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[vsnet-grb-info 44022] EP261003a: COLIBRÍ optical upper limits
by GCN Circulars 03 Oct '26

03 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45801 SUBJECT: EP261003a: COLIBRÍ optical upper limits DATE: 26/10/03 05:04:14 GMT FROM: globus(a)astro.unam.mx Noémie Globus (UNAM), Jean-Grégoire Ducoin (CPPM), Camila Angulo (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), 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), Marion Guelfand (CPPM), Asuka Kuwata (UNAM), Massimiliano Lincetto (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Alan M. Watson (UNAM) report: We imaged the field of the EP261003a (Lao et al., GCN Circ. 45798) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-10-03 03:41:26 to 04:47:19 UTC (from 3.45 to 4.56 hours after the trigger) and obtained 51 minutes of simultaneous exposure in the r and z filters. The data were reduced and analyzed with the COLIBRÍ 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. In the stacked image, we do not detect any new source at the FXT source position down to the following 5-sigma limit: r > 23.88, z > 22.40. Further observations are ongoing. 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/45801. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44021] Trigger_21915: Swift ToO observations
by GCN Circulars 03 Oct '26

03 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45800 SUBJECT: Trigger_21915: Swift ToO observations DATE: 26/10/03 04:38:05 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a ToO observation of the Einstein Probe/WXT-detected event Trigger_21915. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/ToO_GRBs/00021915 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. These are not necessarily related to the Einstein Probe/WXT event. Any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/45800. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44020] Fermi GRB 261003A: Global MASTER-Net observations report
by GCN Circulars 03 Oct '26

03 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45799 SUBJECT: Fermi GRB 261003A: Global MASTER-Net observations report DATE: 26/10/03 02:45:49 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 (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (Lomonosov MSU) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) O.Gress, N.Budnev(ISU) M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) MASTER-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) started inspect of the Fermi GRB 261003A ( Fermi GBM team, GCN 45797) errorbox 4620 sec after notice time and 4654 sec after trigger time at 2026-10-03 02:36:10 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 80 deg. The sun altitude is -12.5 deg. The galactic latitude b = 4 deg., longitude l = 83 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3517714 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 4660 | 2026-10-03 02:36:10 | MASTER-Tavrida | (19h 21m 38.90s , +53d 18m 43.8s) | C | 10 | 15.7 | 4673 | 2026-10-03 02:36:22 | MASTER-Tavrida | (19h 21m 38.98s , +53d 18m 43.0s) | C | 10 | 15.7 | 4673 | 2026-10-03 02:36:23 | MASTER-Tavrida | (19h 21m 33.52s , +53d 20m 03.7s) | C | 10 | 14.2 | 4687 | 2026-10-03 02:36:36 | MASTER-Tavrida | (19h 21m 39.10s , +53d 18m 43.1s) | C | 10 | 15.8 | 4687 | 2026-10-03 02:36:36 | MASTER-Tavrida | (19h 21m 33.60s , +53d 20m 04.4s) | C | 10 | 14.1 | 4705 | 2026-10-03 02:36:50 | MASTER-Tavrida | (19h 21m 39.22s , +53d 18m 43.0s) | C | 20 | 16.2 | 4706 | 2026-10-03 02:36:50 | MASTER-Tavrida | (19h 21m 33.74s , +53d 20m 04.6s) | C | 20 | 14.6 | 4729 | 2026-10-03 02:37:13 | MASTER-Tavrida | (19h 21m 39.35s , +53d 18m 43.2s) | C | 20 | 16.0 | 4756 | 2026-10-03 02:37:36 | MASTER-Tavrida | (19h 21m 39.48s , +53d 18m 43.1s) | C | 30 | 16.2 | 4756 | 2026-10-03 02:37:36 | MASTER-Tavrida | (19h 21m 33.97s , +53d 20m 05.5s) | C | 30 | 14.6 | 4790 | 2026-10-03 02:38:10 | MASTER-Tavrida | (19h 21m 39.60s , +53d 18m 43.8s) | C | 30 | 16.3 | 4790 | 2026-10-03 02:38:10 | MASTER-Tavrida | (19h 21m 34.10s , +53d 20m 06.4s) | C | 30 | 14.6 | 4829 | 2026-10-03 02:38:43 | MASTER-Tavrida | (19h 21m 39.63s , +53d 18m 44.3s) | C | 40 | 16.4 | 4829 | 2026-10-03 02:38:44 | MASTER-Tavrida | (19h 21m 34.15s , +53d 20m 07.0s) | C | 40 | 14.9 | 4878 | 2026-10-03 02:39:27 | MASTER-Tavrida | (19h 21m 39.67s , +53d 18m 45.2s) | C | 50 | 16.5 | 4878 | 2026-10-03 02:39:27 | MASTER-Tavrida | (19h 21m 34.17s , +53d 20m 08.5s) | C | 50 | 14.9 | 4937 | 2026-10-03 02:40:21 | MASTER-Tavrida | (19h 21m 39.72s , +53d 18m 46.8s) | C | 60 | 16.5 | 4937 | 2026-10-03 02:40:21 | MASTER-Tavrida | (19h 21m 34.22s , +53d 20m 10.4s) | C | 60 | 14.9 | 5007 | 2026-10-03 02:41:27 | MASTER-Tavrida | (19h 21m 39.75s , +53d 18m 48.6s) | C | 70 | 16.5 | 5007 | 2026-10-03 02:41:27 | MASTER-Tavrida | (19h 21m 34.25s , +53d 20m 12.4s) | C | 70 | 14.9 | 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/45799. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44019] EP261003a: Einstein Probe detection of an X-ray transient
by GCN Circulars 03 Oct '26

03 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45798 SUBJECT: EP261003a: Einstein Probe detection of an X-ray transient DATE: 26/10/03 01:40:53 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Q.H. Lao, H.Y. Liu (NAO, CAS), Y.H. Jiang (NJU), Y.H. Cheng (YNU) and Y. Liu (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 EP261003a. The transient triggered EP-WXT (ID: 01709320865) at 2026-10-03T00:14:43 (UTC). The WXT position of the source is R.A. = 307.524 deg, DEC = -12.936 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. = 307.5318 deg, DEC = -12.9422 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/45798. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44018] GRB 261003A: Fermi GBM Final Real-time Localization
by GCN Circulars 03 Oct '26

03 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45797 SUBJECT: GRB 261003A: Fermi GBM Final Real-time Localization DATE: 26/10/03 01:29:04 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 01:18:35 UT on 3 Oct 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 261003A (trigger 812683120.140818 / 261003055). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 306.5, Dec = 45.7 (J2000 degrees, equivalent to J2000 20h 26m, 45d 42'), with a statistical uncertainty of 20.7 degrees. The angle from the Fermi LAT boresight is 87.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261003055/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261003055/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn261003055/… View this GCN Circular online at https://gcn.nasa.gov/circulars/45797. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44017] EP Alert 261003.01: Global MASTER-Net observations report
by GCN Circulars 03 Oct '26

03 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45796 SUBJECT: EP Alert 261003.01: Global MASTER-Net observations report DATE: 26/10/03 00:36:35 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> M. Segura, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA) 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 (Lomonosov MSU) D.Buckley (SAAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity) A.Sosnovskij (Lomonosov MSU) A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory) L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) R.Rebolo (The Instituto de Astrofisica de Canarias) O.Gress, N.Budnev(ISU) MASTER-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) was pointed to the EP Alert 261003.01 (trigger No 1709320865,20h 30m 05.76s , -12d 56m 09.6s, R=0.0510787) errorbox 20 sec after notice time and 366 sec after trigger time at 2026-10-03 00:20:50 UT, with upper limit up to 20.6 mag. The observations began at zenith distance = 19 deg. The sun altitude is -22.1 deg. The galactic latitude b = -28 deg., longitude l = 33 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3517655 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 402 | 2026-10-03 00:20:50 | MASTER-OAFA | (20h 28m 53.44s , -12d 56m 46.8s) | C | 70 | 19.9 | 502 | 2026-10-03 00:20:50 | MASTER-OAFA | (20h 28m 53.44s , -12d 56m 46.8s) | C | 270 | 20.6 | Coadd 487 | 2026-10-03 00:22:05 | MASTER-OAFA | (20h 28m 53.22s , -12d 56m 49.5s) | C | 90 | 20.1 | 594 | 2026-10-03 00:23:42 | MASTER-OAFA | (20h 28m 52.95s , -12d 56m 52.9s) | C | 110 | 20.1 | 720 | 2026-10-03 00:25:38 | MASTER-OAFA | (20h 28m 52.65s , -12d 56m 56.5s) | C | 130 | 20.1 | 871 | 2026-10-03 00:27:54 | MASTER-OAFA | (20h 28m 52.30s , -12d 57m 00.9s) | C | 160 | 20.2 | 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/45796. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44016] Fermi-LAT Gamma-ray Observations of IceCube-260930A
by GCN Circulars 02 Oct '26

02 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45795 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-260930A DATE: 26/10/02 20:23:19 GMT FROM: Leo Pfeiffer at University of Würzburg <pfeiffer.leo(a)gmail.com> L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg) and S. Garrappa (Weizmann Institute of Science) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC260930A neutrino event (GCN 45787) 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 2026-09-30 at 00:44:43.30 UTC (T0) with J2000 position RA = 235.59 (+0.49, -0.50) deg, Decl. = 0.97 (+0.56, -0.54) deg 90% PSF containment (J2000). No cataloged >100 MeV gamma-ray source is located within the 90% IC260930A localization error (FL16Y, The Fermi-LAT 16 Year Source List, The Fermi-LAT collaboration 2026, arXiv:2602.22148). 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 IC260930A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC260930A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 3.7e-10 ph cm^-2 s^-1 for ~18-years (2008-08-04 / T0), <2.8e-08 (<1.5e-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 analysis, the Fermi-LAT contact person is L. Pfeiffer (leonard.pfeiffer at uni-wuerzburg.de). 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/45795. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44015] Fermi GBM Detection of GRB 260919A / EP260920a
by GCN Circulars 01 Oct '26

01 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45794 SUBJECT: Fermi GBM Detection of GRB 260919A / EP260920a DATE: 26/10/01 21:27:44 GMT FROM: rhamburg(a)usra.edu R. Hamburg (USRA), A. Trigg (NASA/MSFC), O. Mukherjee (USRA), and E. Burns (LSU) report on behalf of the Fermi-GBM Team: The Einstein Probe WXT detected the fast X-ray transient EP260920a on 2026-09-20T00:06:04 UTC (GCN 45649). The Fermi Gamma-ray Burst Monitor (GBM) Targeted Search [1], the most sensitive coherent search for GRB-like signals in GBM, identified GRB 260919A, a bright and spatially-consistent transient with a duration of roughly 250 s. This GRB was detected most significantly at 2026-09-19T23:52:04.224 UTC, and was found on the 8.192 s timescale using a normal GRB spectrum (Band function with Epeak = 230 keV, alpha = -1.0, beta = -2.3). The Targeted Search significance of GRB 260919A is well within the range of on-board triggers, but GRB 260919A occurred within the 10 min post-trigger interval after GBM trigger 260919992 / 811554497 during which further GBM triggering is disabled. GBM trigger 260919992 / 811554497 was detected at 2026-09-19T23:48:12.80, approximately 800 s before the EP trigger time, and was initially classified as a TGF by the flight software. It was subsequently classified as uncertain due to extreme localization uncertainties. The connection between GBM trigger 260919992 / 811554497 and GRB 260919A is currently uncertain. Combining the Targeted Search localization with the IPN localization (GCN 45792), we find the spatial association probability between GRB 260919A and EP260920a is 99% (0.9887). We note the large temporal offset of approximately 600 s. However, the spatial coincidence suggests a common origin between GRB 260919A and EP260920a. [1] Goldstein et al. 2019 arXiv:1903.12597 View this GCN Circular online at https://gcn.nasa.gov/circulars/45794. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44014] IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 01 Oct '26

01 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45793 SUBJECT: IceCube-260930A: Upper limits from a search for additional neutrino events in IceCube DATE: 26/10/01 19:29:55 GMT FROM: syan079(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-260930A (https://gcn.nasa.gov/circulars/45787) in a time range of 1000 seconds centered on the alert event time (2026-09-30 00:36:23.390 UTC to 2026-09-30 00:53:03.390 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-260930A. 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, ranges from 1.4e-01 to 1.5e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-260930A 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 (2026-09-29 00:44:43.390 UTC to 2026-10-01 00:44:43.390 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-260930A 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/45793. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 44013] IPN triangulation of GRB 260919A / EP260920a
by GCN Circulars 01 Oct '26

01 Oct '26

TITLE: GCN CIRCULAR NUMBER: 45792 SUBJECT: IPN triangulation of GRB 260919A / EP260920a DATE: 26/10/01 13:14:13 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> D. Svinkin, D. Frederiks, A. Lysenko, V. Panteleeva, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi-GBM team, report: The long-duration GRB 260919A was detected by Konus-Wind and Fermi (GBM trigger 811554497) at about 85692 s UT (23:48:12). We have triangulated it to the 3 sigma IPN localization region whose area is 6556 sq. deg, and its maximum dimension is 147 deg (the minimum one is ~66 deg). This localization may be improved. The fast X-ray transient EP260920a (Ni et al., GCN 45649) which was detected ~800 s after GRB 260919A, is inside the IPN localization region. The positional and temporal proximity of GRB 260919A with EP260920a may suggest that both events have a common origin. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB260919_T85725/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/45792. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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