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

[vsnet-grb-info 43090] GRB 260614A: Fermi GBM Final Localization
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44935 SUBJECT: GRB 260614A: Fermi GBM Final Localization DATE: 26/06/14 11:49:11 GMT FROM: Rushikesh Sonawane at IISER TVM <rushikesh23(a)iisertvm.ac.in> The Fermi GBM team reports the detection of a likely LONG GRB "At 10:06:14.62 UT on 14 June 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260614A (trigger 803124379/260614421). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 192.76, Dec = -38.51 (J2000 degrees, equivalent to J2000 12h 51m, -38d 30'), with a statistical uncertainty of 6.04 degrees. The angle from the Fermi LAT boresight is 106 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260614421/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260614421/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260614421/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/44935. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43089] The EP-WXT trigger 01709269488 is likely a flaring star
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44934 SUBJECT: The EP-WXT trigger 01709269488 is likely a flaring star DATE: 26/06/14 06:18:14 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin (HKU), G. Y. Zhao (SYSU), Z. M. Wang (BNU) and W. D. Zhang (NAO,CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709269488 at the time of 2026-06-14T05:58:28, is likely a stellar flare associated with Wolf 1473 (Spectroscopic Binary). The estimated flux of the flare is around 1 x 10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 2 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/44934. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43088] GRB 260603C: AstroSat CZTI detection
by GCN Circulars 14 Jun '26

14 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44933 SUBJECT: GRB 260603C: AstroSat CZTI detection DATE: 26/06/14 00:21:34 GMT FROM: Gaurav Waratkar at Caltech <gauravwaratkar(a)iitb.ac.in> S.Salunke (IUCAA), Harsha K. H. (IUCAA), A. Goyal (IITB), A. Arya (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 long-duration GRB 260603C. The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2026-06-03 20:22:40.3. The measured peak count rate associated with the burst is 83 (+25, -18) counts/s above the background in the combined data of two quadrants (out of four), with a total of 1141 (+467, -343) counts. The local mean background count rate was 150 (+0.7, -2) counts/s. We measure a T90 of 71 (+25, -13) s from the cumulative CZT light curve. The source was faintly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve, with a single burst of emission, peaks at 2026-06-03 20:22:40.2. The measured peak count rate associated with the burst is 250 (+71, -36) counts/s above the background in the combined data of all quadrants, with a total of 822 (+283, -302) counts. The local mean background count rate was 1204 (+8, -8) counts/s. We measure a T90 of 5 (+4, -2) s from the cumulative Veto light curve, much lower than the T90 estimated in CZT detectors. We attribute this to a likely unfavorable angle from the boresight for Veto detectors. CZTI data products like interactive and downloadable light curves for this GRB can be found at: http://astrosat.iucaa.in/cift/cift_products/518214162.17/S518214162.17_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/44933. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43087] GRB 260610B: further Liverpool Telescope optical observations
by GCN Circulars 13 Jun '26

13 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44932 SUBJECT: GRB 260610B: further Liverpool Telescope optical observations DATE: 26/06/13 19:36:46 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 the optical counterpart (O'Neil et al., GCN 44903) of GRB 260610b (Fu et al., GCN 44901) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 5x120s exposures in SDSS griz filters, starting at 2026-06-13 01:22:29 UT, approximately 2.07 days after Fermi trigger. Some exposures had to be discarded prior to stacking. We detect a source in the images in all filters at the position reported by O'Neil et al. (GCN 44903), observed also by Watson et al. (GCN 44905); Zhu et al. (GCN 44909); Gillanders et al. (GCN 44910); Akl et al. (GCN 44911); O'Neill et al. (GCN 44914); Moskvitin et al. (GCN 44918); Jackson-Horne et al. (GCN 44919); Izzo, (GCN 44920), Li et al. (GCN 44921), Bochenek et al. (GCN 44927), Moskvitin et al. (GCN 44929); and Akl et al. (GCN 44930) . The photometry is: | MJD (mid) | T_mid-T_0 | Filter | Mag. (AB) | |---------------|-------------|-----------|---------------| | 61204.05962 | 49.66 h | r | 21.05 ± 0.07 | | 61204.07237 | 49.97 h | i | 20.61 ± 0.09 | | 61204.07751 | 50.08 h | z | 20.28 ± 0.12 | | 61204.08753 | 50.33 h | g | 21.40 ± 0.14 | The photometry was calibrated using nearby PanSTARRS secondary standards and was not corrected for extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44932. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43086] GRB 260610B: Fermi GBM Observation
by GCN Circulars 13 Jun '26

13 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44931 SUBJECT: GRB 260610B: Fermi GBM Observation DATE: 26/06/13 18:21:44 GMT FROM: Matt Godwin <msg0028(a)uah.edu> Matt Godwin (UAH) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 23:46:14.25 UT on 10 June 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260610B (trigger 802827979/260610990). An optical counterpart is identified by GOTO (O'Neill, et al. 2026, GCN 44903). The redshift of the source is measured to be z = 0.473, ALFOSC/NOT (ONeill et al. 2026, GCN 44914). The Fermi GBM on-ground location is consistent with the GOTO position. The angle from the Fermi LAT boresight is 97 degrees. The GBM light curve consists of three peaks with a duration (T90) of about 62 s (50-300 keV). The time-averaged spectrum from T0-2.4 to T0+55.4 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.50 +/- 0.01 and the cutoff energy, parameterized as Epeak, is 46.8 +/- 0.4 keV. The event fluence (10-1000 keV) in this time interval is (1.30 +/- 0.02)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.8 s in the 10-1000 keV band is 7.7 +/- 0.3 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak= 45.9 +/- 0.5 keV, alpha = -1.4800 +/- 0.0009 and beta = -3.17 +/- 0.01. 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/44931. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43085] GRB 260610B / AT2026owq: GRANDMA optical observations
by GCN Circulars 13 Jun '26

13 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44930 SUBJECT: GRB 260610B / AT2026owq: GRANDMA optical observations DATE: 26/06/13 13:50:34 GMT FROM: Dalya Akl at New York University Abu Dhabi <dka2010(a)nyu.edu> D. Akl (NYUAD), M. Mašek (FZU), R. Hanna (IJCLAB), P. Putsathan (KKU), Y. Rajabov (UBAI), S. Antier (IJCLAB), P. Hello (IJCLAB), M. Coughlin (UNM), S. Karpov (FZU), M. Pillas (IAP), C. Douzet (IJCLAB), A. Simon (TShNU of Kyiv), D. Rusanova (TShNU of Kyiv), V. Vasylenko (NC JASU), O. Burkhonov (UBAI), S. Ehgamberdiev (UBAI), Y. Tillayev (UBAI), P. Put (NARIT), K. Noysena (NARIT), M. Tanasan (CMU/NARIT), D. Turpin (CEA-Saclay/Irfu), M. Freeberg (KNC), A. Klotz (IRAP), C. Limonta (OCA), A. Dupin (OCA), Q. André (OCA), M. Molham (NRIAG), E. Elhosseiny (NRIAG), A. Takey (NRIAG), N. Kochiashvili (AbAO), R. Inasaridze (AbAO), V. Zhuzhunadze (AbAO) on behalf of the GRANDMA collaboration: We observed the field of the Fermi Long GRB 260610B (Fermi GBM team, GCN 44901). The observations started at 16:29:50 UTC on the 11 of June 2026, 0.7 days post the Fermi Trigger. We detected the optical afterglow candidate, reported by GOTO (O'Neill et al, GCN 44903), in several epochs, using TRT-SRO in California state, UBAI-NT60, UBAI-AZT-22 at Madainak Observatory, AZT-8 at Lisnyky Observatory, KAO-1.88m at Kottamia Astronomical Observatory, TAROT-TCA/TCH at Calern and La Silla, and Kilonova Catcher. A subset of the photometry corrected for Galactic extinction is reported in the public ACME service Skyportal/ICARE https://skyportal-icare.ijclab.in2p3.fr/source/2026owq. To access, one simply needs to create an account using your ORCID ID. 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. The results are consistent with other measurements reported (Zhu et al., GCN 44909; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Li et al., GCN 44921; Bochenek and Perley, GCN 44927; Moskvitin et al., GCN 44929) 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/44930. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43084] GRB 260610B / AT2026owq: further SAO RAS optical observations
by GCN Circulars 13 Jun '26

13 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44929 SUBJECT: GRB 260610B / AT2026owq: further SAO RAS optical observations DATE: 26/06/13 06:35:11 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin (SAO RAS), O. Spiridonova (SAO RAS), A. Pozanenko (IKI), A. Volnova (IKI), N. Pankov (IKI) report on behalf of GRB follow-up team We observed the field of GRB 260610B discovered by Fermi (The Fermi GBM team, GCN 44891; GCN 44901) with the Zeiss-1000 1-m telescope of SAO RAS + CCD photometer in BVRcIc filters on June 12. The OT (O'Neill et al., GCN 44903; Watson et al., GCN 44905; Zhu et al., GCN 44909; Gillanders et al., GCN 44910; Akl et al., GCN 44911; O'Neill et al., GCN 44914; Moskvitin et al., GCN 44918; Jackson-Horne et al., GCN 44919; Izzo, GCN 44920; Li et al., GCN 44921; Bochenek and Perley, GCN 44927) is clearly detected in our frames with the following brightness: Date, UTstart, t-T0, Exp., Filter, Mag, Err., UL (mid,d) (n*s) (3-sigma) 2026-06-12 19:21:03 2.41821 5*300 Rc 20.61 0.03 23.5 This preliminary photometry is based on nearby SDSS stars (using Lupton 2005 transformation equations) and not corrected for Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/44929. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43083] EP260605a: COLIBRÍ optical upper limits
by GCN Circulars 12 Jun '26

12 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44928 SUBJECT: EP260605a: COLIBRÍ optical upper limits DATE: 26/06/12 19:15:05 GMT FROM: Rosa Leticia Becerra Godínez at Instituto de Astronomía, UNAM <rbecerra(a)astro.unam.mx> Rosa L. Becerra (UNAM), Massimiliano Lincetto (CPPM), Asuka Kuwata (UNAM), Sarah Antier (IJCLAB), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (NYUAD), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Marion Guelfand (CPPM), Nikos Mandarakas (LAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), and Alan M. Watson (UNAM) report: We imaged the field of the EP260605a (Li et al., GCN Circ. 44847) using the DDRAGO two-channel wide-field imager on the COLIBRÍ telescope. We observed from 2026-06-06 07:27 to 08:05 UTC (from 21.93 to 22.59 hours after the trigger) and obtained 29 minutes of simultaneous exposure in the r and z filters. Given the proximity of the localization region to the Galactic bulge, we obtained additional observations to serve as templates. The field was reimaged on 2026-06-12 from 07:06 to 08:06 UTC (from 6.90 to 6.94 days after the trigger), yielding 42 minutes of simultaneous exposure in the r and z filters. The data were reduced and coadded with the COLIBRÍ pipeline and analysed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the SkyMapper catalog, is in the AB system, and is not corrected for Galactic extinction. In the image subtraction, we do not detect any new source within the FXT error region (Li et al., GCN Circ. 44867) down to the following 5-sigma limit: r > 21.4 z > 20.6 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/44928. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43082] GRB 260610b: Liverpool Telescope optical observations
by GCN Circulars 12 Jun '26

12 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44927 SUBJECT: GRB 260610b: Liverpool Telescope optical observations DATE: 26/06/12 18:02:21 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 the optical counterpart (O'Neil et al., GCN 44903) of GRB 260610b (Fu et al., GCN 44901) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 5x120s exposures in SDSS griz filters, starting at 2026-06-10 23:39:02 UT, approximately 23.9 hours after trigger. We detect a source in the stacked images in all filters at the position reported by O'Neil et al. (GCN 44903), observed also by Watson et al. (GCN 44905); Zhu et al. (GCN 44909); Gillanders et al. (GCN 44910); Akl et al. (GCN 44911); O'Neill et al. (GCN 44914); Moskvitin et al. (GCN 44918); Jackson-Horne et al. (GCN 44919); Izzo, (GCN 44920), and Li et al. (GCN 44921). The photometry is: | MJD (mid) | T_mid-T_0 | Filter | Mag. (AB) | | ------------ | ------------ | ------------ | ------------ | | 61202.98947 | 23.98 h | r | 20.22 ± 0.02 | | 61202.99795 | 24.18 h | i | 19.89 ± 0.02 | | 61203.00646 | 24.38 h | z | 19.78 ± 0.05 | | 61203.01493 | 24.59 h | g | 20.66 ± 0.03 | 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/44927. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 43081] EP260610b: Liverpool Telescope optical upper limits
by GCN Circulars 12 Jun '26

12 Jun '26

TITLE: GCN CIRCULAR NUMBER: 44926 SUBJECT: EP260610b: Liverpool Telescope optical upper limits DATE: 26/06/12 17:56:45 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 EP260610b (Wu et al., GCN 44895, Guo et al., GCN 44912) using the IO:O optical camera on the 2m robotic Liverpool Telescope. We obtained 8x200s exposures in SDSS gri filters, starting at 2026-06-11 00:29:50.385 UT, approximately 1.46 days after trigger. We do not detect any sources at the position of the counterpart in the stacked images (Levan et al., GCN 44897; Xin et al., GCN 44900; Zhu et al., GCN 44902; Burkhonov et al., GCN 44904; Moreno Mendez et al., GCN 44906, van Hoof et al., GCN 44915) down to the three-sigma limiting magnitude of g > 23.2, r > 23.5, i > 22.9. We note that forced PSF photometry on r-band exposures gives a two-sigma detection at 23.7 ± 0.5 mag, at a mid-observation time of 1.52 days post-trigger. 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/44926. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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