-07-08 22:45:02 | MASTER-OAFA | (15h 02m 02.92s , -43d 52m 33.7s) | C | 60 | 17.7 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45119. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43332] GRB260708B: MAXI/GSC detection
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45118 SUBJECT: GRB260708B: MAXI/GSC detection DATE: 26/07/08 18:52:03 GMT FROM: nakajima.motoki(a)nihon-u.ac.jp M. Nakajima, H. Negoro, K. Saito, T. Yokoyama, M. Wada (Nihon U.), T. Mihara, T. Tamagawa, N. Kawai, M. Matsuoka (RIKEN), T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, H. Hiramatsu, A. Yoshida (AGU), Y. Tsuboi, Y. Ishihara, H. Ogaki (Chuo U.), M. Shidatsu, C. Kang, M. Uenishi, T. Usuki, S. Yatsuzuka, H. Aoe (Ehime U.), I. Takahashi, Y. Yatsu (Science Tokyo), S. Nakahira, S. Ueno, H. Tomida, M. Kurihara (JAXA), Y. Ueda, K. Fujiwara, S. Kobayashi (Kyoto U.), M. Yamauchi, M. Nishio, C. Hiraizumi (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Sugizaki (Kanazawa U.), W. Iwakiri (Chiba U.), T. Kawamuro (Osaka U.), S. Yamada (Tohoku U), S. Ogawa (TUS) report on behalf of the MAXI team: The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 16:43:12 UT on July 8 2026. Assuming that the source flux was constant over the transit, we obtain the source position at (R.A., Dec) = (342.139 deg, -3.776 deg) = (22 48 33, -03 46 33) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.22 deg and 0.18 deg, respectively. The roll angle of long axis from the north direction is 167.0 deg counterclockwise. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The X-ray flux averaged over the scan was 172 +- 25 mCrab (4.0-10.0keV, 1 sigma error). Without assumptions on the source constancy, we obtain a rectangular error box for the transient source with the following corners: (341.215, -2.825) deg = (22 44 51, -02 49 30) (J2000) (340.981, -3.128) deg = (22 43 55, -03 07 40) (J2000) (342.971, -4.662) deg = (22 51 53, -04 39 43) (J2000) (343.205, -4.358) deg = (22 52 49, -04 21 28) (J2000) There was no significant excess flux in the previous transit at 15:10 UT and in the next transit at 18:16 UT with an upper limit of 20 mCrab for each. View this GCN Circular online at https://gcn.nasa.gov/circulars/45118. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43331] GRB 260708A: Fermi-LAT detection
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45117 SUBJECT: GRB 260708A: Fermi-LAT detection DATE: 26/07/08 17:20:47 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> A. Holzmann Airasca (UniTrento and INFN Bari), D. Depalo (Politecnico and INFN Bari) and P. Loizzo (UniTrento and INFN Bari) report on behalf of the Fermi-LAT collaboration: At 10:11:16.89 UT on July 8th, 2026, Fermi-LAT detected high-energy emission from GRB 260708A, which was also detected by Fermi-GBM (trigger 805198281/260708424, GCN #45115). The best LAT on-ground location is found to be RA, Dec = 225.61, -44.07 (J2000) with an error radius of 0.27 deg (90 % containment, statistical error only). This was 43 deg from the LAT boresight at the time of the trigger. The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the trigger with high significance. The photon flux above 100 MeV in the time interval 0 - 400 s after the GBM trigger is (1.9 ± 0.4)E-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.5 ± 0.3. The highest energy photon has an energy of 2.1 GeV and occurs at 65.8 s after trigger time. The Fermi-LAT point of contact for this burst is Pierpaolo Loizzo (pierpaolo.loizzo(a)ba.infn.it) The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/45117. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43330] GRB 260705B: SVOM/GRM observation
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45116 SUBJECT: GRB 260705B: SVOM/GRM observation DATE: 26/07/08 16:19:53 GMT FROM: Xinghao Luo at IHEP <2952704891(a)qq.com> SVOM/GRM team: Xing-Hao Luo, Chen-Wei Wang, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Nicolas Dagoneau (CEA) Report on behalf of the SVOM team: SVOM/GRM was triggered on-ground by GRB 260705B at 2026-07-05T22:46:39.000 UTC (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45081). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple pulses with a T90 of 99 +12/-9 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260705B.png In addition, the position of this burst, as determined by Fermi/GBM (RA=68.5 , DEC=-30.8, with a statistical uncertainty of 3.0 degrees, Fermi GBM team, GCN #5081), is located at about 74 degrees form the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-24 to T0+75 s is best fitted by a power law function. The power law index is -1.84 +/-0.06. The event fluence (10-1000keV) in this time interval is (1.11 +0.19/-0.16)E-05 erg/cm^2. The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Xing-Hao Luo (luoxh(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/45116. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43329] GRB 260708A: Fermi-GBM detection
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45115 SUBJECT: GRB 260708A: Fermi-GBM detection DATE: 26/07/08 14:17:47 GMT FROM: Christian Malacaria at INAF-OAR <cmalacaria.astro(a)gmail.com> The Fermi GBM team reports the detection of a likely LONG GRB "At 10:11:16.89 UT on 08 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260708A (trigger 805198281/260708424). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 227.4, Dec = -44.5 (J2000 degrees, equivalent to J2000 15h 09m, -44d 30'), with a statistical uncertainty of 1.6 degrees. The angle from the Fermi LAT boresight is 43 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260708424/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260708424/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260708424/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45115. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43328] GRB 260706A: Further EP-FXT follow-up observation
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45114 SUBJECT: GRB 260706A: Further EP-FXT follow-up observation DATE: 26/07/08 13:58:49 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Pillas (IAP), F. Daigne (IAP), Y.F. Liang (PMO), report on behalf of the SVOM and EP collaborations: EP-FXT performed an additional follow-up observation of GRB 260706A detected by SVOM/ECLAIRs (Alaux et al., GCN 45089) and Fermi/GBM (Fermi GBM Team, GCN 45088). This second follow-up observation epoch started on 2026-07-07 at 19:16:49 (UTC), about 27.1 hr after the SVOM trigger, with a total exposure time of 3 ks. On-ground analysis of the FXT data still detected an uncatalogued source consistent with the previous EP/FXT detection (Liang et al., GCN 45097). The derived average unabsorbed flux is (2.5+/- 0.5) x 10^(-13) erg/s/cm^2 (0.5-10 keV; 1-sigma uncertainty). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45114. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43327] GRB 260706A: SVOM/VT optical upper limits
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45113 SUBJECT: GRB 260706A: SVOM/VT optical upper limits DATE: 26/07/08 09:45:48 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li, L. P. Xin, C. Wu, Y. L. Qiu, Y. N. Ma, J. R. Xu, Z. H. Yao, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), F. Daigne (IAP) and M. Pillas (IAP) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observation to GRB 260706A detected by SVOM/Eclairs (sb26070606, Alaux et al., GCN 45089; Guillot et al., GCN 45103). This burst was also detected by SVOM/GRM (Alaux et al., GCN 45089; Wang et al., GCN 45101) and Fermi/GBM (the Fermi GBM team, GCN 45088; Trigg et al., GCN 45093). The observation started at 2026-07-07T07:42:10 UTC, about 15.506 hours after trigger in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. No credible sources are detected in stacked images within error box of SVOM/Eclairs (Alaux et al., GCN 45089) and EP-FXT (Liang et al., GCN 45097) down to 10-sigma upper limits of 22.0 mag in both channels at the midtime of 17.43 hr post trigger. The magnitudes are in the AB system and are not corrected for Galactic extinction. Our non-detection is consistent with observations from LCO (Saccardi et al., GCN 45098) and REM (Brivio et al., GCN 45100). The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/45113. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43326] EP260707a (by EP-FXT): NOT optical upper limit
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45112 SUBJECT: EP260707a (by EP-FXT): NOT optical upper limit DATE: 26/07/08 04:41:03 GMT FROM: sqjiang at NAOC <sqjiang(a)bao.ac.cn> X. Liu, S.Q. Jiang, Z.P. Zhu, J. An, L.B. He, D. Xu (NAOC), S.Y. Fu (HUST), J.P.U. Fynbo (DAWN/NBI), F. Mustafaj (NOT) report: We observed the field of the uncatalogued X-ray source detected by EP-FXT (Zhou et al., GCNs 45107 & 45111), located within the EP-WXT error circle of the very likely fake event of EP260707a, using the 2.56m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. Observation started at 2026-07-08 01:09:50.53 UT, i.e., 8.41 hr post-burst, and a series of r-band frames were obtained. No new optical transient is detected in the stacked image within the EP-FXT error circle (GCN 45107), down to a 5-sigma limiting magnitude of r ~ 23.0 (AB), calibrated with Pan-STARRS DR2 stars in the field and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45112. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43325] EP260707a is not a real source
by GCN Circulars 08 Jul '26

08 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45111 SUBJECT: EP260707a is not a real source DATE: 26/07/08 02:34:57 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H. Zhou, Y. F. Liang (PMO), K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the follow-up analysis of the X-ray transient candidate EP260707a, initially triggered the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Zhou et al. GCN 45107) also followed by optical telescopes (Liu et al. GCN 45109, Strausbaugh et al. GCN 45110) Following the analysis of the telemetry data, we found that the EP260707a is not a real transient. The uncatalogued X-ray source subsequently detected by the Follow-up X-ray Telescope (FXT) within the WXT error circle is considered as a coincidental alignment, rather than a counterpart to a real transient. We apologize for any inconvenience caused to the community. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45111. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43324] EP260707a: LCOGT Optical Upper Limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45110 SUBJECT: EP260707a: LCOGT Optical Upper Limit DATE: 26/07/07 21:12:22 GMT FROM: Robert Strausbaugh at Eastern Illinois University <rstrausbaugh(a)eiu.edu> R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration: We observed the EP260707a field (Zhou et al., GCN 45107) with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on July 7, from 20:02 to 20:35 UT (corresponding to 3.28 to 3.83 hours after the trigger time) with the SDSS r and i filters. We performed a series of 3x300s exposures in i-band and r-band. We do not detect an uncatalogued source in the FXT error region, consistent with other optical upper limits (Liu et al., GCN 45109). The following magnitudes are calculated using the PanSTARRS catalog as reference: r > 22.1 i > 21.6 These magnitudes are not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45110. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43323] EP260707a: TRT optical upper limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45109 SUBJECT: EP260707a: TRT optical upper limit DATE: 26/07/07 19:33:31 GMT FROM: liuxing(a)nao.cas.cn X. Liu (NAOC), K. Noysena, K. Chanchaiworawit, S. Tinyanont (NARIT), S.Y. Fu (HUST), S.Q. Jiang, J. An, L.B. He, Z.P. Zhu, D. Xu (NAOC) report: We observed the field of EP260707a detected by EP (Zhou et al., GCN 45107) using the 0.7-m telescope of the Thai Robotic Telescope network (TRT), located at New South Wales, Australia (SBO). 4x300s frames in the R-band were obtained at a median time of 1.52 hr post-trigger. No uncatalogued optical transient is detected in the stacked image within the EP/FXT error circle (Zhou et al., GCN 45107), down to a 5-sigma limiting magnitude of R ~ 21.0 (Vega), calibrated with Pan-STARRS DR2 stars in the field converted using Lupton (2005) equations and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45109. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43322] Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45108 SUBJECT: Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB DATE: 26/07/07 19:31:42 GMT FROM: Suman Bala at USRA <sumanbala2210(a)gmail.com> S. Bala (USRA) reports report on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 805087514/260707142 at 03:25:09.33 UT on 07 July 2026, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to Terrestrial Gamma-ray Flash (TGF)." View this GCN Circular online at https://gcn.nasa.gov/circulars/45108. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43321] EP260707a: Einstein Probe detection of an X-ray transient
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45107 SUBJECT: EP260707a: Einstein Probe detection of an X-ray transient DATE: 26/07/07 18:30:09 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H. Zhou, Y. F. Liang (PMO), K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of an X-ray transient by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated EP260707a. The transient triggered EP-WXT (ID: 01709274241) at 2026-07-07T16:45:24 (UTC). The WXT position of the source is R.A. = 306.233 deg, DEC = -26.589 deg (J2000) with an uncertainty of 3 arcmin in radius (90% C.L. statistical and systematic). A follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. Within the WXT error circle, an uncatalogued X-ray source was detected at R.A. = 306.1900 deg, DEC = -26.5853 deg (J2000) with an uncertainty of 20 arcsec in radius (90% C.L. statistical and systematic). Further information will be updated when the telemetry data is received. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45107. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43320] Nova AT2026oyp (ASASSN-26dt): Pre-outburst Swift UVOT observation
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45106 SUBJECT: Nova AT2026oyp (ASASSN-26dt): Pre-outburst Swift UVOT observation DATE: 26/07/07 17:06:06 GMT FROM: Paul Kuin at MSSL <npkuin(a)gmail.com> The LMC nova AT2026oyp (ASASSN-26dt) was observed by Swift UVOT in the UVW1 filter on 2017-11-14 in a 54. s exposure. That predated the eruption reported in ATEL #17878 (Chomiuk et al.) and the nova was reported to have peaked at g=10.5 mag on 2026 June 11. The quescent magnitude in the UVOT UVW1 filter was UVW1 = 19.56 +/- 0.26 (stat) +/- 0.03 (sys) (AB) mag consistent with the other reported quiescent values, at a position RA = 00h 50m 45.11s, Dec = -71d 38m 38.51s (J2000) with uncertainty = +/- 1.05" (90% confidence) marginally consistent with the reported position at RA=01:50:45.142, Dec= -71:38:36.96. View this GCN Circular online at https://gcn.nasa.gov/circulars/45106. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43319] GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45105 SUBJECT: GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B DATE: 26/07/07 15:52:15 GMT FROM: James Freeburn at University of North Carolina at Chapel Hill <jamesfreeburn54(a)gmail.com> James Freeburn (UNC), Tomás Ahumada (NOIRLab), Jillian Rastinejad (UMD), Gokul Srinivasaragavan (UMD/Northwestern), Huei Sears (Rutgers), Anirudh Salgundi (UNC), report on behalf of a larger collaboration: We observed the field of GRB 260705A (SVOM burst-id sb26070502) detected by SVOM (Saccardi et al., GCN 45079) and Fermi (Hamburg et al., GCN 45080) using the SOAR and Gemini-South telescopes. We obtained 8 x 300 s of i-band imaging with SOAR using the Goodman High Throughput Spectrograph (SOAR2026A-018; PI: Andreoni) in imaging mode with the Red camera at a mid-time of 2026-07-07 10:19 UT, corresponding to ~45 hrs after the trigger. We performed SOAR data reduction with a custom pipeline using pre-reduced images from the Goodman pipeline (Torres et al. 2018). We obtained 4 x 120 s of r-band imaging at three different pointings using GMOS on Gemini-South (PI: Srinivasaragavan) at a mid-time of 2026-07-07 09:35 UT and performed image reduction with DRAGONS (Labrie et al. 2019). For both images, we performed image subtraction using SFFT (Hu et al. 2022) against DECam Legacy Survey images. The GMOS image covers ~77% of the SVOM localization (Saccardi et al., GCN 45079), while the resampled Goodman image covers ~65% of the localization. We detect a candidate optical counterpart at: R.A. (J2000) = 03:53:12.49 (58.30204 d) +/- 0.5’’ Dec. (J2000) = -31:39:08.61 (-31.65239 d) +/- 0.5’’ with AB magnitudes, calibrated with SkyMapper DR4 (Onken et al., 2024), of: r = 21.48 +/- 0.08 i = 21.44 +/- 0.04 These magnitudes have not been corrected for Galactic extinction of A_V = 0.028 mag. The brightness of this source is consistent with the upper limits found by LCO (Shi et al., GCN 45084), though these observations were taken ~30 hours prior. This candidate optical counterpart is embedded in a catalogued source, WISEA J035312.50-313908. WISEA J035312.50-313908.7 has no reported proper motion in Gaia DR3 (Gaia Collaboration 2022) and is classified as a ‘high-confidence galaxy’ in DES DR2 (Abbott et al. 2021), therefore we conclude the source is a galaxy. WISEA J035312.50-313908.7 has a photometric redshift of z = 0.178 +/- 0.009 from Legacy Survey DR10 (Duncan et al. 2022). The candidate optical counterpart is consistent with a nuclear origin with an offset of ~0.4” from the host center. We disfavor this counterpart as an AGN given the WISE color of W1-W2 = -0.05 (Cutri et al. 2013) and the absence of an AGN match in the Milliquas catalog (Flesch et al. 2023). We note that GRB 260705B, detected by Fermi (GCN 45081), has a localization consistent with GRB 260705A and was detected ~ 11 hr (~ 40,000 s) after. If these bursts are connected to the same source, this suggests a possible identification as an ultra-long GRB. The extended gamma-ray duration and nuclear location are also reminiscent of jetted TDEs (e.g., Swift J1644+57, Bloom et al. 2011; Swift J2058+05, Cenko et al. 2012; Swift J1112-82, Brown et al. 2015). Further observations are planned to assess the variability of this source. We thank the staff at Gemini-South and SOAR for their assistance with the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/45105. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43318] GRB 260705C: Glowbug gamma-ray detection of a short burst
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45104 SUBJECT: GRB 260705C: Glowbug gamma-ray detection of a short burst DATE: 26/07/07 15:25:19 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 260705C, which was also detected by Fermi/GBM (GCN 45082). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-07-05 13:58:57.840 with a duration of 0.26 s and a total significance of about 19.5 sigma. The light curve comprises a single peak. The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/45104. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43317] GRB 260706A: SVOM/ECLAIRs refined analysis
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45103 SUBJECT: GRB 260706A: SVOM/ECLAIRs refined analysis DATE: 26/07/07 15:08:36 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Authors: S. Guillot, M. Brunet, J. Alaux (IRAP), F. Daigne, M. Pillas (IAP), report on behalf of the SVOM/ECLAIRs team: Using the event-by-event data downloaded through the X-band ground station, we report further analysis of SVOM/ECLAIRs observations of GRB 260706A (SVOM Burst id sb26070606, GCN #45089) with trigger time T0 = 2026-07-06T16:12:23 UTC, which was also detected by Fermi/GBM (GCN #45088). The burst that triggered ECLAIRs onboard shows a multiple peak lightcurve, and the burst duration is T90 = 23.41 +0.64/-0.89 s in the 4-120 keV energy band. The time-averaged spectrum from T0 to T0+24 s in the 5-120 keV energy range is best fitted by a cut-off powerlaw model with alpha = -1.4 +/- 0.1 and Epeak = 38.1 +/- 6.4 keV. With this model, the 4-120 keV fluence is (3.5 +/- 0.3)e-6 erg/cm^2 and the 4-120 keV photon flux is 5.9 +/- 0.3 ph/cm^2/s. All the quoted errors are at the 68% confidence level. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. The SVOM/ECLAIRs point of contact for this burst is: Sebastien Guillot (IRAP) (sebastien.guillot at utoulouse.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/45103. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43316] GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45102 SUBJECT: GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate DATE: 26/07/07 13:16:54 GMT FROM: F. Magnani at Aix-Marseille Université, CPPM/CNRS <francesco.magnani.work(a)gmail.com> GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate Noémie Globus (UNAM), Francesco Magnani (CPPM), Camila Angulo (UNAM), Jean-Grégoire Ducoin (CPPM), Nathaniel R. Butler (ASU), Stéphane Basa (UAR Pytheas), Jean-Luc Atteia (IRAP), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Damien Dornic (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Alan M. Watson (UNAM), W.J Xie (NAOC), Y. H. Cheng (YNU), C. Plasse (HKU), report: We imaged the field of the SVOM GRB 260704A (W.J Xie et al., GCN Circ. 45072) using the DDRAGO two-channel wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-07-05 07:25:02 to 11:20:12 UTC (from 27.7 to 31.7 hours after the trigger) and obtained 104 minutes of simultaneous exposure in the r and z filters. The data were reduced, coadded, and analyzed with the ASU pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. We tentatively detected a faint, uncatalogued source consistent with both the SVOM/MXT error circle (W.J. Xie et al., GCN Circ. 45072) and the EP/FXT error circle (Y.-H. I. Yin et al., GCN Circ. 45078) at: RA (J2000) = 21:14:51.52 = 318.71468 deg, Dec (J2000) = -25:30:29.4 = -25.50816 deg, with an estimated astrometric uncertainty of 0.5 arcsec. The preliminary unsubtracted magnitude derived for that source was: r = 23.54 ± 0.22 z = 22.70 ± 0.27 We reobserved from 2026-07-06 07:18:26 to 09:47:39 UTC (from 51.62 to 54.11 hours after the trigger) and obtained 111 minutes of simultaneous exposure in the r and z filters. Compared to our previous observations, the source has faded. The preliminary unsubtracted magnitude is: r = 24.08 ± 0.23 mag, z = 23.19 ± 0.28 mag. The detection of the source in two independent optical bands, together with its fading between the two observing epochs, makes it a possible candidate for the optical counterpart of the GRB. We thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/45102. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43315] GRB 260706A: SVOM/GRM observation
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45101 SUBJECT: GRB 260706A: SVOM/GRM observation DATE: 26/07/07 12:40:33 GMT FROM: Yue Wang <m18509381757(a)163.com> SVOM/GRM team: Yue Wang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Sebastien Guillot (IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 260706A at 2026-07-06T16:12:22.000 (T0), which is also detected by SVOM/ECLAIRs (J. Alaux et. al., GCN #45089) and Fermi/GBM (Fermi GBM team, GCN #45088, #45093). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple peaks with a T90 of 31 +12/-8 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260706A.png In addition, the position of this burst, as determined by SVOM/ECLAIRs (RA = 33.8323 deg, Dec = -49.1375 deg, Error = 3.17 arcmin, GCN #45089), is used for the spectral analysis. With this localization, the time-averaged spectrum from T0-3.0 to T0+30.0 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.47 +0.16/-0.15 and the cutoff energy, parameterized as Epeak, is 53.98 +5.09/-4.96 keV. The event fluence (10-1000 keV) in this time interval is (3.96 +0.21/-0.19)E-06 erg/cm^2. The localization of GRB 260706A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260706A_amati.png The localization of GRB 260706A in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260706A_yonetoku.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM/GRM point of contact for this burst is: Yue Wang (IHEP) (yuewang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/45101. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43314] GRB 260706A: REM optical/NIR observations
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45100 SUBJECT: GRB 260706A: REM optical/NIR observations DATE: 26/07/07 12:14:45 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro, P. D'Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 260706A, detected by SVOM/ECLAIRs (Alaux et al., GCN 45089) and Fermi/GBM (Trigg et al., GCN 45093) with the REM 60 cm robotic telescope located at the ESO observatory of La Silla (Chile). The observations were carried out in the g,r,i,z, and K bands, started on 2026-07-07 at 04:49:10 UT (i.e. 12.6 hr after the burst) and lasted for about 1 hr. From preliminary photometry, we do not detect any uncatalogued source within the EP/FXT error box (Liang et al., GCN 45097) down to the following 3sigma limits: r > 19.4 (AB; calibrated against the SkyMapper catalogue), at a mid-time of 13.5 hr after the trigger; K > 13.6 (Vega; calibrated against the 2MASS catalogue), at a mid-time of 13.3 hr after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/45100. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43313] IceCube-260704A: No candidates from the Zwicky Transient Facility
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45099 SUBJECT: IceCube-260704A: No candidates from the Zwicky Transient Facility DATE: 26/07/07 10:32:00 GMT FROM: Robert David Stein at JSI <rdstein(a)umd.edu> Akshay Eranhalodi (DESY), Robert Stein (JSI), Cristobal Zilleruelo Cañas (DESY), Jannis Necker (Leiden University), and Anna Franckowiak (Ruhr University Bochum) report, On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-260704A (Zegarelli et. al, GCN 45075) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2026-07-04 07:25 UTC, approximately 0.1 hours after event time. We covered 98.4% (0.8 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019). We are left with the following high-significance transient candidate by our pipeline, lying within the 90.0% localization of the skymap: +--------------------------------------------------------------------------------+ | ZTF Name | IAU Name | RA (deg) | DEC (deg) | Filter | Mag | MagErr | +--------------------------------------------------------------------------------+ | ZTF19ablafcb | ------- | 320.5248614 | +34.5149697 | g | 21.09 | 0.20 | +--------------------------------------------------------------------------------+ ZTF19ablafcb was first detected by ZTF on 2019-07-31. It is located at a galactic latitude of -10.94 degrees. Based on its WISE colours (W1-W2=0.6), historical optical variability in ZTF data, and nuclear location, it is likely that the source is an AGN. The source is clearly visible in archival PS1 imaging, and the source does not appear to be significantly flaring relative to this baseline. We therefore find no temporal evidence to suggest that the AGN is associated to the high-energy neutrino. We do not select the AGN WISEA J212302.62+340634.2, which was observed by Adami et al. (GCN 45085). This is expected, given that the source was reported to not be flaring. Our ZTF ToO program only targets AGN which are undergoing flares coincident with the detection of neutrinos. ZTF and GROWTH are worldwide collaborations comprising Caltech/IPAC, USA; University of Maryland, USA; University of California, Berkeley, USA; Cornell University, USA; Drexel University, USA; University of North Carolina at Chapel Hill, USA; Institute of Science and Technology, Austria; National Central University, Taiwan; OKC, Sweden; DZA, Germany. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf) View this GCN Circular online at https://gcn.nasa.gov/circulars/45099. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43312] GRB 260706A: LCO optical upper limit
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45098 SUBJECT: GRB 260706A: LCO optical upper limit DATE: 26/07/07 09:30:30 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> A. Saccardi (CEA/Irfu), D. Turpin (CEA/Irfu), F. Daigne, M. Pillas (IAP), report on behalf of the SVOM mission team: We observed the field of GRB 260706A detected by SVOM/ECLAIRs (Alaux et al., GCN 45089) and Fermi/GBM (Fermi GBM team, GCN 45088; Trigg et al., GCN 45093), with the LCO 1m telescope at Cerro Tololo Observatory equipped with the Sinistro instrument. Our observation started on 2026-07-07 at 08:15:35 UT (about 16 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r filter. In the stacked image, we do not detect any new source within the EP/FXT error box (Liang et al., GCN 45097). We measure the following upper limit calibrated against the SkyMapper DR4 catalog, and not corrected for Galactic extinction: r > 22.3 AB (3-sigma, mid-time 16.14 hr after the trigger). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/45098. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43311] GRB 260706A: EP-FXT follow-up observation
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45097 SUBJECT: GRB 260706A: EP-FXT follow-up observation DATE: 26/07/07 07:46:49 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.F. Liang, H. Zhou (PMO), K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAOC) on behalf of the Einstein Probe (EP) team: EP-FXT performed an automatically follow-up observation of GRB 260706A detected by SVOM/ECLAIRs (Alaux et al., GCN 45089), which also triggered Fermi-GBM (Fermi GBM team, GCN 45088; Trigg et al., GCN 45093). The follow-up observation started at 2026-07-06 17:44:38 (UTC), about 1.5 hr after the SVOM trigger, with a total exposure time of around 5462 ks. On-ground analysis of the FXT data found an uncatalogued source within the ECLAIRs error circle at R.A., Dec. =33.8136, -49.1514 deg (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic). The derived average unabsorbed flux is 6.21 (-0.87/+1.03) x 10^(-12) erg/s/cm^2 (0.5-10 keV; 1-sigma uncertainty). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45097. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43310] GRB 260707A: Fermi GBM Final Real-time Localization
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45096 SUBJECT: GRB 260707A: Fermi GBM Final Real-time Localization DATE: 26/07/07 03:36:24 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 03:25:09 UT on 7 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260707A (trigger 805087514.330134 / 260707142). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 283.4, Dec = -54.7 (J2000 degrees, equivalent to J2000 18h 53m, -54d 42'), with a statistical uncertainty of 13.3 degrees. The angle from the Fermi LAT boresight is 165.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260707142/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260707142/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260707142/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45096. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43309] The EP-WXT trigger 01709274151 is likely a flaring star
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45095 SUBJECT: The EP-WXT trigger 01709274151 is likely a flaring star DATE: 26/07/07 02:12:06 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. F. Liang，H. Zhou (PMO)，K. R. Ni (CCNU), C.-K. Kan (HKU), H. Sun (NAO, CAS). on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274151, detected at 2026-07-06T21:58:41, is likely associated with a stellar flare originating from one of two candidate stars within the FXT error circle: StKM 1-1292 or PM J15587+2351E. If the flare occurred on StKM 1-1292, the corresponding X-ray luminosity (0.5–4.0 keV) is estimated to be around 2.3 x 10^(31) erg/s. Alternatively, if it originated from PM J15587+2351E, the implied flare luminosity would be around 2.4 x 10^(31) erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45095. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43308] The EP-WXT trigger 01709274141 is likely a flaring star
by GCN Circulars 07 Jul '26

07 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45094 SUBJECT: The EP-WXT trigger 01709274141 is likely a flaring star DATE: 26/07/07 02:07:57 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> K.R. Ni (CCNU), Y. F. Liang，H. Zhou (PMO)，C.-K. Kan (HKU), H. Sun (NAO, CAS). on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274141 at the time of 2026-07-06 20:01:19, is likely a stellar flare associated with CD-25 16313. The estimated flux of the flare is around 2.1 x 10^-11 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 8.6 x 10^31 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45094. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43307] GRB 260706A: Fermi GBM Observation
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45093 SUBJECT: GRB 260706A: Fermi GBM Observation DATE: 26/07/06 20:28:09 GMT FROM: atrigg2(a)lsu.edu A. C. Trigg (NPP ORAU, NASA MSFC) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 16:12:21.43 UT on 06 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260706A (trigger 805047146/260706675), which was also detected by SVOM/ECLAIRs (J. Alaux et al. 20026, GCN 45089). The Fermi GBM on-ground location is consistent with the SVOM/ELCAIRs position. The angle from the Fermi LAT boresight is 43 degrees. The GBM light curve displays two peaks with a duration (T90) of about 17 s (50-300 keV). The time-averaged spectrum from T0+0.001 to T0+30.616 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.13 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 47.1 +/- 0.6 keV. The event fluence (10-1000 keV) in this time interval is (3.18 +/- 0.08)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+15 s in the 10-1000 keV band is 5.3 +/- 0.3 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 39.1 +/- 0.5 keV, alpha = -0.71 +/- 0.01 and beta = -2.63 +/- 0.03. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/45093. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43306] IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45092 SUBJECT: IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube DATE: 26/07/06 20:24:10 GMT FROM: Sam Hori at IceCube/U Wisc-Madison <sahori(a)wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-260704A (https://gcn.nasa.gov/circulars/45075) in a time range of 1000 seconds centered on the alert event time (2026-07-04 07:08:38.191 UTC to 2026-07-04 07:25:18.191 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-260704A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.4e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260704A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 6e+04 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2026-07-03 07:16:58.191 UTC to 2026-07-05 07:16:58.191 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.6e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260704A in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/45092. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43305] IPN triangulation of GRB 260627A
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45091 SUBJECT: IPN triangulation of GRB 260627A DATE: 26/07/06 19:33:12 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams, J. Benkhoff on behalf of the BepiColombo team, A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 260627A was detected by Konus-Wind, Mars-Odyssey (HEND), and BepiColombo (MGNS), at about 6500 s UT (01:48:20). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 97.683 (06h 30m 44s) -11.018 (-11d 01' 04") Corners: 96.021 (06h 24m 05s) -10.787 (-10d 47' 15") 98.614 (06h 34m 27s) -12.214 (-12d 12' 51") 99.375 (06h 37m 30s) -11.186 (-11d 11' 10") 96.787 (06h 27m 09s) -9.778 ( -9d 46' 42") --------------------------------------------- The error box area is 3.6 sq. deg, and its maximum dimension is 3.3 deg (the minimum one is 1.2 deg). The Sun distance was 34 deg. This localization may be improved. A triangulation map and HEALPix FITS file are posted at https://www.ioffe.ru/LEA/GRBs/GRB260627_T06499/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/45091. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43304] GRB 260705A: SVOM/ECLAIRs refined analysis
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45090 SUBJECT: GRB 260705A: SVOM/ECLAIRs refined analysis DATE: 26/07/06 17:19:11 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> N. Dagoneau, A. Saccardi (CEA), report on behalf of the SVOM/ECLAIRs team: Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 260705A (SVOM burst-id sb26070502). The burst that triggered ECLAIRs onboard (GCN 45079) consists of a single broad peak lightcurve with a duration of T90 = 35.55 -9.04 / +6.05 (4-80 keV). The time-averaged spectrum (from T0-5.49 s to T0+29.72 s) in the energy range 5-120 keV is best fit by a powerlaw with an index of -1.68 ± 0.09. With this model, the 4-120 keV fluence is (1.053 ± 0.087)*E-6 erg/cm² and the 4-120 keV photon flux is 1.002 ± 0.059 ph/cm²/s. All the quoted errors are at the 68% confidence level. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The SVOM/ECLAIRs point of contact for this burst is: N. Dagoneau (nicolas.dagoneau at cea.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/45090. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43303] GRB 260706A: SVOM detection of a burst
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45089 SUBJECT: GRB 260706A: SVOM detection of a burst DATE: 26/07/06 16:50:02 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> J. Alaux, M. Brunet, S. Guillot, M. Boiziot (IRAP), F. Daigne, M. Pillas (IAP) report on behalf of the SVOM mission team: At 2026-07-06T16:12:23 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260706A (SVOM burst-id sb26070606), which is also detected by Fermi/GBM (GCN 45088). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 19 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 31.31 in the [8-120] keV energy band over a time window of 20.48 seconds starting at 2026-07-06T16:12:20. The localization of the best alert is R.A., Dec. 33.8323, -49.1375 degrees: R.A. (J2000) = 2h15m19.75s Dec. (J2000) = -49d08m15.14s with a 90% confidence level (C.L.) radius of 3.17 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a multiple peak structure. This burst also triggered SVOM/GRM at 2026-07-06T16:12:21 on a timescale of 1 second with an SNR of 9.50. The SVOM/GRM light curve showed a multiple peak structure with a T90 duration of about 22.9 -3.8/+10.5 seconds. SVOM slewed to the burst. No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Frédéric Daigne: daigne(a)iap.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45089. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43302] GRB 260706A: Fermi GBM Final Real-time Localization
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45088 SUBJECT: GRB 260706A: Fermi GBM Final Real-time Localization DATE: 26/07/06 16:24:06 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 16:12:21 UT on 6 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260706A (trigger 805047146.426808 / 260706675). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 17.5, Dec = -40.6 (J2000 degrees, equivalent to J2000 01h 10m, -40d 36'), with a statistical uncertainty of 5.4 degrees. The angle from the Fermi LAT boresight is 57.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260706675/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260706675/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260706675/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45088. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43301] The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45087 SUBJECT: The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare DATE: 26/07/06 14:39:25 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng (UCB), Xuhui Han (NAOC), Pinpin Zhang (NAOC) and Alexei V. Filippenko (UCB) report on behalf of the KAIT GRB team: The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at Lick Observatory, automatically responded to the EP-WXT trigger 01709274014 (Jiang et al. GCN 45086) starting at 09:52 UT, about 8 minutes after the trigger. A set of B, V, R, I and clear (roughly R) filter images were obtained and lasted for ~1.2 hours. We performed the photometry on the suggested flare star HD 183870B and see its brightness decreased in all bands, especially in B band decayed from ~13.6 mag to ~14.8 mag in about 1.2 hours, thus confirming the EP X-ray trigger is related to the stellar flare. View this GCN Circular online at https://gcn.nasa.gov/circulars/45087. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43300] The EP-WXT trigger 01709274014 is likely a flaring star
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45086 SUBJECT: The EP-WXT trigger 01709274014 is likely a flaring star DATE: 26/07/06 10:52:31 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> S. Q. Jiang (NAO, CAS), D. F. Hu (PMO, CAS), C.-K. Kan (HKU), X. Tian(GXU), H. W. Pan (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709274014 at the time of 2026-07-06T09:44:54, is likely a stellar flare associated with the high proper motion star HD 183870B. The estimated flux of the flare is around 1.8 x 10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 6.73 x 10^(30) erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45086. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43299] IceCube260704A: OHP/T193 optical observations
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45085 SUBJECT: IceCube260704A: OHP/T193 optical observations DATE: 26/07/06 10:52:28 GMT FROM: Christophe Adami at LAM <christophe.adami(a)lam.fr> C. Adami (LAM/Pytheas/AMU), S. Basa (LAM/OHP/Pytheas/AMU), E. Le Floc'h (CEA/Irfu), F. Schussler (CEA Paris-Saclay) report on behalf of a larger collaboration: We observed the WISEA J212302.62+340634.2 source (no available public spectroscopy in NED), at ~4.9arcmin from the mean coordinates of the IceCube event IceCube260704A (Zegarelli et al., GCN 45075), using the T193cm telescope at Observatoire de Haute-Provence (France) with the MISTRAL spectro-imager. We obtained 6 min of exposure in the r-band starting at 2026-07-05T02:04 UT (18.8h after the Zegarelli et al. trigger). In the preliminar stacked images, we do not detect significant magnitude change as compared to the PanStarrs r-band magnitude of r=18.05. We also observed in spectroscopic mode: - We obtained a total of 60 min of exposures (2 x 30min) with the MISTRAL spectroscopic blue setting from 4000 to 7800 AA, starting at 2026-07-05 00:18 UT (17h after the trigger). With a preliminar data reduction, we very clearly detect Halpha (apparently with a single peak) at a redshift of 0.1402. We also detect very clearly an intense double-peaked [NII]@6584A emission line. No other emission line are visible. We detect however Magnesium@5175A, CaFe@5269A and NaD@5892A in absorption. The log(Halpha/[NII]) is close to -0.1, likely placing this galaxy in the AGN/LINER region in a BPT diagram. The two peaks of the [NII] emission line are separated by ~300km/s. - We then obtained a second serie of 3 x 30min starting at 2026-07-05 23:13 UT (~40h after the trigger). With a preliminar data reduction, we still clearly detect Halpha with a single peak at the same redshift and with a similar intensity. The [NII]@6584A emission line may show a mild evolution: the flux is stronger and the two peaks are much less separated and proeminent. The photometric calibration was performed using nearby stars from the PanSTARRS catalog and the STDWeb/STDPipe tools (Karpov 2025), is in the AB system, and is not corrected for Galactic extinction. We acknowledge the excellent support from Observatoire de Haute-Provence and in particular Jean Pierre Troncin. View this GCN Circular online at https://gcn.nasa.gov/circulars/45085. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43298] GRB 260705A: LCO optical upper limits
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45084 SUBJECT: GRB 260705A: LCO optical upper limits DATE: 26/07/06 08:47:12 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y.Y. Shi (GXU), A. Saccardi (CEA/Irfu), C. Wu (NAOC), L.P. Xin (NAOC), D. Turpin (CEA/Irfu), X. Tian (GXU), Z. Liu (GZNU) report on behalf of the SVOM mission team: We observed the field of GRB 260705A (SVOM burst-id sb26070502) detected by SVOM (Saccardi et al., GCN 45079) with the LCO 1m telescope at South African Astronomical Observatory equipped with the Sinistro instrument. Our observation started on 2026-07-06 at 03:52:16 UT (about 14.76 hr after the trigger) and we obtained 3x200 s exposures in the SDSS r and 3x200 s exposures in the Pan-STARRS z filters. In the stacked image, we do not detect any new source within the SVOM/ECLAIRs error box. We measure the following upper limits calibrated against the DESI Legacy Imaging Surveys DR10 catalog, and not corrected for Galactic extinction: r > 20.9 AB (5-sigma, mid-time 14.85 h after the trigger); z > 19.9 AB (5-sigma, mid-time 15.06 h after the trigger). This project is funded by the SVOM collaboration. View this GCN Circular online at https://gcn.nasa.gov/circulars/45084. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43297] GRB 260704A: NOT optical upper limits
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45083 SUBJECT: GRB 260704A: NOT optical upper limits DATE: 26/07/06 06:20:45 GMT FROM: Daniele Bjørn Malesani at Cosmic Dawn Center, Niels Bohr Institute <daniele.malesani(a)nbi.ku.dk> D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), A. Martin-Carrillo (UCD), A. Saccardi (CEA/Irfu), F. Mustafaj (NOT) report on behalf of a larger collaboration: We observed the field of GRB 260704A reported by SVOM/ECLAIRs (Xie et al., GCN 45072), using the ALFOSC camera mounted on the Nordic Optical Telescope (NOT). We obtained 9x120 s exposures in the SDSS i band at mid time 2026 Jul 5.116 UT (23.1 hr after the trigger). Our observations targeted the location of the X-ray source detected by SVOM/MXT (Xie et al., GCN 45072) and EP/FXT (Yin et al., GCN 45078). Within the EP/FXT error circle, we note the presence of a bright star (i = 15.46). Its magnitude in our image is consistent with the archival value. Its TESS light curve does not show historical variability either. This makes the star not likely related to the X-ray source. Furthermore, in the stack of our images, no new optical source is detected within the EP/FXT error region, down to the 3-sigma limiting AB magnitudes of i > 22.5 (calibrated against nearby stars from the Pan-STARRS catalog and not corrected for Galactic extinction). View this GCN Circular online at https://gcn.nasa.gov/circulars/45083. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43296] GRB 260705C: Fermi GBM Final Localization
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45082 SUBJECT: GRB 260705C: Fermi GBM Final Localization DATE: 26/07/06 00:40:46 GMT FROM: rhamburg(a)usra.edu The Fermi GBM team reports the detection of a likely SHORT GRB "At 13:58:58.99 UT on 05 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260705C (trigger 804952743/260705583). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 251.67, Dec = 55.55 (J2000 degrees, equivalent to J2000 16h 46m, +55d 32'), with a statistical uncertainty of 11.60 degrees. The angle from the Fermi LAT boresight is 21 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705583/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45082. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43295] GRB 260705B: Fermi GBM Final Real-time Localization
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45081 SUBJECT: GRB 260705B: Fermi GBM Final Real-time Localization DATE: 26/07/06 00:19:12 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 22:46:36 UT on 5 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260705B (trigger 804984401.559966 / 260705949). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 68.5, Dec = -30.8 (J2000 degrees, equivalent to J2000 04h 33m, -30d 48'), with a statistical uncertainty of 3.0 degrees. The angle from the Fermi LAT boresight is 77.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260705949/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45081. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43294] GRB 260705A: SVOM detection of a burst
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45079 SUBJECT: GRB 260705A: SVOM detection of a burst DATE: 26/07/05 14:25:13 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> A. Saccardi (CEA/Irfu), N. Dagoneau (CEA/Irfu), D. Turpin (CEA/Irfu), X. Tian (GXU), Z. Liu (GZNU), report on behalf of the SVOM mission team: At 2026-07-05T13:06:46 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260705A (SVOM burst-id sb26070502). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 16 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 11.38 in the [8-120] keV energy band over a time window of 40.96 seconds starting at 2026-07-05T13:06:28. The localization of the best alert is R.A., Dec. 58.2851, -31.6391 degrees: R.A. (J2000) = 3h53m08.43s Dec. (J2000) = -31d38m20.61s with a 90% confidence level (C.L.) radius of 7.06 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a broad peak structure with a T90 duration of about 18.387 (-3.43 +11.095). This burst was also detected by SVOM/GRM with a significance of 10.40. The SVOM/GRM light curve showed a broad peak structure with a T90 duration of about 33.216 (-8.32 +11.914). Due to sun constraint, no immediate slew was performed on this burst. No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Xiao Tian: tianxiao(a)st.gxu.edu.cn Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45079. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43293] Fermi GBM Sub-Threshold Detection of GRB 250705A
by GCN Circulars 06 Jul '26

06 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45080 SUBJECT: Fermi GBM Sub-Threshold Detection of GRB 250705A DATE: 26/07/05 20:33:37 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) and P. Veres (UAH) report on behalf of the Fermi-GBM Team: SVOM ECLAIRs detected GRB 250702A on 2026-07-05 at 13:06:46 UTC (Saccardi et al 2026; GCN 45079). There was no Fermi-GBM onboard trigger around this event time. An automated, blind search for gamma-ray bursts below the onboard triggering threshold in Fermi-GBM identified no candidates. The GBM Targeted Search [1], the most sensitive coherent search for GRB-like signals in GBM, identified a transient about 25 seconds after the SVOM ECLAIRs best SNR time of 2026-07-05 13:06:28 UTC. The Fermi-MET for this transient is 804949617.957 s. The transient is found most significantly on the 32 s timescale with a false alarm rate of 1.4e-04 Hz. The Targeted Search localization is found to be spatially consistent with the SVOM ECLAIRs localization. The GBM Targeted Search event was found with the highest significance using a "normal" spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3) for a GRB. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/45080. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43292] GRB 260704A: EP-FXT follow-up observation
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45078 SUBJECT: GRB 260704A: EP-FXT follow-up observation DATE: 26/07/04 14:56:07 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin, C.-K. Kan (HKU), Y. H. Cheng (YNU), S.Y. Fu (HUST). Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed an automatically follow-up observation of GRB 260704A detected by SVOM/ECLAIRs (Xie et al., GCN 45072). The follow-up observation started at 2026-07-04T04:49:23 (UTC), about 1 hr after the SVOM trigger, with a total exposure time of around 2.6 ks. On-ground analysis of the FXT data found an uncatalogued source within the ECLAIRs and MXT error circles at R.A., Dec. = 318.7151, -25.5074 deg (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic). The derived average unabsorbed flux is 1.49 (-0.22/+0.26) x 10^(-12) erg/s/cm^2 (0.5-10 keV; 1-sigma uncertainty). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45078. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43291] GRB 260629A: SVOM/GRM observation of a short burst
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45077 SUBJECT: GRB 260629A: SVOM/GRM observation of a short burst DATE: 26/07/04 13:25:18 GMT FROM: Yue Wang <m18509381757(a)163.com> SVOM/GRM team: Yue Wang, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Olivier Godet (IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered on-ground by GRB 260629A at 2026-06-29T15:06:59.000 (T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45056), AstroSat CZTI (Harsha et. al., GCN #45074) and GECAM-A (Yue Wang et al., GCN #45076). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a single pulse with a T90 of 1.20 +1.55/-0.65 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260629A.png In addition, the position of this burst, as determined by Fermi/GBM (RA = 146.1, Dec = 70.6, Error = 10.5, GCN #45056), is located at about 138 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-1.0 to T0+2.0 s is best fitted by a power law function. The power law index is -1.89 +0.24/-0.39. The event fluence (10-1000 keV) in this time interval is (2.35 +0.42/-0.40)E-06 erg/cm^2. The localization of GRB 260629A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260629A_amati.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM/GRM point of contact for this burst is: Yue Wang (IHEP) (yuewang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/45077. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43290] GRB 260629A: GECAM-A observation of a short burst
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45076 SUBJECT: GRB 260629A: GECAM-A observation of a short burst DATE: 26/07/04 11:20:10 GMT FROM: Yue Wang <m18509381757(a)163.com> Yue Wang, Chen-Wei Wang, Shao-Lin Xiong (IHEP) report on behalf of GECAM team: GECAM-A was triggered on-ground by GRB 260629A at 2026-06-29T15:06:59.000 UTC (denoted as T0), which is also detected by Fermi/GBM (Fermi GBM team, GCN #45056) and AstroSat CZTI (Harsha et. al., GCN #45074). According to the GECAM-A light curves in about 70-6000 keV, this burst mainly consists of a single pulse with a duration (T90) of 3.20 +1.13/-1.10 s. The GECAM-A light curve can be found here: https://www.bursthub.cn//admin/static/gecamagrb260629A.png Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission originally consists of two micro-satellites (GECAM-A and GECAM-B) launched in Dec. 2020. As the third member of GECAM constellation, GECAM-C was launched onboard SATech-01 experimental satellite in July 2022. GECAM mission is funded by the Chinese Academy of Sciences (CAS). View this GCN Circular online at https://gcn.nasa.gov/circulars/45076. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43289] IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45075 SUBJECT: IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 26/07/04 09:34:08 GMT FROM: A. Zegarelli at Ruhr University Bochum <azegarelli(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 26-07-04 at 07:16:58.19 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. Documentation regarding the alert streams and their astrophysical purity can be found here: https://gcn.nasa.gov/missions/icecube. This alert has an estimated false alarm rate of 0.8177 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/142791_45913213.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 26-07-04 Time: 07:16:58.19 UT RA: 320.67 (+0.57/-0.55 deg 90% PSF containment) J2000 Dec: 34.14 (+0.45/-0.47 deg 90% PSF containment) J2000 As announced in GCN Circular 43419 (https://gcn.nasa.gov/circulars/43419) IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'. The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts. The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX, where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link is provided through the GCN schema distributed via Kafka. Detailed documentation describing the alert distribution, schemas, and probability maps is available at: https://gcn.nasa.gov/missions/icecube. No known gamma-ray sources listed in the Fermi LAT 16-year Source List (FL16Y) are located within the 90% uncertainty region of this event. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu View this GCN Circular online at https://gcn.nasa.gov/circulars/45075. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43288] GRB 260629A: AstroSat CZTI detection
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45074 SUBJECT: GRB 260629A: AstroSat CZTI detection DATE: 26/07/04 08:18:04 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> Harsha K. H. (IUCAA), S. Salunke (IUCAA), A. Arya (IITB), A. Goyal (IITB), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a Short GRB 260629A which was also detected by Fermi (GBM Team, GCN Circ. 45056). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-06-29 15:06:59 UTC. The measured peak count rate associated with the burst is 108 (+70, -15) counts/s above the background in the combined data of three quadrants (out of four), with a total of 96 (+49, -50) counts. The local mean background count rate was 205 (+4, -6) counts/s. We measure a T90 of 0.89 (+0.45, -0.48) s from the cumulative CZT light curve. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-06-29 15:06:59 UTC. The measured peak count rate associated with the burst is 378 (+65, -73) counts/s above the background in the combined data of all quadrants, with a total of 382 (+169, -188) counts. The local mean background count rate was 1283 (+7, -8) counts/s. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 for our detection. CZTI data products like interactive and downloadable light curves for this GRB can be found at: http://astrosat.iucaa.in/cift/cift_products/520441618.77/S520441618.77_deta… CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb View this GCN Circular online at https://gcn.nasa.gov/circulars/45074. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43287] EP260703a: EP-FXT follow-up observation
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45073 SUBJECT: EP260703a: EP-FXT follow-up observation DATE: 26/07/04 04:58:22 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), G. L. Huang (IHEP, CAS), Z.-Y. Jian (HKU), X. Mao and Y. Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of EP260703a (R.-Z. Li et al., GCN 45070) starting at 2026-07-03T14:23:53 (UTC), approximately 11.17 hours after the WXT detection. With an exposure time of 6.1 ks, no significant X-ray source was detected within the 2.7 arcmin radius of the EP-WXT position. The derived 0.5-10 keV upper limit is about 7.6e-14 erg cm^-2 s^-1 (90% C.L.). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45073. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43286] GRB 260704A: SVOM detection of a possible GRB
by GCN Circulars 04 Jul '26

04 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45072 SUBJECT: GRB 260704A: SVOM detection of a possible GRB DATE: 26/07/04 04:49:49 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> W.J XIE (NAOC), C. PLASSE (HKU), Y.H CHENG (YNU), X.TIAN (GXU) report on behalf of the SVOM mission team: At 2026-07-04T03:41:05 UTC (T0), SVOM/ECLAIRs triggered and located an a possible GRB (SVOM burst-id sb26070403).The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was only detected by the Image Trigger (IMT), which produced a sequence of 3 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 7.66 in the [5-20] keV energy band over a time window of 40.96 seconds starting at 2026-07-04T03:40:24. The localization of the best alert is R.A., Dec. 318.5239, -25.6141 degrees (J2000) with a 90% confidence level (C.L.) radius of 10.25 arcmin (including systematic error of 2 arcmin added in quadrature). There is a high proper motion star LP 873-16 in the ECLAIRs error box. SVOM slewed to the burst. SVOM/MXT began observing the field at 2026-07-04T03:43:24 UTC, 139 seconds after T0. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec. 318.7072, -25.5102 degrees: R.A. (J2000) = 21h14m49.74s Dec. (J2000) = -25d30m36.89s with a 90% C.L. radius of 33.97 arcseconds. This location is 11.72 arcminutes from the ECLAIRs onboard position. This position may be improved as more data is received. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is : yhcheng(a)mail.ynu.edu.cn Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/45072. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43285] GRB 260703B: Fermi GBM Final Localization
by GCN Circulars 03 Jul '26

03 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45071 SUBJECT: GRB 260703B: Fermi GBM Final Localization DATE: 26/07/03 19:21:18 GMT FROM: Angus Jameson <abj0023(a)uah.edu> The Fermi GBM team reports the detection of a likely LONG GRB "At 02:25:05.66 UT on 03 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260703B (trigger 804738310/260703101). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 310.5, Dec = 47.9 (J2000 degrees, equivalent to J2000 20h 42m, +47d 54'), with a statistical uncertainty of 5.1 degrees. The angle from the Fermi LAT boresight is 19 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260703101/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260703101/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260703101/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45071. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43284] EP260703a: EP-WXT detection of a fast X-ray transient
by GCN Circulars 03 Jul '26

03 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45070 SUBJECT: EP260703a: EP-WXT detection of a fast X-ray transient DATE: 26/07/03 12:44:47 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R.-Z. Li (YNAO, CAS), G. L. Huang (IHEP, CAS), Z.-Y. Jian (HKU), X. Mao and Y. Liu (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient, designated EP260703a (notice ID: 11900792707), by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission . The transient was identified in the telemetry data. The transient started at 2026-07-03T03:13:57 (UTC) and lasted for about 50s, with a peak flux of ~ 2 x 10^(-9) erg cm^-2 s^-1 in 0.5-4 keV. The position of the transient is R.A. = 274.7265 deg, Dec. = -62.6004 (J2000), with an uncertainty radius of 2.7 arcmin in radius (90% confidence level, including both statistical and systematic uncertainties). There are no known X-ray sources in the WXT error circle. The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 5.56×10^20 cm^-2 and a photon index of 0.22 (-1.17/+1.08). The derived average unabsorbed 0.5-4 keV flux is 1.46 (-0.81/+2.22) x 10^(-9) erg cm^-2 s^-1. The uncertainties are at the 90% confidence level for the above parameters. Follow-up observations by EP-FXT will be arranged. Launched on 2024 January 9, Einstein Probe is a space-based X-ray observatory designed to monitor the dynamic X-ray sky and perform rapid follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45070. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43283] EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
by GCN Circulars 03 Jul '26

03 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45069 SUBJECT: EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation DATE: 26/07/03 07:34:40 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> C. Y. Dai (NJU), X. Mao, H. N. Yang, C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of an X-ray transient, designated EP260628b, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient was identified in the telemetry data. The transient started at 2026-06-28T10:04:53 (UTC) and lasted for about 1000 s. The position of the transient is R.A. = 327.606 deg, Dec. = -29.324 deg (J2000), with an uncertainty radius of 2.6 arcmin (90% confidence level, including both statistical and systematic uncertainties). The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 2.0 x 10^20 cm^-2 and a photon index of 1.40 +/- 0.46. The derived average unabsorbed 0.5-4 keV flux is 7.18 (-1.80/+2.41) x 10^-11 erg cm^-2 s^-1. The uncertainties are at the 90% confidence level for the above parameters. EP-FXT performed a follow-up observation of EP260628b starting at 2026-06-29T09:55:12 (UTC), approximately 1 day after the WXT detection. With an exposure time of 1.7 ks, two X-ray sources were detected within the 2.6 arcmin radius of the EP-WXT position. The first source (EPF_J215025.7-291939) is located at R.A. = 327.6070 deg, Dec. = -29.3276 deg (J2000), with an uncertainty radius of about 10 arcsec (90% C.L., including statistical and systematic uncertainties). The angular separation from the WXT position is 0.28 arcmin. Its 0.5-10 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 2.0 x 10^20 cm^-2 and a photon index of 3.09 (-0.59/+0.59). The derived unabsorbed 0.5-10 keV flux is 1.61 (-0.30/+0.45) x 10^-13 erg cm^-2 s^-1. The second source (EPF_J215025.3-291849) is located at R.A. = 327.6054 deg, Dec. = -29.3136 deg (J2000), with an uncertainty radius of about 10 arcsec. The angular separation from the WXT position is 0.56 arcmin. Its 0.5-10 keV spectrum can also be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 2.0 x 10^20 cm^-2 and a photon index of 2.61 (-0.55/+0.60). The derived unabsorbed 0.5-10 keV flux is 1.71 (-0.38/+0.62) x 10^-13 erg cm^-2 s^-1. No known X-ray sources are found within either FXT error circle. Further follow-up observations by EP-FXT will be arranged. Given that the two FXT sources are located close to each other and show comparable X-ray fluxes and similar spectral properties, the association with the WXT transient and the nature of the event remain unclear. Further multi-wavelength follow-up observations are encouraged. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45069. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43282] Fermi trigger No 804738310: Global MASTER-Net observations report
by GCN Circulars 03 Jul '26

03 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45068 SUBJECT: Fermi trigger No 804738310: Global MASTER-Net observations report DATE: 26/07/03 04:33:55 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAGH robotic telescope [1] located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB260703.10 (trigger No 804738310,21h 00m 43.92s , +48d 28m 01.2s, R=19.2) errorbox 4283 sec after notice time and 4323 sec after trigger time at 2026-07-03 03:37:09 UT, with upper limit up to 17.8 mag. Observations started at twilight. The observations began at zenith distance = 69 deg. The sun altitude is -13.3 deg. The galactic latitude b = 1 deg., longitude l = 89 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3412721 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 4354 | 2026-07-03 03:37:09 | MASTER-OAGH | (22h 18m 30.52s , +65d 39m 41.5s) | C | 60 | 17.0 | 4354 | 2026-07-03 03:37:09 | MASTER-OAGH | (22h 32m 37.85s , +65d 00m 33.9s) | C | 60 | 17.3 | 4430 | 2026-07-03 03:38:25 | MASTER-OAGH | (22h 18m 28.10s , +65d 40m 16.0s) | C | 60 | 17.0 | 4430 | 2026-07-03 03:38:25 | MASTER-OAGH | (22h 32m 35.76s , +65d 01m 08.8s) | C | 60 | 17.4 | 6859 | 2026-07-03 04:18:54 | MASTER-OAGH | (22h 12m 20.69s , +67d 31m 22.6s) | C | 60 | 17.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45068. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43281] Fermi GRB 260703A: Global MASTER-Net observations report
by GCN Circulars 03 Jul '26

03 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45067 SUBJECT: Fermi GRB 260703A: Global MASTER-Net observations report DATE: 26/07/03 04:32:19 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAGH robotic telescope [1] located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 260703A ( Fermi GBM team, GCN 45066) errorbox 4679 sec after notice time and 4712 sec after trigger time at 2026-07-03 03:33:19 UT, with upper limit up to 18.7 mag. Observations started at twilight. The observations began at zenith distance = 72 deg. The sun altitude is -12.7 deg. The galactic latitude b = 2 deg., longitude l = 113 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3412712 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 4742 | 2026-07-03 03:33:19 | MASTER-OAGH | (22h 55m 39.05s , +66d 56m 42.8s) | C | 60 | 16.9 | 4742 | 2026-07-03 03:33:19 | MASTER-OAGH | (22h 40m 24.15s , +67d 36m 09.7s) | C | 60 | 16.4 | 4815 | 2026-07-03 03:34:32 | MASTER-OAGH | (22h 55m 44.27s , +66d 55m 36.7s) | C | 60 | 17.0 | 4815 | 2026-07-03 03:34:32 | MASTER-OAGH | (22h 40m 30.26s , +67d 35m 03.6s) | C | 60 | 16.6 | 4891 | 2026-07-03 03:35:48 | MASTER-OAGH | (23h 55m 18.75s , +68d 50m 07.3s) | C | 60 | 17.2 | 4891 | 2026-07-03 03:35:48 | MASTER-OAGH | (23h 38m 45.84s , +69d 30m 09.3s) | C | 60 | 16.7 | 4972 | 2026-07-03 03:37:09 | MASTER-OAGH | (22h 18m 30.52s , +65d 39m 41.5s) | C | 60 | 17.0 | 4972 | 2026-07-03 03:37:09 | MASTER-OAGH | (22h 32m 37.85s , +65d 00m 33.9s) | C | 60 | 17.3 | 5048 | 2026-07-03 03:38:25 | MASTER-OAGH | (22h 18m 28.10s , +65d 40m 16.0s) | C | 60 | 17.0 | 5048 | 2026-07-03 03:38:25 | MASTER-OAGH | (22h 32m 35.76s , +65d 01m 08.8s) | C | 60 | 17.4 | 7477 | 2026-07-03 04:18:54 | MASTER-OAGH | (22h 27m 21.10s , +66d 52m 48.7s) | C | 60 | 18.5 | 7477 | 2026-07-03 04:18:54 | MASTER-OAGH | (22h 12m 20.69s , +67d 31m 22.6s) | C | 60 | 17.8 | 7552 | 2026-07-03 04:20:09 | MASTER-OAGH | (23h 26m 37.26s , +70d 41m 38.4s) | C | 60 | 18.6 | 7552 | 2026-07-03 04:20:09 | MASTER-OAGH | (23h 08m 47.46s , +71d 21m 01.8s) | C | 60 | 18.0 | 7635 | 2026-07-03 04:21:31 | MASTER-OAGH | (00h 00m 28.54s , +70d 44m 10.6s) | C | 60 | 18.5 | 7635 | 2026-07-03 04:21:31 | MASTER-OAGH | (23h 42m 37.15s , +71d 23m 51.5s) | C | 60 | 17.8 | 7710 | 2026-07-03 04:22:47 | MASTER-OAGH | (22h 52m 44.70s , +70d 41m 44.6s) | C | 60 | 18.7 | 7784 | 2026-07-03 04:24:01 | MASTER-OAGH | (22h 52m 44.99s , +70d 41m 43.6s) | C | 60 | 18.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45067. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43280] GRB 260703A: Fermi GBM Final Localization
by GCN Circulars 03 Jul '26

03 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45066 SUBJECT: GRB 260703A: Fermi GBM Final Localization DATE: 26/07/03 03:47:10 GMT FROM: Matt Godwin <msg0028(a)uah.edu> The Fermi GBM team reports the detection of a likely SHORT GRB "At 02:14:47.19 UT on 03 July 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260703A (trigger 804737692/260703094). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 350.51, Dec = 63.36 (J2000 degrees, equivalent to J2000 23h 22m, +63d 21'), with a statistical uncertainty of 6.72 degrees. The angle from the Fermi LAT boresight is 29 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260703094/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260703094/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260703094/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/45066. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43279] GRB 260610B: VLA detection
by GCN Circulars 02 Jul '26

02 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45065 SUBJECT: GRB 260610B: VLA detection DATE: 26/07/02 20:07:05 GMT FROM: Tanmoy Laskar at U of Utah <tanmoylaskar(a)gmail.com> T. Laskar (Utah), B. P. Gompertz (Birmingham), G. E. Anderson (Curtin), A. Levan (Radboud and Warwick), Daniele Malesani (DAWN/NBI and Radboud), Steve Schulze (Weizmann), Nial Tanvir (Leicester), A. J. van der Horst (GWU) report on behalf of a larger collaboration: “We observed GRB 260610B (Fermi GBM team, GCN 44891; O'Neill et al., GCN 44903) with the Karl G. Jansky Very Large Array (VLA) at multiple frequencies beginning on 2026 June 13 at 07:23 UT (2.89 days after the burst). In preliminary analysis, we detect the radio counterpart (Laskar et al., GCN 44941) at 9 GHz with a flux density of ~ 0.4mJy at the position: RA(J2000) = 14:32:38.25 +/- 0.01” Dec(J2000) = 27:00:17.64 +/- 0.01” This is consistent with the optical position (O'Neill et al., GCN 44903) and radio position (Laskar et al., GCN 44941). Further observations are planned. We thank the VLA staff for scheduling and executing these observations.” View this GCN Circular online at https://gcn.nasa.gov/circulars/45065. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43278] GRB 260623A: Glowbug gamma-ray detection
by GCN Circulars 02 Jul '26

02 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45064 SUBJECT: GRB 260623A: Glowbug gamma-ray detection DATE: 26/07/02 13:47:17 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 260623A, which was also detected by Fermi/GBM (GCN 45028). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-06-23 12:56:46.520 with a duration of 4.1 s and a total significance of about 16.8 sigma. The light curve comprises a single peak. The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/45064. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43277] GRB 260614B: ATCA Radio Upper Limits
by GCN Circulars 01 Jul '26

01 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45063 SUBJECT: GRB 260614B: ATCA Radio Upper Limits DATE: 26/07/01 14:14:22 GMT FROM: Sarah Chastain at Texas Tech University <sarahichastain(a)gmail.com> S. I. Chastain (TTU), G. E. Anderson (CSIRO), S. Ryder (Macquarie), A. Gulati (USyd), A. J. van der Horst (GWU), J. K. Leung (UofT/HUJI), and L. Rhodes (TSI/McGill) on behalf of the ATCA PanRadio GRB collaboration: We observed the long GRB 260614B detected by SVOM (SVOM Team, GCN 44938) and Fermi-GBM (Fermi GBM Team, GCN 44937) with the Australia Telescope Compact Array (ATCA) 6.4 and 11.5 days post-burst. No radio source was detected within the SVOM VT localization region (SVOM Team, 44939). At 8 GHz we find 3-sigma upper limits of 27 and 48 microJy/beam, at 6.4 and 11.5 days post-burst respectively. We thank the CSIRO Space and Astronomy staff for supporting these observations. We acknowledge the Gomeroi people as the traditional owners of the Observatory site. The Australia Telescope Compact Array is part of the Australia Telescope National Facility (https://ror.org/05qajvd42) which is funded by the Australian Government for operation as a National Facility managed by CSIRO. View this GCN Circular online at https://gcn.nasa.gov/circulars/45063. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43276] Fermi trigger No 804552016: Global MASTER-Net observations report
by GCN Circulars 01 Jul '26

01 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45061 SUBJECT: Fermi trigger No 804552016: Global MASTER-Net observations report DATE: 26/07/01 04:03:47 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB260630.94 (trigger No 804552016,12h 45m 31.92s , -37d 28m 01.2s, R=50) errorbox 1803 sec after notice time and 1868 sec after trigger time at 2026-06-30 23:11:19 UT, with upper limit up to 19.9 mag. The observations began at zenith distance = 13 deg. The sun altitude is -18.4 deg. MASTER-OAGH robotic telescope located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB260630.94 errorbox 17793 sec after notice time and 17858 sec after trigger time at 2026-07-01 03:37:49 UT, with upper limit up to 18.5 mag. Observations started at twilight. The observations began at zenith distance = 56 deg. The sun altitude is -13.4 deg. The galactic latitude b = 25 deg., longitude l = 302 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3408638 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1898 | 2026-06-30 23:11:19 | MASTER-OAFA | (12h 11m 25.61s , -30d 50m 47.7s) | C | 60 | 19.5 | 1958 | 2026-06-30 23:11:19 | MASTER-OAFA | (12h 11m 25.61s , -30d 50m 47.8s) | C | 180 | 19.9 | Coadd 1978 | 2026-06-30 23:12:39 | MASTER-OAFA | (12h 11m 31.14s , -30d 50m 34.0s) | C | 60 | 19.4 | 2059 | 2026-06-30 23:14:00 | MASTER-OAFA | (12h 11m 28.06s , -30d 49m 04.0s) | C | 60 | 19.4 | 2138 | 2026-06-30 23:15:19 | MASTER-OAFA | (12h 11m 28.19s , -30d 50m 41.2s) | C | 60 | 19.3 | 2216 | 2026-06-30 23:16:37 | MASTER-OAFA | (12h 11m 32.25s , -30d 48m 51.7s) | C | 60 | 19.2 | 2294 | 2026-06-30 23:17:55 | MASTER-OAFA | (12h 02m 07.33s , -30d 49m 49.7s) | C | 60 | 19.0 | 2354 | 2026-06-30 23:17:55 | MASTER-OAFA | (12h 02m 07.33s , -30d 49m 49.7s) | C | 180 | 19.0 | Coadd 2372 | 2026-06-30 23:19:13 | MASTER-OAFA | (12h 11m 24.61s , -30d 48m 48.1s) | C | 60 | 18.9 | 2448 | 2026-06-30 23:20:29 | MASTER-OAFA | (12h 02m 12.98s , -30d 49m 50.1s) | C | 60 | 18.9 | 2749 | 2026-06-30 23:25:30 | MASTER-OAFA | (12h 58m 02.91s , -08d 06m 38.4s) | C | 60 | 19.1 | 2809 | 2026-06-30 23:25:30 | MASTER-OAFA | (12h 58m 02.90s , -08d 06m 38.4s) | C | 180 | 19.6 | Coadd 2826 | 2026-06-30 23:26:46 | MASTER-OAFA | (12h 58m 02.37s , -08d 08m 12.8s) | C | 60 | 19.0 | 2904 | 2026-06-30 23:28:05 | MASTER-OAFA | (12h 58m 04.68s , -08d 06m 41.8s) | C | 60 | 19.1 | 2980 | 2026-06-30 23:29:21 | MASTER-OAFA | (13h 06m 04.75s , -08d 07m 00.9s) | C | 60 | 19.0 | 3040 | 2026-06-30 23:29:21 | MASTER-OAFA | (13h 06m 04.74s , -08d 07m 00.9s) | C | 180 | 19.0 | Coadd 3134 | 2026-06-30 23:31:55 | MASTER-OAFA | (12h 58m 04.43s , -08d 07m 27.2s) | C | 60 | 19.0 | 3194 | 2026-06-30 23:31:55 | MASTER-OAFA | (12h 58m 04.43s , -08d 07m 27.2s) | C | 180 | 19.4 | Coadd 3212 | 2026-06-30 23:33:12 | MASTER-OAFA | (12h 57m 59.16s , -08d 08m 30.6s) | C | 60 | 18.8 | 3288 | 2026-06-30 23:34:28 | MASTER-OAFA | (13h 06m 11.15s , -08d 08m 08.0s) | C | 60 | 18.8 | 3364 | 2026-06-30 23:35:44 | MASTER-OAFA | (12h 58m 00.86s , -08d 06m 45.7s) | C | 60 | 18.8 | 3708 | 2026-06-30 23:41:28 | MASTER-OAFA | (13h 29m 34.56s , -32d 43m 04.8s) | C | 60 | 19.4 | 3768 | 2026-06-30 23:41:28 | MASTER-OAFA | (13h 29m 34.56s , -32d 43m 04.8s) | C | 180 | 19.7 | Coadd 3784 | 2026-06-30 23:42:45 | MASTER-OAFA | (13h 29m 35.05s , -32d 44m 23.8s) | C | 60 | 19.4 | 3862 | 2026-06-30 23:44:02 | MASTER-OAFA | (13h 29m 38.07s , -32d 43m 17.3s) | C | 60 | 19.4 | 3939 | 2026-06-30 23:45:20 | MASTER-OAFA | (13h 39m 02.97s , -32d 44m 06.5s) | C | 60 | 19.3 | 3999 | 2026-06-30 23:45:20 | MASTER-OAFA | (13h 39m 02.97s , -32d 44m 06.5s) | C | 180 | 19.6 | Coadd 4017 | 2026-06-30 23:46:38 | MASTER-OAFA | (13h 39m 02.76s , -32d 43m 06.1s) | C | 60 | 19.2 | 4094 | 2026-06-30 23:47:55 | MASTER-OAFA | (13h 39m 07.91s , -32d 44m 05.9s) | C | 60 | 19.3 | 4172 | 2026-06-30 23:49:13 | MASTER-OAFA | (13h 29m 32.87s , -32d 44m 51.7s) | C | 60 | 19.4 | 4232 | 2026-06-30 23:49:13 | MASTER-OAFA | (13h 29m 32.86s , -32d 44m 51.7s) | C | 180 | 19.3 | Coadd 4250 | 2026-06-30 23:50:30 | MASTER-OAFA | (13h 39m 08.83s , -32d 44m 50.3s) | C | 60 | 19.2 | 4310 | 2026-06-30 23:50:30 | MASTER-OAFA | (13h 39m 08.81s , -32d 44m 50.5s) | C | 180 | 19.1 | Coadd 4328 | 2026-06-30 23:51:49 | MASTER-OAFA | (13h 29m 36.06s , -32d 43m 17.9s) | C | 60 | 19.1 | 4411 | 2026-06-30 23:53:12 | MASTER-OAFA | (12h 11m 32.66s , -30d 50m 22.0s) | C | 60 | 19.0 | 4471 | 2026-06-30 23:53:12 | MASTER-OAFA | (12h 11m 32.66s , -30d 50m 22.1s) | C | 180 | 19.6 | Coadd 4488 | 2026-06-30 23:54:29 | MASTER-OAFA | (12h 11m 34.87s , -30d 48m 42.2s) | C | 60 | 18.9 | 4564 | 2026-06-30 23:55:44 | MASTER-OAFA | (12h 11m 29.95s , -30d 49m 39.6s) | C | 60 | 19.0 | 4642 | 2026-06-30 23:57:03 | MASTER-OAFA | (12h 11m 30.45s , -30d 48m 40.6s) | C | 60 | 18.9 | 4702 | 2026-06-30 23:57:03 | MASTER-OAFA | (12h 11m 30.45s , -30d 48m 40.6s) | C | 180 | 19.0 | Coadd 4717 | 2026-06-30 23:58:18 | MASTER-OAFA | (12h 11m 37.03s , -30d 49m 41.0s) | C | 60 | 19.0 | 4838 | 2026-07-01 00:00:19 | MASTER-OAFA | (12h 02m 16.96s , -30d 53m 15.9s) | C | 60 | 19.1 | 4913 | 2026-07-01 00:01:34 | MASTER-OAFA | (12h 02m 22.35s , -30d 52m 45.4s) | C | 60 | 19.1 | 4973 | 2026-07-01 00:01:34 | MASTER-OAFA | (12h 02m 22.35s , -30d 52m 45.4s) | C | 180 | 19.8 | Coadd 4992 | 2026-07-01 00:02:53 | MASTER-OAFA | (12h 02m 19.87s , -30d 51m 37.4s) | C | 60 | 19.2 | 5069 | 2026-07-01 00:04:10 | MASTER-OAFA | (12h 02m 19.89s , -30d 52m 56.2s) | C | 60 | 19.1 | 5147 | 2026-07-01 00:05:27 | MASTER-OAFA | (12h 02m 22.84s , -30d 51m 33.7s) | C | 60 | 19.1 | 5229 | 2026-07-01 00:06:49 | MASTER-OAFA | (13h 06m 33.42s , -08d 06m 03.6s) | C | 60 | 19.3 | 5307 | 2026-07-01 00:08:08 | MASTER-OAFA | (13h 06m 33.42s , -08d 05m 01.6s) | C | 60 | 19.3 | 5367 | 2026-07-01 00:08:08 | MASTER-OAFA | (13h 06m 33.42s , -08d 05m 01.6s) | C | 180 | 19.7 | Coadd 5385 | 2026-07-01 00:09:26 | MASTER-OAFA | (13h 06m 39.16s , -08d 05m 59.4s) | C | 60 | 19.3 | 5461 | 2026-07-01 00:10:42 | MASTER-OAFA | (13h 06m 32.29s , -08d 06m 57.7s) | C | 60 | 19.2 | 5538 | 2026-07-01 00:11:58 | MASTER-OAFA | (13h 06m 38.41s , -08d 06m 40.7s) | C | 60 | 19.1 | 5615 | 2026-07-01 00:13:16 | MASTER-OAFA | (12h 58m 30.86s , -08d 05m 10.5s) | C | 60 | 19.0 | 5675 | 2026-07-01 00:13:16 | MASTER-OAFA | (12h 58m 30.86s , -08d 05m 10.6s) | C | 180 | 19.5 | Coadd 5694 | 2026-07-01 00:14:35 | MASTER-OAFA | (12h 58m 30.88s , -08d 06m 11.4s) | C | 60 | 19.1 | 5772 | 2026-07-01 00:15:53 | MASTER-OAFA | (12h 58m 34.85s , -08d 04m 57.2s) | C | 60 | 19.0 | 5847 | 2026-07-01 00:17:08 | MASTER-OAFA | (12h 58m 28.36s , -08d 05m 36.1s) | C | 60 | 19.1 | 5925 | 2026-07-01 00:18:25 | MASTER-OAFA | (12h 58m 27.98s , -08d 04m 34.8s) | C | 60 | 19.0 | 6062 | 2026-07-01 00:20:43 | MASTER-OAFA | (13h 39m 16.94s , -32d 47m 14.9s) | C | 60 | 19.4 | 6142 | 2026-07-01 00:22:02 | MASTER-OAFA | (13h 39m 11.65s , -32d 48m 11.8s) | C | 60 | 19.4 | 6218 | 2026-07-01 00:23:19 | MASTER-OAFA | (13h 39m 11.42s , -32d 47m 10.5s) | C | 60 | 19.3 | 6278 | 2026-07-01 00:23:19 | MASTER-OAFA | (13h 39m 11.42s , -32d 47m 10.5s) | C | 180 | 19.7 | Coadd 6295 | 2026-07-01 00:24:35 | MASTER-OAFA | (13h 39m 19.09s , -32d 48m 09.4s) | C | 60 | 19.3 | 6371 | 2026-07-01 00:25:51 | MASTER-OAFA | (13h 39m 12.39s , -32d 49m 07.8s) | C | 60 | 19.4 | 6448 | 2026-07-01 00:27:09 | MASTER-OAFA | (13h 29m 47.65s , -32d 48m 43.5s) | C | 60 | 19.3 | 6524 | 2026-07-01 00:28:25 | MASTER-OAFA | (13h 29m 45.29s , -32d 47m 10.8s) | C | 60 | 19.3 | 6584 | 2026-07-01 00:28:25 | MASTER-OAFA | (13h 29m 45.28s , -32d 47m 10.9s) | C | 180 | 19.8 | Coadd 6601 | 2026-07-01 00:29:41 | MASTER-OAFA | (13h 29m 45.34s , -32d 48m 40.8s) | C | 60 | 19.3 | 6676 | 2026-07-01 00:30:57 | MASTER-OAFA | (13h 29m 47.61s , -32d 46m 47.9s) | C | 60 | 19.3 | 6754 | 2026-07-01 00:32:14 | MASTER-OAFA | (13h 29m 42.31s , -32d 47m 40.8s) | C | 60 | 19.3 | 6814 | 2026-07-01 00:32:14 | MASTER-OAFA | (13h 29m 42.31s , -32d 47m 40.8s) | C | 180 | 19.6 | Coadd 6834 | 2026-07-01 00:33:35 | MASTER-OAFA | (12h 11m 36.74s , -30d 51m 08.0s) | C | 60 | 19.1 | 6925 | 2026-07-01 00:35:06 | MASTER-OAFA | (13h 30m 52.07s , -30d 52m 56.4s) | C | 60 | 19.3 | 6985 | 2026-07-01 00:35:06 | MASTER-OAFA | (13h 30m 52.06s , -30d 52m 56.4s) | C | 180 | 19.8 | Coadd 7001 | 2026-07-01 00:36:22 | MASTER-OAFA | (13h 40m 11.04s , -30d 54m 55.4s) | C | 60 | 19.4 | 7061 | 2026-07-01 00:36:22 | MASTER-OAFA | (13h 40m 11.04s , -30d 54m 55.5s) | C | 180 | 19.6 | Coadd 7081 | 2026-07-01 00:37:42 | MASTER-OAFA | (13h 30m 55.07s , -30d 52m 47.7s) | C | 60 | 19.3 | 7159 | 2026-07-01 00:39:00 | MASTER-OAFA | (13h 40m 08.36s , -30d 53m 55.0s) | C | 60 | 19.4 | 7235 | 2026-07-01 00:40:16 | MASTER-OAFA | (13h 30m 49.15s , -30d 52m 34.4s) | C | 60 | 19.4 | 7327 | 2026-07-01 00:41:48 | MASTER-OAFA | (13h 51m 10.27s , -38d 31m 01.8s) | C | 60 | 19.1 | 7387 | 2026-07-01 00:41:48 | MASTER-OAFA | (13h 51m 10.27s , -38d 31m 01.8s) | C | 180 | 19.4 | Coadd 7405 | 2026-07-01 00:43:05 | MASTER-OAFA | (14h 01m 25.47s , -38d 29m 55.5s) | C | 60 | 18.9 | 7465 | 2026-07-01 00:43:05 | MASTER-OAFA | (14h 01m 25.47s , -38d 29m 55.5s) | C | 180 | 19.3 | Coadd 7481 | 2026-07-01 00:44:22 | MASTER-OAFA | (13h 51m 07.32s , -38d 30m 18.7s) | C | 60 | 19.0 | 7558 | 2026-07-01 00:45:39 | MASTER-OAFA | (14h 01m 19.65s , -38d 29m 42.0s) | C | 60 | 18.9 | 7641 | 2026-07-01 00:47:01 | MASTER-OAFA | (13h 51m 14.42s , -38d 30m 16.4s) | C | 60 | 19.1 | 7739 | 2026-07-01 00:48:39 | MASTER-OAFA | (13h 51m 13.52s , -38d 30m 14.6s) | C | 60 | 19.1 | 7799 | 2026-07-01 00:48:39 | MASTER-OAFA | (13h 51m 13.52s , -38d 30m 14.6s) | C | 180 | 19.4 | Coadd 7816 | 2026-07-01 00:49:57 | MASTER-OAFA | (14h 01m 21.32s , -38d 31m 38.0s) | C | 60 | 18.9 | 7895 | 2026-07-01 00:51:15 | MASTER-OAFA | (13h 51m 13.92s , -38d 31m 00.1s) | C | 60 | 19.1 | 7972 | 2026-07-01 00:52:32 | MASTER-OAFA | (14h 01m 24.56s , -38d 30m 01.9s) | C | 60 | 18.9 | 8032 | 2026-07-01 00:52:32 | MASTER-OAFA | (14h 01m 24.56s , -38d 30m 01.9s) | C | 180 | 19.3 | Coadd 8050 | 2026-07-01 00:53:51 | MASTER-OAFA | (13h 51m 12.09s , -38d 30m 58.1s) | C | 60 | 19.1 | 8134 | 2026-07-01 00:55:14 | MASTER-OAFA | (13h 29m 00.78s , -17d 35m 39.1s) | C | 60 | 19.1 | 8194 | 2026-07-01 00:55:14 | MASTER-OAFA | (13h 29m 00.77s , -17d 35m 39.2s) | C | 180 | 19.7 | Coadd 8210 | 2026-07-01 00:56:31 | MASTER-OAFA | (13h 37m 24.55s , -17d 34m 52.7s) | C | 60 | 19.0 | 8288 | 2026-07-01 00:57:49 | MASTER-OAFA | (13h 29m 07.73s , -17d 35m 36.1s) | C | 60 | 19.1 | 8366 | 2026-07-01 00:59:07 | MASTER-OAFA | (13h 37m 23.96s , -17d 36m 49.7s) | C | 60 | 19.0 | 8444 | 2026-07-01 01:00:24 | MASTER-OAFA | (13h 29m 06.38s , -17d 36m 28.6s) | C | 60 | 18.9 | 8525 | 2026-07-01 01:01:45 | MASTER-OAFA | (13h 39m 18.46s , -32d 46m 40.9s) | C | 60 | 19.2 | 8585 | 2026-07-01 01:01:45 | MASTER-OAFA | (13h 39m 18.46s , -32d 46m 40.9s) | C | 180 | 19.6 | Coadd 8600 | 2026-07-01 01:03:01 | MASTER-OAFA | (13h 39m 18.53s , -32d 48m 05.0s) | C | 60 | 19.3 | 8675 | 2026-07-01 01:04:16 | MASTER-OAFA | (13h 39m 22.21s , -32d 46m 34.7s) | C | 60 | 19.2 | 8755 | 2026-07-01 01:05:35 | MASTER-OAFA | (13h 39m 16.17s , -32d 47m 27.7s) | C | 60 | 19.3 | 8815 | 2026-07-01 01:05:35 | MASTER-OAFA | (13h 39m 16.17s , -32d 47m 27.8s) | C | 180 | 19.6 | Coadd 8831 | 2026-07-01 01:06:52 | MASTER-OAFA | (13h 39m 16.64s , -32d 46m 26.5s) | C | 60 | 19.4 | 8913 | 2026-07-01 01:08:14 | MASTER-OAFA | (13h 29m 51.36s , -32d 47m 09.4s) | C | 60 | 19.2 | 8991 | 2026-07-01 01:09:32 | MASTER-OAFA | (13h 29m 45.00s , -32d 48m 08.2s) | C | 60 | 19.1 | 9067 | 2026-07-01 01:10:47 | MASTER-OAFA | (13h 29m 50.84s , -32d 47m 47.2s) | C | 60 | 19.2 | 9127 | 2026-07-01 01:10:47 | MASTER-OAFA | (13h 29m 50.84s , -32d 47m 47.2s) | C | 180 | 19.7 | Coadd 9145 | 2026-07-01 01:12:05 | MASTER-OAFA | (13h 29m 48.76s , -32d 46m 34.4s) | C | 60 | 19.2 | 9223 | 2026-07-01 01:13:24 | MASTER-OAFA | (13h 29m 48.84s , -32d 47m 47.3s) | C | 60 | 19.0 | 9302 | 2026-07-01 01:14:43 | MASTER-OAFA | (13h 40m 17.47s , -30d 52m 37.2s) | C | 60 | 19.1 | 9381 | 2026-07-01 01:16:02 | MASTER-OAFA | (13h 40m 11.75s , -30d 53m 21.5s) | C | 60 | 19.1 | 9441 | 2026-07-01 01:16:02 | MASTER-OAFA | (13h 40m 11.75s , -30d 53m 21.5s) | C | 180 | 19.6 | Coadd 9459 | 2026-07-01 01:17:20 | MASTER-OAFA | (13h 40m 10.41s , -30d 52m 20.2s) | C | 60 | 19.1 | 9535 | 2026-07-01 01:18:36 | MASTER-OAFA | (13h 30m 58.31s , -30d 53m 04.4s) | C | 60 | 19.0 | 9595 | 2026-07-01 01:18:36 | MASTER-OAFA | (13h 30m 58.30s , -30d 53m 04.4s) | C | 180 | 19.6 | Coadd 9618 | 2026-07-01 01:19:59 | MASTER-OAFA | (13h 30m 51.91s , -30d 54m 03.6s) | C | 60 | 19.0 | 9693 | 2026-07-01 01:21:14 | MASTER-OAFA | (13h 30m 58.11s , -30d 53m 41.0s) | C | 60 | 19.1 | 9772 | 2026-07-01 01:22:33 | MASTER-OAFA | (14h 01m 27.59s , -38d 29m 07.2s) | C | 60 | 18.8 | 9849 | 2026-07-01 01:23:50 | MASTER-OAFA | (14h 01m 27.70s , -38d 30m 30.8s) | C | 60 | 18.8 | 9928 | 2026-07-01 01:25:08 | MASTER-OAFA | (14h 01m 30.73s , -38d 29m 04.0s) | C | 60 | 18.8 | 9988 | 2026-07-01 01:25:08 | MASTER-OAFA | (14h 01m 30.72s , -38d 29m 04.0s) | C | 180 | 19.4 | Coadd 10007 | 2026-07-01 01:26:27 | MASTER-OAFA | (13h 51m 12.13s , -38d 29m 36.3s) | C | 60 | 18.9 | 10067 | 2026-07-01 01:26:27 | MASTER-OAFA | (13h 51m 12.13s , -38d 29m 36.3s) | C | 180 | 19.3 | Coadd 10082 | 2026-07-01 01:27:43 | MASTER-OAFA | (13h 51m 12.62s , -38d 28m 35.1s) | C | 60 | 18.8 | 10162 | 2026-07-01 01:29:02 | MASTER-OAFA | (13h 51m 17.78s , -38d 29m 34.3s) | C | 60 | 18.8 | 10240 | 2026-07-01 01:30:21 | MASTER-OAFA | (14h 01m 25.20s , -38d 30m 53.5s) | C | 60 | 18.8 | 10317 | 2026-07-01 01:31:38 | MASTER-OAFA | (14h 01m 31.41s , -38d 30m 29.4s) | C | 60 | 19.0 | 10394 | 2026-07-01 01:32:55 | MASTER-OAFA | (14h 01m 28.69s , -38d 29m 07.7s) | C | 60 | 19.0 | 10454 | 2026-07-01 01:32:55 | MASTER-OAFA | (14h 01m 28.69s , -38d 29m 07.7s) | C | 180 | 19.1 | Coadd 10474 | 2026-07-01 01:34:14 | MASTER-OAFA | (13h 51m 16.14s , -38d 30m 06.1s) | C | 60 | 19.0 | 10534 | 2026-07-01 01:34:14 | MASTER-OAFA | (13h 51m 16.14s , -38d 30m 06.1s) | C | 180 | 19.4 | Coadd 10549 | 2026-07-01 01:35:30 | MASTER-OAFA | (13h 51m 20.22s , -38d 28m 38.4s) | C | 60 | 19.0 | 10628 | 2026-07-01 01:36:48 | MASTER-OAFA | (13h 51m 13.53s , -38d 29m 29.0s) | C | 60 | 19.0 | 10711 | 2026-07-01 01:38:11 | MASTER-OAFA | (13h 39m 17.94s , -32d 48m 04.9s) | C | 60 | 19.0 | 10785 | 2026-07-01 01:39:25 | MASTER-OAFA | (13h 39m 24.50s , -32d 48m 00.2s) | C | 60 | 19.0 | 10845 | 2026-07-01 01:39:25 | MASTER-OAFA | (13h 39m 24.49s , -32d 48m 00.2s) | C | 180 | 19.5 | Coadd 10861 | 2026-07-01 01:40:42 | MASTER-OAFA | (13h 39m 21.37s , -32d 46m 32.7s) | C | 60 | 19.0 | 10938 | 2026-07-01 01:41:59 | MASTER-OAFA | (13h 39m 21.43s , -32d 47m 37.2s) | C | 60 | 19.0 | 11016 | 2026-07-01 01:43:17 | MASTER-OAFA | (13h 39m 25.10s , -32d 46m 17.0s) | C | 60 | 19.0 | 11095 | 2026-07-01 01:44:36 | MASTER-OAFA | (13h 59m 55.70s , -23d 16m 44.9s) | C | 60 | 19.1 | 11155 | 2026-07-01 01:44:36 | MASTER-OAFA | (13h 59m 55.70s , -23d 16m 44.9s) | C | 180 | 19.5 | Coadd 11173 | 2026-07-01 01:45:54 | MASTER-OAFA | (14h 08m 44.02s , -23d 18m 00.3s) | C | 60 | 19.0 | 11248 | 2026-07-01 01:47:09 | MASTER-OAFA | (13h 59m 56.14s , -23d 18m 42.7s) | C | 60 | 18.9 | 11328 | 2026-07-01 01:48:29 | MASTER-OAFA | (14h 00m 01.59s , -23d 18m 36.0s) | C | 60 | 18.7 | 11405 | 2026-07-01 01:49:46 | MASTER-OAFA | (13h 59m 59.10s , -23d 16m 43.4s) | C | 60 | 18.3 | 11481 | 2026-07-01 01:51:01 | MASTER-OAFA | (14h 08m 41.35s , -23d 18m 33.7s) | C | 60 | 19.1 | 11557 | 2026-07-01 01:52:18 | MASTER-OAFA | (14h 00m 02.44s , -23d 16m 56.2s) | C | 60 | 18.9 | 11634 | 2026-07-01 01:53:35 | MASTER-OAFA | (13h 40m 14.42s , -30d 52m 59.4s) | C | 60 | 19.2 | 11711 | 2026-07-01 01:54:52 | MASTER-OAFA | (13h 40m 13.42s , -30d 51m 59.2s) | C | 60 | 18.5 | 11789 | 2026-07-01 01:56:09 | MASTER-OAFA | (13h 40m 19.61s , -30d 52m 59.3s) | C | 60 | 18.5 | 11869 | 2026-07-01 01:57:30 | MASTER-OAFA | (14h 01m 34.40s , -38d 30m 30.0s) | C | 60 | 18.4 | 11947 | 2026-07-01 01:58:48 | MASTER-OAFA | (14h 01m 30.97s , -38d 28m 35.6s) | C | 60 | 18.8 | 12023 | 2026-07-01 02:00:04 | MASTER-OAFA | (14h 01m 31.06s , -38d 30m 30.1s) | C | 60 | 19.0 | 12083 | 2026-07-01 02:00:04 | MASTER-OAFA | (14h 01m 31.06s , -38d 30m 30.1s) | C | 180 | 19.4 | Coadd 12097 | 2026-07-01 02:01:18 | MASTER-OAFA | (13h 51m 20.96s , -38d 28m 15.8s) | C | 60 | 19.1 | 12157 | 2026-07-01 02:01:18 | MASTER-OAFA | (13h 51m 20.96s , -38d 28m 15.8s) | C | 180 | 19.4 | Coadd 12175 | 2026-07-01 02:02:36 | MASTER-OAFA | (13h 51m 16.39s , -38d 29m 13.8s) | C | 60 | 19.1 | 12254 | 2026-07-01 02:03:55 | MASTER-OAFA | (13h 51m 16.50s , -38d 28m 13.3s) | C | 60 | 19.1 | 12332 | 2026-07-01 02:05:13 | MASTER-OAFA | (14h 01m 35.46s , -38d 29m 29.3s) | C | 60 | 19.1 | 12411 | 2026-07-01 02:06:31 | MASTER-OAFA | (14h 01m 29.11s , -38d 30m 28.6s) | C | 60 | 19.1 | 12487 | 2026-07-01 02:07:47 | MASTER-OAFA | (14h 01m 34.26s , -38d 30m 15.1s) | C | 60 | 19.1 | 12565 | 2026-07-01 02:09:05 | MASTER-OAFA | (13h 51m 19.17s , -38d 28m 34.1s) | C | 60 | 19.1 | 12625 | 2026-07-01 02:09:05 | MASTER-OAFA | (13h 51m 19.16s , -38d 28m 34.0s) | C | 180 | 19.4 | Coadd 12643 | 2026-07-01 02:10:23 | MASTER-OAFA | (13h 51m 19.26s , -38d 30m 06.1s) | C | 60 | 19.1 | 12720 | 2026-07-01 02:11:41 | MASTER-OAFA | (13h 51m 22.61s , -38d 28m 15.2s) | C | 60 | 19.1 | 12796 | 2026-07-01 02:12:57 | MASTER-OAFA | (13h 51m 16.98s , -38d 29m 10.7s) | C | 60 | 19.1 | 12873 | 2026-07-01 02:14:14 | MASTER-OAFA | (13h 51m 17.09s , -38d 28m 10.0s) | C | 60 | 19.0 | 12954 | 2026-07-01 02:15:34 | MASTER-OAFA | (14h 26m 33.09s , -19d 31m 23.2s) | C | 60 | 19.4 | 13014 | 2026-07-01 02:15:34 | MASTER-OAFA | (14h 26m 33.08s , -19d 31m 23.2s) | C | 180 | 19.6 | Coadd 13033 | 2026-07-01 02:16:53 | MASTER-OAFA | (14h 35m 09.05s , -19d 31m 09.9s) | C | 60 | 19.2 | 13109 | 2026-07-01 02:18:09 | MASTER-OAFA | (14h 26m 37.10s , -19d 29m 32.6s) | C | 60 | 19.3 | 13289 | 2026-07-01 02:21:10 | MASTER-OAFA | (14h 35m 04.14s , -19d 29m 35.6s) | C | 60 | 19.0 | 13366 | 2026-07-01 02:22:27 | MASTER-OAFA | (14h 26m 39.75s , -19d 30m 17.3s) | C | 60 | 19.1 | 13579 | 2026-07-01 02:25:59 | MASTER-OAFA | (14h 58m 49.12s , -19d 30m 26.3s) | C | 60 | 18.9 | 13639 | 2026-07-01 02:25:59 | MASTER-OAFA | (14h 58m 49.13s , -19d 30m 26.3s) | C | 180 | 19.5 | Coadd 13658 | 2026-07-01 02:27:19 | MASTER-OAFA | (15h 07m 25.10s , -19d 31m 47.1s) | C | 60 | 19.0 | 14356 | 2026-07-01 02:38:57 | MASTER-OAFA | (14h 58m 54.99s , -19d 32m 10.5s) | C | 60 | 19.0 | 14431 | 2026-07-01 02:40:11 | MASTER-OAFA | (15h 07m 27.00s , -19d 31m 12.4s) | C | 60 | 19.0 | 14508 | 2026-07-01 02:41:29 | MASTER-OAFA | (14h 58m 52.88s , -19d 31m 27.7s) | C | 60 | 19.1 | 14661 | 2026-07-01 02:44:02 | MASTER-OAFA | (16h 51m 03.50s , -59d 31m 12.5s) | C | 60 | 18.0 | 14739 | 2026-07-01 02:45:20 | MASTER-OAFA | (17h 06m 44.47s , -59d 32m 36.6s) | C | 60 | 18.1 | 14799 | 2026-07-01 02:45:20 | MASTER-OAFA | (17h 06m 44.46s , -59d 32m 36.6s) | C | 180 | 18.5 | Coadd 14816 | 2026-07-01 02:46:37 | MASTER-OAFA | (17h 06m 44.29s , -59d 31m 36.1s) | C | 60 | 18.1 | 14894 | 2026-07-01 02:47:54 | MASTER-OAFA | (17h 06m 49.03s , -59d 32m 35.6s) | C | 60 | 18.1 | 14972 | 2026-07-01 02:49:13 | MASTER-OAFA | (16h 50m 58.69s , -59d 32m 44.7s) | C | 60 | 18.0 | 15047 | 2026-07-01 02:50:28 | MASTER-OAFA | (16h 51m 03.50s , -59d 32m 19.6s) | C | 60 | 18.0 | 15128 | 2026-07-01 02:51:49 | MASTER-OAFA | (17h 06m 50.12s , -59d 31m 58.9s) | C | 60 | 18.1 | 17948 | 2026-07-01 03:37:49 | MASTER-OAGH | (11h 33m 19.71s , +01d 24m 59.1s) | C | 180 | 17.9 | 17948 | 2026-07-01 03:37:49 | MASTER-OAGH | (11h 31m 57.03s , +01d 57m 36.7s) | C | 180 | 18.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45061. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43275] GRB 260701A: Fermi GBM Final Real-time Localization
by GCN Circulars 01 Jul '26

01 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45060 SUBJECT: GRB 260701A: Fermi GBM Final Real-time Localization DATE: 26/07/01 02:27:30 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 02:16:36 UT on 1 Jul 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260701A (trigger 804565001.437744 / 260701095). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 294.2, Dec = -51.3 (J2000 degrees, equivalent to J2000 19h 36m, -51d 17'), with a statistical uncertainty of 6.7 degrees. The angle from the Fermi LAT boresight is 68.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260701095/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260701095/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260701095/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45060. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43274] Fermi GBM trigger 804552016/260630945 is not a GRB
by GCN Circulars 01 Jul '26

01 Jul '26

TITLE: GCN CIRCULAR NUMBER: 45059 SUBJECT: Fermi GBM trigger 804552016/260630945 is not a GRB DATE: 26/07/01 01:26:30 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 804552016/260630945 at 22:40:11.17 UT on 30 June 2026, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to statistical fluctuations in opposite-facing detectors." View this GCN Circular online at https://gcn.nasa.gov/circulars/45059. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43273] Fermi-LAT Gamma-ray Observations of IceCube-260622A
by GCN Circulars 30 Jun '26

30 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45058 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-260622A DATE: 26/06/30 23:04:48 GMT FROM: Simone Garrappa at Weizmann Institute of Science <simone.garrappa(a)weizmann.ac.il> S. Garrappa (Weizmann Institute of Science), L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg), J. Valverde (Marquette University) and C. Bartolini (University of Trento, INFN Bari) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC260622A neutrino event (GCN 45018) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 2026-06-22 at 15:41:54.81 UTC (T0) with J2000 position RA = 173.36 (+0.5, -0.52) deg, Decl. = 1.34 (+0.58, -0.58) deg, 90% PSF containment. No cataloged >100 MeV gamma-ray sources are located within the 90% IC260622A localization error (4FGL-DR4; The Fourth Fermi-LAT catalog Data Release 4, The Fermi-LAT collaboration 2023, arXiv:2307.12546). In the preliminary list of the upcoming 5FGL catalog (FL16Y, Ballet et al. 2026), we find the gamma-ray source FL16Y 1134.2+0051 within the neutrino 90% PSF containment, at 0.53 deg from the best-fit neutrino position. From a preliminary analysis of Fermi-LAT data integrated on 1 month before T0, the source is significantly detected (> 5 sigma) in gamma-rays. The source is detected with a flux F = (1 +/- 0.3)e-7 ph cm^-2 s^-1 and best-fit power-law index 2.9 +/- 0.2, statistical errors only. A tentative counterpart to FL16Y 1134.2+0051 is the flat-spectrum radio source CRATES J1133+0058 (Healey et al. 2007, ApJS 171 1 61), ~9 arcmin from the Fermi-LAT best-fit localization and within its 68% error. We note that the localization region of IceCube-260622A is very close to the ecliptic; therefore the aforementioned results could be partially contaminated by the emission from the Moon. Time intervals with the Sun in the region of interest have been excluded from the analysis. We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC260622A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC260622A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 2.2e-10 ph cm^-2 s^-1 for ~18-years (2008-08-04 / T0), <1.2e-08 (<8.4e-07) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this source the Fermi-LAT contact person is Simone Garrappa (simone.garrappa at weizmann.ac.il). The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/45058. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43272] EP260628a: EP-FXT follow-up observation
by GCN Circulars 30 Jun '26

30 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45057 SUBJECT: EP260628a: EP-FXT follow-up observation DATE: 26/06/30 02:51:19 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> X. Mao (NAO, CAS), C. Y. Dai (NJU), H. N. Yang, C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of EP260628a (X. Mao et al., GCN 45054) starting at 2026-06-29T06:40:57 (UTC), approximately 13.5 hours after the WXT detection. With an exposure time of 1.5 ks, no significant X-ray source was detected within the 2.8 arcmin radius of the EP-WXT position. The derived 0.5-10 keV upper limit is about 3.7 x 10^(-13) erg cm^-2 s^-1. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45057. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43271] GRB 260629A: Fermi GBM Final Real-time Localization
by GCN Circulars 29 Jun '26

29 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45056 SUBJECT: GRB 260629A: Fermi GBM Final Real-time Localization DATE: 26/06/29 15:19:19 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 15:06:58 UT on 29 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260629A (trigger 804438423.955606 / 260629630). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 146.1, Dec = 70.6 (J2000 degrees, equivalent to J2000 09h 44m, 70d 35'), with a statistical uncertainty of 10.5 degrees. The angle from the Fermi LAT boresight is 49.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260629630/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260629630/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260629630/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45056. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43270] Fermi GRB 260628A: Global MASTER-Net observations report
by GCN Circulars 29 Jun '26

29 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45055 SUBJECT: Fermi GRB 260628A: Global MASTER-Net observations report DATE: 26/06/29 03:33:42 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-OAGH robotic telescope [1] located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 260628A ( Fermi GBM team, GCN 45053) errorbox 19512 sec after notice time and 19564 sec after trigger time at 2026-06-29 03:17:28 UT, with upper limit up to 15.9 mag. Observations started at twilight. The observations began at zenith distance = 81 deg. The sun altitude is -9.9 deg. The galactic latitude b = -26 deg., longitude l = 39 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3405318 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 19595 | 2026-06-29 03:17:28 | MASTER-OAGH | (19h 41m 35.39s , +00d 26m 15.1s) | C | 60 | 14.6 | 19821 | 2026-06-29 03:21:14 | MASTER-OAGH | (19h 41m 18.87s , -01d 27m 54.5s) | C | 60 | 15.0 | 19821 | 2026-06-29 03:21:14 | MASTER-OAGH | (19h 35m 27.78s , -00d 49m 53.7s) | C | 60 | 14.5 | 19901 | 2026-06-29 03:22:35 | MASTER-OAGH | (19h 43m 03.30s , +02d 19m 13.8s) | C | 60 | 15.4 | 20056 | 2026-06-29 03:25:10 | MASTER-OAGH | (19h 47m 54.90s , +02d 57m 54.9s) | C | 60 | 14.9 | 20056 | 2026-06-29 03:25:10 | MASTER-OAGH | (19h 53m 46.15s , +02d 19m 54.0s) | C | 60 | 15.4 | 20137 | 2026-06-29 03:26:30 | MASTER-OAGH | (19h 45m 51.59s , +04d 13m 03.3s) | C | 60 | 15.9 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/45055. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43269] EP260628a: EP-WXT detection of a fast X-ray transient
by GCN Circulars 29 Jun '26

29 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45054 SUBJECT: EP260628a: EP-WXT detection of a fast X-ray transient DATE: 26/06/29 03:22:43 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> X. Mao, H. N. Yang (NAO, CAS), C. Y. Dai(NJU), C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient, designated EP260628a, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient was identified in the telemetry data. The transient started at 2026-06-28T17:08:08 (UTC) and lasted for about 30s, with a peak flux of ~ 7 x 10^(-9) erg cm^-2 s^-1 in 0.5-4 keV. The position of the transient is R.A. = 312.9884 deg, Dec. = -34.3748 (J2000), with an uncertainty radius of 2.8 arcmin in radius (90% confidence level, including both statistical and systematic uncertainties). There are no known X-ray sources in the WXT error circle. The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 4.86×10^20 cm^-2 and a photon index of 0.67 (-0.52/+0.52). The derived average unabsorbed 0.5-4 keV flux is 1.87 (-0.54/+0.71) x 10^(-9) erg cm^-2 s^-1. The uncertainties are at the 90% confidence level for the above parameters. Follow-up observations by EP-FXT will be arranged. Launched on 2024 January 9, Einstein Probe is a space-based X-ray observatory designed to monitor the dynamic X-ray sky and perform rapid follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45054. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43268] GRB 260628A: Fermi GBM Final Real-time Localization
by GCN Circulars 28 Jun '26

28 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45053 SUBJECT: GRB 260628A: Fermi GBM Final Real-time Localization DATE: 26/06/28 22:03:44 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely SHORT GRB At 21:51:24 UT on 28 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260628A (trigger 804376289.020238 / 260628911). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 308.2, Dec = -6.9 (J2000 degrees, equivalent to J2000 20h 32m, -6d 54'), with a statistical uncertainty of 14.3 degrees. The angle from the Fermi LAT boresight is 63.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260628911/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260628911/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260628911/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45053. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43267] The EP-WXT trigger 01709272671 is likely a flaring star
by GCN Circulars 28 Jun '26

28 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45052 SUBJECT: The EP-WXT trigger 01709272671 is likely a flaring star DATE: 26/06/28 02:08:13 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J. P. Chen (SYSU), K. J. Zhang, D. Zhu (YNU), Y. J. Yi (BNU), Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709272671 at the time of 2026-06-27T17:53:04 (UTC), is likely a stellar flare associated with RX J1942.2-2045. The estimated flux of the flare is around 1.6 x 10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 4.8 x 10^(30) erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45052. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43266] EP260626a: further Liverpool Telescope optical upper limits
by GCN Circulars 27 Jun '26

27 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45051 SUBJECT: EP260626a: further Liverpool Telescope optical upper limits DATE: 26/06/27 17:25:38 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek, D. A. Perley (LJMU), report: We observed the field of EP260626a (Chen et al., GCN 45047; Chen et al., GCN 45050) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 8x150s exposures in SDSS r and z filters, starting at 2026-06-27 01:59:23 UT, approximately 20.57 hours after EP trigger. The stacked exposures were subtracted from PanSTARRS reference imaging using custom PSF-matching image subtraction code utilising Swarp, SourceExtractor, and PSFex. We do not detect any new sources in the error EP/WXT region (Chen et al., GCN 45047), including at the position of the uncatalogued X-ray source reported by Chen et al. (GCN 45047), down to 3 sigma upper limits of r> 23.44 and z> 22.94. This is consistent with upper limits from Eyles-Ferris et al. (GCN 45048) and Magnani et al. (GCN 45049). The photometry is in the AB magnitude system, was calibrated using nearby PanSTARRS secondary standards and was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45051. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43265] EP260626a: EP-FXT follow-up observation
by GCN Circulars 27 Jun '26

27 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45050 SUBJECT: EP260626a: EP-FXT follow-up observation DATE: 26/06/27 15:28:42 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J. P. Chen (SYSU), K. J. Zhang, D. Zhu (YNU), W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of EP260626a (J. P. Chen et al., GCN 45047) approximately 10.8 hours after the WXT detection, with an exposure time of 6.1 ks. An uncatalogued X-ray source was detected within the WXT error circle at R.A. = 277.4479, Dec. = 21.2498 (J2000), with a positional uncertainty of 10.0 arcsec (radius, 90% C.L. statistical and systematic). The FXT spectrum can be fitted with an absorbed powerlaw with a hydrogen column density fixed at the Galactic value of 2.04 x 10^21 cm^-2 and a photon index of 2.13 (+0.6, -0.6). The derived unabsorbed 0.5-10 keV flux is approximately 9.3 (+4.5, -2.1) x 10^-14 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. No optical counterpart has been detected (R. A. J. Eyles-Ferris et al., GCN 45048; Francesco Magnani et al., GCN 45049). Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45050. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43264] EP260526a: COLIBRÍ optical upper limit
by GCN Circulars 27 Jun '26

27 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45049 SUBJECT: EP260526a: COLIBRÍ optical upper limit DATE: 26/06/27 10:31:22 GMT FROM: F. Magnani at Aix-Marseille Université, CPPM/CNRS <francesco.magnani.work(a)gmail.com> Francesco Magnani (CPPM), Fredd Sánchez Álvarez (UNAM), Jean-Grégoire Ducoin (CPPM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), and Alan M. Watson (UNAM) report: We imaged the field of the EP 260526a (J.P. Chen et al., GCN Circ. 45047) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-06-27T07:56:30 to 09:19:26 UTC (from 26.5 to 27.9 hours after the trigger) and obtained 64 minutes of simultaneous exposure in the r, z filters. The data were reduced, coadded, and analysed with the COLIBRÍ pipeline. The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. In the stacked image, we do not detect any new source at the WXT source position (J.P. Chen et al., GCN Circ. 45047) down to the following 3-sigma limit: r > 23.87 z > 23.15 This upper limit is consistent with the one reported by R. A. J. Eyles-Ferris et al., GCN Circ. 45048. We thank the staff of the Observatorio Astronómico Nacional at Sierra de San Pedro Mártir, as well as the technical and engineering teams at CEA, CPPM, IRAP, LAM, OHP, OSU Pytheas, and UNAM. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/45049. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43263] EP260626a: Liverpool Telescope upper limits
by GCN Circulars 27 Jun '26

27 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45048 SUBJECT: EP260626a: Liverpool Telescope upper limits DATE: 26/06/27 08:25:50 GMT FROM: Rob Eyles-Ferris at U of Leicester <raje1(a)leicester.ac.uk> R. A. J. Eyles-Ferris (Leicester), D. B. Malesani (DAWN/NBI and Radboud), J. Sanchez-Sierras (Radboud), G. Corcoran (UCD), A. Martin-Carrillo (UCD), P. G. Jonker (Radboud), report on behalf of a larger collaboration: We observed the field of the Einstein Probe fast X-ray transient EP260626a (Chen et al., GCN 45047) with the 2m Liverpool Telescope on La Palma using the IO:O instrument. We obtained 6x150 s exposures in each of the SDSS r’ and z’ filters starting at 2026-06-27 02:24:23 UT, approximately 21 hours after the X-ray detection. We performed image subtraction on the stacked images using reference images from Pan-STARRS and also compared the stacked and reference images manually. Within the EP/WXT localisation, we detect no new sources in any of the bands. We derive the following 3-sigma upper limits for our stacked images. Our photometry is calibrated to PanSTARRS and not corrected for Galactic extinction. | t_mid (hours) | Filter | AB magnitude | | ------------- | ------ | ------------ | | 21.13 | r’ | >22.89 | | 21.44 | z’ | >22.37 | View this GCN Circular online at https://gcn.nasa.gov/circulars/45048. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43262] EP260626a: EP-WXT detection of a fast X-ray transient
by GCN Circulars 26 Jun '26

26 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45047 SUBJECT: EP260626a: EP-WXT detection of a fast X-ray transient DATE: 26/06/26 15:13:06 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> J.P. Chen (SYSU), K. J. Zhang, D. Zhu (YNU), W. D. Zhang (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report on the detection of a fast X-ray transient, designated EP260626a, by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission. The transient was identified in the telemetry data. The transient was detected in the WXT observation starting at 2026-06-26T05:25:04 (UTC). A significant flare was detected in the source light curve, which started before the beginning of the observation and ended approximately 100 seconds after the start of the observation. The position of the transient is R.A. = 277.4417 deg, Dec. = 21.2403 deg (J2000), with an uncertainty radius of 2.7 arcmin in radius (90% confidence level, including both statistical and systematic uncertainties). There are no known X-ray sources in the WXT error circle. The average WXT 0.5-4 keV spectrum can be fitted by an absorbed power-law model with a fixed Galactic hydrogen column density of 2.04×10^21 cm^-2 and a photon index of 1.93 (-0.4/+0.42). The derived average unabsorbed 0.5-4 keV flux is 8.02 (-1.7/+2.1) x 10^(-11) erg cm^-2 s^-1. The uncertainties are at the 90% confidence level for the above parameters. Follow-up observations by EP-FXT will be arranged. Launched on 2024 January 9, Einstein Probe is a space-based X-ray observatory designed to monitor the dynamic X-ray sky and perform rapid follow-up observations of newly discovered transients (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45047. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43261] Konus-Wind detection of GRB 260623B / EP260623a
by GCN Circulars 26 Jun '26

26 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45046 SUBJECT: Konus-Wind detection of GRB 260623B / EP260623a DATE: 26/06/26 15:11:51 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> D. Svinkin, D. Frederiks, A.Lysenko, A. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 260623B was detected by Konus-Wind (KW) in the waiting mode at about T0 = T0(EP) = 10445 s UT (02:54:05). A Bayesian block analysis of the KW waiting mode data in the 20-300 keV band reveals a ~10 sigma count-rate increase in the interval from T0-259 s to T0+327 s. The burst overlaps in time with EP260623a (EP-WXT detection: Wang et al., GCN 45020; Wang et al., GCN 45035) and the KW ecliptic latitude response is consistent with the EP260623a localization. The positional and temporal coincidence of GRB 260623B with the EP260623a supports the conclusion that both events have a common origin. The KW light curve of this burst is available at http://www.ioffe.ru/LEA/GRBs/GRB260623B The total burst fluence is 8.2(-1.2,+1.2)x10^-6 erg/cm^2, and the 2.944 s peak energy flux, measured from T0+3.366 s, is 0.7(-0.3,+0.4)x10^-7 erg/cm^2/s. (both in the 20 keV - 1500 keV energy range). The time-integrated spectrum of the burst, measured from T0-258.650 s to T0+327.206 s, can be described by a power law with exponential cutoff (CPL) model dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha > -1.16 and Ep = 76(-8,+28) keV. The spectrum near the maximum count rate (measured from T0-2.522 to T0+38.694 s) can be described with the CPL model with alpha > -1.42 and Ep = 87(-15,+83) keV. Assuming the redshift z=0.703 (Izzo et al., GCN 45022) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is 1.13(-0.16,+0.24)x10^52 erg, the peak luminosity L_iso is 1.71(-0.72,+0.97)x10^50 erg/s, the rest-frame peak energy of the time-averaged spectrum Ep,i,z is 130(-14,+47) keV and the spectrum near the maximum count rate Ep,p,z is 148(-26,+143) keV. With the obtained estimates, GRB 260623B is inside the 68% prediction band for the 'Amati' and inside the 90% prediction band for the 'Yonetoku' relations derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB260623B/GRB260623B_rest_frame.pdf All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/45046. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43260] EP260623a: TNG NIR afterglow detection
by GCN Circulars 25 Jun '26

25 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45045 SUBJECT: EP260623a: TNG NIR afterglow detection DATE: 26/06/25 15:50:24 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio (INAF-OAB), M. Ferro (INAF-OAB), L. Izzo (INAF-OACN and DARK/NBI), D. B. Malesani (DAWN/NBI and Radboud), A. Melandri (INAF-OAR), V. Lorenzi (INAF-TNG), A. G. de Gurtubai Escudero (INAF-TNG) report on behalf of the CIBO collaboration: We observed the field of EP260623a detected by EP/WXT (Wang et al., GCN 45020) with the Italian 3.6m TNG telescope equipped with the near-infrared camera NICS to follow up its afterglow. A series of images were obtained with the K filter starting on 2026-06-25 at 01:29:13 UT (i.e. 1.94 days after the trigger). The afterglow (Li et al., GCN 45021; Izzo et al., GCN 45022; Angulo et al., GCN 45024; Brivio et al., GCN 45025; Jiang et al., GCN 45026; Li et al., GCN 45027; Jelinek et al., GCN 45029; Lee et al., GCN 45030; Saikia et al., GCN 45034; Bochenek & Perley, GCN 45040; Busmann et al., GCN 45042) is detected in the co-added image with a preliminary magnitude of K = 19.9 +/- 0.2 mag (Vega; calibrated against the 2MASS catalogue), at a mid-time of 1.96 days after the trigger. View this GCN Circular online at https://gcn.nasa.gov/circulars/45045. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43259] GRB 260618A: Fermi GBM Observation
by GCN Circulars 25 Jun '26

25 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45044 SUBJECT: GRB 260618A: Fermi GBM Observation DATE: 26/06/25 13:02:58 GMT FROM: Christian Malacaria at INAF-OAR <cmalacaria.astro(a)gmail.com> C. Malacaria (INAF-OAR) and R. Sonawane (IISER, TVM) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 06:45:34.28 UT on 18 June 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260618A (trigger 803457939/260618282). Final Real-time localization was reported in GCN 44973. A possible afterglow is detected by EP (Yang et al., GCN 44978, Jiang et al., GCN 44991). The GBM light curve consists of a variable emission episode with a duration (T90) of about 140 s (50-300 keV). The time-averaged spectrum from T0-17 to T0+150 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.4 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 43 +/- 2 keV. The event fluence (10-1000 keV) in this time interval is (5.9 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+25 s in the 10-1000 keV band is 2.7 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/45044. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43258] MASS-Cube (GRID 2.0) detection of GRB 260616B
by GCN Circulars 25 Jun '26

25 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45043 SUBJECT: MASS-Cube (GRID 2.0) detection of GRB 260616B DATE: 26/06/25 08:24:21 GMT FROM: GRID Student Team at Tsinghua University <grid(a)tsinghua.edu.cn> Jiahuan Zhu, Chenyu Wang, Xutao Zheng, Hao Chang, Zirui Yang report on behalf of the MASS-Cube Collaboration: MASS-Cube reports the detection of the long-duration GRB 260616B, which was also detected by Fermi/GBM (GCN #44953), EP (GCN #44956 and #44976), CALET (GCN #44966), SVOM (GCN #45011), HXMT (GCN #45023) and GRID-09. The event was triggered by MASS-Cube on 2026-06-16 at 07:05:14.5 UTC. The measured burst duration (T90) in the 50-10000 keV range is approximately 14.1 +/- 1.6 seconds. The MASS-Cube light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB260616B/MASS_Cub…. MASS-Cube is a pathfinder for a 3D position-sensitive Compton telescope in space, currently considered the next generation of the GRID constellation in the era of multi-messenger astronomy. For more information about MASS-Cube, please refer to the following reference: https://doi.org/10.1007/s10686-024-09920-4. View this GCN Circular online at https://gcn.nasa.gov/circulars/45043. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43257] EP260623a: FTW optical and NIR observations
by GCN Circulars 25 Jun '26

25 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45042 SUBJECT: EP260623a: FTW optical and NIR observations DATE: 26/06/25 08:19:33 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München <m.busmann(a)physik.lmu.de> Malte Busmann (LMU), Julius Gassert (LMU/CMU), Xander Hall (CMU), Brendan O'Connor (CMU), Daniel Gruen (LMU), and Antonella Palmese (CMU) report: We observed the counterpart of EP260623a (Wang et al., GCNs 45020 and 45035; Li et al., GCN 45021; Izzo et al., GCN 45022; Angulo et al., GCN 45024; Brivio et al., GCN 45025; Jiang et al., GCN 45026; Li et al., GCN 45027; Jelinek et al., GCN 45029; Lee et al., GCN 45030; Saikia et al., GCN 45034; Bochenek & Perley, GCN 45040) with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i and J band simultaneously for 20 x 180 s starting at 2026-06-24T23:13:34 UT (1.85 days after the trigger). We detect the counterpart in all bands and measure an r-band magnitude of r = 23.93 ± 0.22 AB mag. The magnitude is calibrated against the PS1 catalog and not corrected for Galactic extinction. We thank Christoph Ries from the Wendelstein Observatory for obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/45042. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43256] GRB 260619A: SVOM/ECLAIRs refined analysis
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45041 SUBJECT: GRB 260619A: SVOM/ECLAIRs refined analysis DATE: 26/06/24 20:31:19 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Nicolas Dagoneau (CEA), Marius Brunet (IRAP), Wenjin Xie (NAOC) Using the event-by-event data downloaded through the X-band ground station, we report further analysis of ECLAIRs observations of GRB 260619A (SVOM burst-id sb26061901). The burst that triggered ECLAIRs onboard (GCN 44985) consists of a faint single peak lightcurve with a duration of about 40 sec in the 8-50 keV energy band. The time-averaged spectrum (from T0-40.96 s to T0) in the energy range 5-120 keV is best fit by a blackbody model with a temperature kT = 6.6 -1.3/+1.6 keV. With this model, the 4-120 keV fluence is (2.03 +/- 0.63)*E-7 erg/cm² and the 4-120 keV photon flux is (2.02 +/- 0.33)*E-1 ph/cm²/s. All the quoted errors are at the 68% confidence level. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. The SVOM/ECLAIRs point of contact for this burst is: N. Dagoneau (nicolas.dagoneau at cea.fr) View this GCN Circular online at https://gcn.nasa.gov/circulars/45041. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43255] EP260623a: Liverpool Telescope optical observations
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45040 SUBJECT: EP260623a: Liverpool Telescope optical observations DATE: 26/06/24 17:59:07 GMT FROM: A. Bochenek at Liverpool John Moores University <a.m.bochenek(a)2023.ljmu.ac.uk> A. Bochenek, D. A. Perley (LJMU), report: We observed the field of EP260623a (Waang et al., GCN 45020; Wang et al., GCN 45035) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 6x120s exposures in SDSS griz filters, starting at 2026-06-24 01:15:57 UT, approximately 22.4 hours after EP trigger. Multiple exposures across all filters had to be discarded prior to stacking due to an issue with the telescope rotator. We detect a source in the images in all filters at the position reported by Li et al. (GCN 45021), also Izzo et al. (GCN 45022); Angulo et al. (GCN 45024); Brivio et al. (GCN 45025); Jiang et al. (GCN 45026); Li et al. (GCN 45027); Jelinek et al. (GCN 45029); Lee et al. (GCN 45030); Saikia et al. (GCN 45034). The preliminary photometry is: | MJD (mid) | T_mid-T_0 | Filter | Mag. (AB) | |---------------|-------------|-----------|---------------| | 61215.05694 | 22.49 h | g | > 21.44 | | 61215.06840 | 22.76 h | r | 21.96 ± 0.23 | | 61215.08921 | 23.26 h | i | 21.59 ± 0.13 | | 61215.09872 | 23.50 h | z | 21.06 ± 0.16 | The photometry is in the AB magnitude system, was calibrated using nearby PanSTARRS secondary standards and was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/45040. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43254] Fermi GBM trigger 804010507/260624677 is not a GRB
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45039 SUBJECT: Fermi GBM trigger 804010507/260624677 is not a GRB DATE: 26/06/24 17:44:48 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA) reports report on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 804010507/260624677 at 16:15:02.91 UT on 24 June 2026, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to particle activity." View this GCN Circular online at https://gcn.nasa.gov/circulars/45039. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43253] Konus-Wind detection of GRB 260618B
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45038 SUBJECT: Konus-Wind detection of GRB 260618B DATE: 26/06/24 17:14:43 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 260618B (Fermi-GBM detection: Fermi GBM team, GCN 44979; Veres & Meegan, GCN 45010; Fermi-LAT detection: Gupta et al., GCN 44983) triggered Konus-Wind at T0=60907.637 s UT (16:55:07.637). The burst light curve shows a multipeaked structure which starts at ~T0-1.6 s and has a total duration of ~61.2 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB260618_T60907/ As observed by Konus-Wind, the burst had the total fluence of 2.26(-0.34,+0.43)x10^-5 erg/cm2, and the 64-ms peak flux, measured from T0+0.378 s, of 4.90(-0.98,+1.01)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+57.600 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.83(-0.16,+0.19) and Ep = 1066(-241,+365) keV (chi2 = 94/98 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.7 (chi2 = 94/97 dof). The spectrum near the maximum count rate (measured from T0 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.39(-0.14,+0.15) and Ep = 817(-97,+119) keV (chi2 = 96/88 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -3.2 (chi2 = 96/87 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/45038. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43252] GRB 260624A: Fermi GBM Final Real-time Localization
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45037 SUBJECT: GRB 260624A: Fermi GBM Final Real-time Localization DATE: 26/06/24 16:09:12 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 15:54:14 UT on 24 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260624A (trigger 804009259.148196 / 260624663). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 54.1, Dec = -21.0 (J2000 degrees, equivalent to J2000 03h 36m, -21d 00'), with a statistical uncertainty of 4.4 degrees. The angle from the Fermi LAT boresight is 73.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260624663/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260624663/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260624663/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45037. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43251] GRB 260624A: Fermi GBM Final Real-time Localization
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45036 SUBJECT: GRB 260624A: Fermi GBM Final Real-time Localization DATE: 26/06/24 16:06:42 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 15:54:14 UT on 24 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260624A (trigger 804009259.148196 / 260624663). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 54.1, Dec = -21.0 (J2000 degrees, equivalent to J2000 03h 36m, -21d 00'), with a statistical uncertainty of 4.4 degrees. The angle from the Fermi LAT boresight is 73.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260624663/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260624663/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260624663/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45036. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43250] EP260623a:refined analysis of the EP-WXT and EP-FXT observation
by GCN Circulars 24 Jun '26

24 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45035 SUBJECT: EP260623a:refined analysis of the EP-WXT and EP-FXT observation DATE: 26/06/24 09:06:30 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> B.T. Wang (YNAO, CAS), Y. L. Hua (PMO, CAS) and C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: The fast X-ray transient EP260623a triggered the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission (Wang et al., GCN 45020) and followed by several optical telescopes (Li et al., GCN 45021; Angulo et al., GCN 45024; Brivio et al., GCN 45025; Jiang et al., GCN 45026; Li et al., GCN 45027; Jelinek et al., GCN 45029; Lee et al., GCN 45030; Saikia et al., GCN 45034) with the redshift confirmed at z=0.703 (Izzo et al., GCN 45022). The refined analysis of the WXT data shows that the event started at T0=2026-06-23T02:52:27Z (UTC) and lasted for 103 s before the observation was interrupted by the autonomous follow-up observation. The average WXT 0.5–4 keV spectrum can be fitted with an absorbed power-law model (tbabs*ztbabs*powerlaw) with a fixed Galactic hydrogen column density of 8.1 × 10^20 cm^-2 and a fixed redshift of z = 0.703. The best-fit photon index is 1.83 (-0.56/+0.63), and the intrinsic hydrogen column density is 2.25 (-0.97/+1.21) × 10^22 cm^-2. The derived average unabsorbed 0.5–4 keV flux is 3.17 (-0.74/+1.39) × 10^-9 erg/s/cm^2. The estimated peak flux is 1.0 × 10^-8 erg/s/cm^2, corresponding to a peak luminosity of 2.2 × 10^49 erg/s. The autonomous observation by the Follow-up X-ray Telescope (FXT) was performed at 2026-06-23T02:56:08 (UTC), about 3.7 minutes after T0. The exposure time of this observation is 3211 s. The on-ground analysis shows that an uncatalogued source was detected at R.A., Dec. = 328.2698, 12.7938 deg (J2000) with an uncertainty of about 10 arcsec (radius, 90% C.L. statistical and systematic). The FXT light curve displays two pulses structure lasting for around 210 s. The average FXT 0.5-10 keV spectrum can be fitted with an absorbed power law with a fixed Galactic equivalent hydrogen column density of 8.1 × 10^20 cm^-2 and a photon index of 1.96 (-/+ 0.03), and the intrinsic hydrogen column density is 0.94 (-/+ 0.04) × 10^22 cm^-2. The derived average unabsorbed 0.5-10 keV flux is 7.33 (-/+ 0.10) × 10^-9 erg/s/cm^2. The uncertainties are at the 90% confidence level for the above parameters. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/45035. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43249] EP260623a: WINTER J-band observations
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45034 SUBJECT: EP260623a: WINTER J-band observations DATE: 26/06/23 22:37:06 GMT FROM: Geoffrey Mo at Caltech / Carnegie Observatories <gmo(a)mit.edu> Aditya Pawan Saikia (IITB), Geoffrey Mo (Caltech/Carnegie), Tomas Ahumada (NOIRLab), Benjamin Schneider (LAM), Robert Stein (UMD), Viraj Karambelkar (Columbia), Danielle Frostig (CfA), Nathan Lourie (MIT), Robert Simcoe (MIT), and Mansi Kasliwal (Caltech) report: We observed the field of EP260623a (Wang et al., GCN 45020) in the near-infrared J band with the Palomar 1-m telescope, equipped with the 1.2-square degree WINTER camera (Lourie et al. 2020, Frostig et al. 2024). Observations began at 2026-06-23T07:00:29 UTC in the J band (4.1 hr after the EP trigger), consisting of 30*120 sec exposures. The images were processed using the WINTER data reduction pipeline implemented with MIRAR (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565) We detect a source at the optical counterpart location (Li et al., GCN 45021; Izzo et al., GCN 45022; Angulo et al., GCN 45024; Brivio et al., GCN 45025; Jiang et al., GCN 45026; Li et al., GCN 45027; Jelinek et al., GCN 45029; Lee et al., GCN 45030), with magnitude J = 17.9 ± 0.1 mag (AB). WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/45034. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43248] GRB 260617A: Glowbug gamma-ray detection of a short burst
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45033 SUBJECT: GRB 260617A: Glowbug gamma-ray detection of a short burst DATE: 26/06/23 22:12:11 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 260617A, which was also detected by Fermi/GBM (GCN 44969, 44972), Konus-Wind and Mars-Odyssey/HEND (GCN 44982, 44998), and CALET (GCN 44989). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2026-06-17 21:36:42.640 with a duration of 0.26 s and a total significance of about 27 sigma. The light curve comprises a multi-peaked emission similar to the CALET light curve (GCN 44989). The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/45033. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43247] IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45032 SUBJECT: IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube DATE: 26/06/23 19:49:02 GMT FROM: Yuhua Yao at IceCube/UW-Madison <yyao255(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-260622A (https:/.gov/circulars/45018) in a time range of 1000 seconds centered on the alert event time (2026-06-22 15:33:34.814 UTC to 2026-06-22 15:50:14.814 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-260622A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.4e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260622A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 3e+02 GeV and 2e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2026-06-21 15:41:54.814 UTC to 2026-06-23 15:41:54.814 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.6e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260622A in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/45032. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43246] IPN triangulation of GRB 260605A
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45031 SUBJECT: IPN triangulation of GRB 260605A DATE: 26/06/23 17:47:50 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, C. Wang (IHEP), S. Xiong (IHEP), S. Zhang (IHEP), J. Wei (NAOC), and B. Cordier (CEA) on behalf of the SVOM-GRM team, C. Wang (IHEP), S. Xiong (IHEP), and S. Zhang (IHEP) on behalf of the Insight-HXMT team, E. Burns on behalf of the IPN, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The long-duration GRB 260605A (Insight-HXMT/HE detection: Zao et al., GCN 44849) was detected by Insight (HXMT/HE), SVOM (GRM), Konus-Wind, and Mars-Odyssey (HEND) at about 3868 s UT (01:04:28). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: ------------------------------ RA(2000), deg Dec(2000), deg ------------------------------ Corners: 110.4929 +37.9757 110.4379 +38.1277 108.8194 +18.8592 108.8935 +19.0360 ------------------------------ The error box area is 3003 sq. arcmin, and its maximum dimension is 20.3 deg (the minimum one is 2.6 arcmin). The Sun distance was ~27 deg. This localization may be improved. A triangulation map and HEALPix FITS files are posted at http://www.ioffe.ru/LEA/GRBs/GRB260605_T03858/IPN The HEALPix triangulation map is the multi-order HEALPix in units of probability density. View this GCN Circular online at https://gcn.nasa.gov/circulars/45031. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43245] EP260623a: Optical follow-up observations with Kinder
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45030 SUBJECT: EP260623a: Optical follow-up observations with Kinder DATE: 26/06/23 16:42:04 GMT FROM: Amar Aryan at National Central University, Institute of Astronomy (NCUIA) <amararyan941(a)gmail.com> M.-H. Lee, A. Aryan, T.-W. Chen, W.-J. Hou (all NCU), A. K. H. Kong (NTHU), S. J. Smartt, J. Gillanders (both Oxford), S. Yang(HNAS), A. Sankar.K, K. N.-T. Ho, A. Dutta, Y.-H. Lee, Y.-C. Pan, C.-C. Ngeow, C.-H. Lai, H.-C. Lin, H.-Y. Hsiao, C.-S. Lin, J.-K. Guo (all NCU), Z. N. Wang, D. C. Qiang, L. L. Fan (all HNAS), Y. J. Yang (NYUAD), H.-W. Lin (UMich), K. W. Smith, H. F. Stevance, S. Srivastav, L. Rhodes (all Oxford), M. Nicholl, M. Fulton, C. Angus, A. Aamer (all QUB), T. Moore (STScI), A. Schultz and M. Huber (both IfA, Hawaii) report: We observed the field of the fast X-ray transient EP260623a (Wang et al., GCN 45020) using the 1m LOT at the Lulin observatory, as part of the Kinder collaboration (Chen et al. 2025, ApJ, 983, 86, doi:10.3847/1538-4357/adb428). The first LOT epoch of observations in r-band started at 15:26 UTC on the 23rd of June 2026 (MJD 61214.6431), 12.53 hr after the EP-WXT detection. We utilized the astroalign (Beroiz et al. 2020, A&C, 32, 100384) and astropy (Astropy Collaboration et al. 2022, ApJ, 935, 167) packages to align and stack the individual frames. Next, we employed the Python-based package AutoPhOT (Brennan & Fraser, 2022, A&A, 667, A62) to perform template subtraction with the DESI Legacy Survey (Dey et al. 2019, AJ 157, 168) DR10 image using the 'SFFT' (Hu et al. 2022, ApJ, 936, 157) algorithm. In the difference image, the optical counterpart (Li et al., GCN 45021; Izzo et al., GCN 45022; Angulo et al., GCN 45024; Brivio et al., GCN 45025; Jiang et al., GCN 45026; Li et al., GCN 45027; and Jelinek et al., GCN 45029) was clearly detected. Moreover, we further used AutoPhOT to perform PSF photometry. The details of the observations and measured photometry (in the AB system) are as follows: Telescope | Filter | MJD (start) | t-t0 (hr) | Exposure (s) | Magnitude | avg. Seeing | med. Airmass LOT | r | 61214.6431 | 12.53 | 300 * 6 | 20.74 +/- 0.07 | 1".97 | 1.91 The presented magnitudes are calibrated using the field stars from ATLAS-RefCat2 catalog from MAST (Tonry J. L. et al. 2018, ApJ, 867, 105). The reported magnitude is not corrected for an expected galactic extinction of A_r = 0.32 mag, in the direction of the transient (Schlafly & Finkbeiner 2011). The methodology, details on the Lulin observatory telescopes, and a compilation of our optical follow-up campaign for FXTs discovered within the first year of operation of the Einstein-Probe mission are presented in Aryan et al. 2025, ApJS, 281, 20, doi:10.3847/1538-4365/adfc69. View this GCN Circular online at https://gcn.nasa.gov/circulars/45030. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43244] EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45029 SUBJECT: EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay DATE: 26/06/23 14:29:58 GMT FROM: Martin Jelinek at Astro.Inst-AVCR,Ondrejov <martin.jelinek(a)asu.cas.cz> Martin Jelinek, Jan Strobl and Filip Novotny (ASU CAS Ondrejov, CZ), Sergey Karpov, Martin Masek, Petr Janecek, Jakub Jurysek, Jan Ebr, Ronan Cunniffe, Petr Travnicek and Michael Prouza (Institute of Physics, Prague, CZ) report: The 25cm robotic telescope FRAM-ORM at La Palma (Spain) reacted robotically to the alert of EP260623a (Wang et al. GCN 45020), obtaining a series of unfiltered images starting at 02:59:17 UT, i.e. ~5 min post trigger. The observation consists of a set of 20 x 20 s exposures followed by a longer set of 120 x 60 s exposures. We clearly detect the optical counterpart reported by other telescopes (Li et al. GCN 45021; Izzo et al. GCN 45022; Angulo et al. GCN 45024; Brivio et al. GCN 45025; Jiang et al. GCN 45026). The FRAM observations cover the rise of the transient, its peak and the subsequent decay. The source peaked at ~T0+24 min at a brightness of r ~ 15.4, after which it decays with a power-law index alpha ~ 1.7, with a few rebrightenings. The photometry is calibrated against the Atlas-REFCAT2 catalogue (Tonry et al. 2018, ApJ, 867, 105) and is not corrected for Galactic extinction. Extrapolating the observed decay to T0+24h yields a predicted brightness of r ~ 22.0. View this GCN Circular online at https://gcn.nasa.gov/circulars/45029. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43243] GRB 260623A: Fermi GBM Final Real-time Localization
by GCN Circulars 23 Jun '26

23 Jun '26

TITLE: GCN CIRCULAR NUMBER: 45028 SUBJECT: GRB 260623A: Fermi GBM Final Real-time Localization DATE: 26/06/23 13:09:24 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 12:56:49 UT on 23 Jun 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260623A (trigger 803912214.021094 / 260623539). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 39.3, Dec = -10.4 (J2000 degrees, equivalent to J2000 02h 37m, -10d 24'), with a statistical uncertainty of 11.8 degrees. The angle from the Fermi LAT boresight is 88.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260623539/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260623539/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260623539/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45028. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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