February 2026 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41719] EP260110a: Late GTC/EMIR near-infrared observations
by GCN Circulars 04 Feb '26

04 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43615 SUBJECT: EP260110a: Late GTC/EMIR near-infrared observations DATE: 26/02/04 20:43:55 GMT FROM: javisansie(a)gmail.com J. Sanchez-Sierras (Radboud), A. van Hoof (Radboud), P. G. Jonker (Radboud), D. Mata-Sanchez (IAC and ULL), A. J. Levan (Radboud), D. B. Malesani (DAWN/NBI and Radboud Univ.) report on behalf of a larger collaboration: We observed the field of fast X-ray transient EP260110a (Zhang et al., GCNs 43363, 43367) with the Espectrógrafo Multiobjeto Infra-Rojo (EMIR) attached to the Gran Telescopio Canarias (GTC). The observations were performed in imaging mode and consisted of 260x5 s exposures, with a total exposure time of 1280 s in the H band, starting on 2026-02-01 at 06:08:10 UT (i.e. 21.76 days after the EP-WXT trigger). We used this observation as a template to perform image subtraction from the GTC/EMIR image reported by Corcoran et al. (observed 19.02 hr after the trigger; GCN 43391), which had the same exposure time and instrument configuration. The subtraction was made using the ZOGY algorithm (Zackay et al. 2016), as implemented in PyZOGY (Guevel et al. 2021). No new sources are detected inside the EP-FXT error circle in the subtraction, down to the limit of the least deep image, i.e. upper limiting AB magnitude of H > 23.3 (calibrated using nearby stars from the 2MASS catalog). View this GCN Circular online at https://gcn.nasa.gov/circulars/43615. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41718] GRB 260204B: Fermi GBM Final Real-time Localization
by GCN Circulars 04 Feb '26

04 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43614 SUBJECT: GRB 260204B: Fermi GBM Final Real-time Localization DATE: 26/02/04 17:00:30 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 LONG GRB At 16:50:06 UT on 4 Feb 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260204B (trigger 791916611.958652 / 260204701). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 338.5, Dec = -50.1 (J2000 degrees, equivalent to J2000 22h 33m, -50d 06'), with a statistical uncertainty of 6.4 degrees. The angle from the Fermi LAT boresight is 70.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260204701/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260204701/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260204701/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43614. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41717] GRB 260204A: SVOM detection of a burst
by GCN Circulars 04 Feb '26

04 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43613 SUBJECT: GRB 260204A: SVOM detection of a burst DATE: 26/02/04 15:09:47 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Pillas (IAP), M. Dennefeld (IAP), M. Brunet (IRAP), S. Guillot (IRAP), C. Pellouin (IAP), report on behalf of the SVOM mission team: At 2026-02-04T14:48:49 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 260204A (SVOM burst-id sb26020403). 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 6 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 10.87 in the [5-20] keV energy band over a time window of 40.96 seconds starting at 2026-02-04T14:48:28. The localization of the best alert is R.A., Dec. 205.1185, 2.0200 degrees: R.A. (J2000) = 13h40m28.44s Dec. (J2000) = 2d01m12.14s with a 90% confidence level (C.L.) radius of 7.36 arcmin (including systematic error of 2 arcmin added in quadrature). SVOM slewed to the burst. No X-ray observation could be performed by SVOM/MXT for the time being, due to Earth occultation. SVOM/VT observations will be reported in future circular. 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 Marion Pillas: marion.pillas(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/43613. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41716] GCN Announcement: New CHIME, DSA-110 and IceCube Notices, and Schema v6.1.1
by GCN Announcements 04 Feb '26

04 Feb '26

CHIME Fast Radio Burst Notices The CHIME Team and the GCN Team are pleased to announce the availability of a new CHIME Fast Radio Burst (FRB) notice type via the new GCN in JSON format. We welcome this new transient type to the GCN community and encourage follow-up observations. These notices can be streamed via Kafka. They are not available via GCN Classic. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a transit radio telescope located in Penticton, BC, Canada. It consists of 4 semi-cylindrical reflectors, each with 2000 square meters of collecting area and 256 dual-polarization antennas. The telescope observes between 400 MHz and 800 MHz and covers an instantaneous field of view of ~200 square degrees. CHIME houses several electronic backends, which are tailored for specific scientific goals, such as generating cosmological maps of hydrogen density, detecting Fast Radio Bursts, and observing and timing pulsars. In particular, the FRB backend operates at ~1 ms time resolution and ~ 0.4 MHz frequency resolution. The new CHIME notices provide FRB detection details including ~arcminute localization with a latency of ~1 minute. The detection rate is ~600 per year. Notices will be distributed on the Kafka topic: gcn.notices.chime.frb A more extensive description of the information provided in these new notices is available at https://gcn.nasa.gov/missions/chime. ______________________________________ DSA-110 Fast Radio Burst Notices The DSA-110 Team and the GCN Team are pleased to announce the availability of DSA-110 notice types via the new GCN in JSON format. These notices can be streamed via Kafka. The Deep Synoptic Array-110 (DSA-110) is a radio interferometer purpose-built for fast radio burst (FRB) detection and direct localization. The array is located at the Owens Valley Radio Observatory (OVRO) comprised of 96 4.65-m dishes that continuously survey for FRBs at frequencies between 1280 to 1530 MHz. Over a three-year science program, the DSA-110 will deliver a sample of more than 300 FRBs, each localized to regions ~1 arcminute radius within 1 minute of detection. This is made possible by a suite of novel instrumentation, including precisely engineered antennas, ultra-low noise ambient-temperature receivers, and a powerful real-time, autonomous data-analysis system. DSA-110 notices provide FRB detection and localization distributed on the Kafka topic: gcn.notices.dsa110.frb See the DSA-110 mission page (https://gcn.nasa.gov/missions/dsa_110) for a more extensive description of the information provided in these new notices. ______________________________________ IceCube Gold/Bronze Track Alert Notices The IceCube Team and the GCN Team are pleased to announce the availability of a new IceCube Notice type via the new GCN in JSON format for Gold/Bronze Track alerts. These notices can be streamed via Kafka. The information included in the JSON-format Notices largely overlaps with that in GCN Classic with the addition of a URL for multi-order probability maps. AMON_ICECUBE_GOLD and AMON_ICECUBE_BRONZE notices remain available via GCN Classic and GCN Classic over Kafka. IceCube is a cubic-kilometer Cherenkov particle detector deployed in the Antarctic ice beneath the Amundsen-Scott South Pole Station. IceCube detects neutrinos by observing the light produced by relativistic charged particles created by neutrino interactions in or near the instrumented volume of ice. The new Gold/Bronze Notices provide high-energy (TeV-PeV) track-like alerts with radius angular resolution. Events are classified into Gold and Bronze based on their likelihood of being astrophysical. Two GCN Notices are sent for each event - one corresponding to the preliminary reconstruction and one corresponding to the revised reconstruction. Gold and Bronze events occur at a rate of 10 and 16 per year, respectively, with a latency of 0.5-1 minute from detection. These new alerts are distributed via GCN Kafka on the topic: gcn.notices.icecube.gold_bronze_track_alerts The IceCube documentation (https://gcn.nasa.gov/missions/icecube) has been extensively updated. It now includes details on the new information released with the updated schema, as well as explanations of the quantities listed in the FITS file headers for the multi-order probability maps. ______________________________________ Schema v6.1.1 GCN Schema v6.1.1 is available with recent changes including new Notice types (Release Notes; https://github.com/nasa-gcn/gcn-schema/releases/tag/v6.1.1) For more details on this new feature and an archive of GCN news and announcements, see https://gcn.nasa.gov/news. For questions, issues, or bug reports, please contact us via: - Contact form: https://gcn.nasa.gov/contact - GitHub issue tracker: https://github.com/nasa-gcn/gcn.nasa.gov/issues --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41715] GRB 260121A: 239Alferov CubeSat detection
by GCN Circulars 03 Feb '26

03 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43612 SUBJECT: GRB 260121A: 239Alferov CubeSat detection DATE: 26/02/03 16:12:40 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> D. Svinkin (Ioffe), D. Frederiks (Ioffe), D. Kapshtan (Geoscan), M. Orlov (Geoscan), V. Bazunova (Geoscan), E. Shchepin (Geoscan), E. Meltsov (Geoscan), K. Starikov (Geoscan, SPbSU), A. Khogoev (Geoscan), A. Razdobarin (SPbAU), and D. Dolmatov (SPbSU), on behalf of the 239Alferov team, report: The long-duration GRB 260121A (IPN triangulation: Kozyrev et al., GCN 43564; Konus-Wind detection: Ridnaia et al., GCN 43611) was detected by 239Alferov 3U CubeSat at about 8552 s (02:22:32) UT. The burst light curve, as measured by 239Alferov detector, shows a single pulse with a duration of ~13 s. The emission is seen up to above ~1 MeV. The light curve recorded by 239Alferov is available at: http://www.ioffe.ru/LEA/GRBs/GRB260121_T08549/239Alferov/ 239Alferov is an educational 3U CubeSat mission at SSO combining amateur radio and space research objectives. The gamma-ray detector onboard 239Alferov contains a 64x72x15 mm NaI(Tl) scintillator read out by a SiPM array and covers the energy range from ~20 keV to ~1000 keV. The spacecraft is now at a commissioning stage, with scientific observations started in December 2025. Currently, the instrument records count rates in five energy bands: ~20-50 keV, ~50-100 keV, ~100-500 keV, 500-1000 keV, and > 1000 keV, with 1 s temporal resolution. The surveys span a couple of days with about a day-long analysis and maintenance intervals between the observations. The ground segment of the mission utilizes the SONIKS open ground station network. View this GCN Circular online at https://gcn.nasa.gov/circulars/43612. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41714] Konus-Wind detection of GRB 260121A
by GCN Circulars 03 Feb '26

03 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43611 SUBJECT: Konus-Wind detection of GRB 260121A DATE: 26/02/03 14:59:17 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 260121A (IPN triangulation: Kozyrev et al., GCN 43564) triggered Konus-Wind at T0=8549.319 s UT (02:22:29.319). The burst light curve shows a single pulse which starts at ~T0-0.5 s and has a total duration of ~21.6 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/GRB260121_T08549/ As observed by Konus-Wind, the burst had a fluence of 2.79(-0.46,+0.47)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.512 s, of 2.09(-0.31,+0.32)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+10.240 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.82(-0.11,+0.13), the high energy photon index beta = -2.07(-0.33,+0.18), the peak energy Ep = 366(-60,+75) keV (chi2 = 97/97 dof). The spectrum near the maximum count rate (measured from T0+0.256 to T0+2.304 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.75(-0.12,+0.15), the high energy photon index beta = -1.78(-0.11,+0.09), the peak energy Ep = 367(-73,+90) keV (chi2 = 123/97 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/43611. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41713] GRB 260131A/B: OHP/T193 optical observations
by GCN Circulars 03 Feb '26

03 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43610 SUBJECT: GRB 260131A/B: OHP/T193 optical observations DATE: 26/02/03 14:29:32 GMT FROM: Christophe Adami at LAM <christophe.adami(a)lam.fr> C. Adami (LAM/Pytheas/AMU), S. Basa (UAR Pytheas), N. Globus (UNAM), A. Watson (UNAM), B. Schneider (LAM), E. Le Floc'h (CEA-Saclay) report on behalf of the MISTRAL GRB collaboration: We carried out observations of GRB 260131A/B (Fermi GBM Team, GCN 43579; Sugai et al., GCN 43580; Roberts et al., GCN 43585; Frederiks et al., GCN 43590; Luo et al., GCN 43591; Jiang et al., GCN 43600; Li et al., GCN 43605) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. We obtained 7 exposures for a total of 14 min in the r-band at a midtime of 2026-02-01 19:48UT, corresponding to T-T0 = 37.15 hours. The afterglow reported by Gompertz et al., GCN 43586; Lee et al., GCN 43587; Saccardi et al., GCN 43595; García García et al., GCN 43599, Shi et al., GCN 43601; Sanchez-Ramirez et al., GCN 43604; Jayaraman et al., GCN 43606; Zhu et al., GCN 43607 ; Zheng et al., GCN 43609 is well detected in r’ with a preliminary magnitude of : r’ = 19.09 +/- 0.08 The photometric calibration was performed using nearby stars from the PanSTARRS catalog, is in the AB system, and is not corrected for Galactic extinction. We acknowledge the excellent support from the Observatoire de Haute-Provence and in particular Jean Balcaen and Stephane Favard, and the SOPHIE observer Xavier Delfosse. View this GCN Circular online at https://gcn.nasa.gov/circulars/43610. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41712] GRB 260131A: KAIT optical observations
by GCN Circulars 03 Feb '26

03 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43609 SUBJECT: GRB 260131A: KAIT optical observations DATE: 26/02/03 07:55:33 GMT FROM: Weikang Zheng at UC Berkeley <weikang(a)berkeley.edu> WeiKang Zheng (UCB) 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, observed the field of GRB 260131A (Fermi GBM Team, GCN 43579; Sugai et al., GCN 43580; Roberts et al., GCN 43585; Frederiks et al., GCN 43590; Luo et al., GCN 43591; Li et al., GCN 43605) at ~0.914d and again at ~1.875d after the burst. A set of clear (roughly R) filter images were obtained. We detected the optical afterglow (Gompertz et al., GCN 43586; Lee et al., GCN 43587; Saccardi et al., GCN 43595; García García et al., GCN 43599, Shi et al. GCN 43601, Jayaraman et al., GCN 43606; Zhu et al., GCN 43607) in our coadd images and estimate the afterglow to be 17.8 +/- 0.1 and 19.2 +/- 0.2 mag (Vega) respectively. View this GCN Circular online at https://gcn.nasa.gov/circulars/43609. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41711] GRB 251230A: MeerLICHT afterglow detection
by GCN Circulars 03 Feb '26

03 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43608 SUBJECT: GRB 251230A: MeerLICHT afterglow detection DATE: 26/02/03 07:50:51 GMT FROM: Simon de Wet at DTU Space <simdewet(a)gmail.com> S. de Wet (DTU Space) and P.J. Groot (Radboud/UCT/SAAO) report on behalf of the MeerLICHT consortium: The 0.6m wide-field MeerLICHT optical telescope located in Sutherland, South Africa, obtained a repeating series of 60s exposures in the q,u,g,r,i,z filters following the detection of GRB 251230A by Swift (Lanava et al., GCN 43252). Our observations began 185 seconds after the Swift trigger and continued for approximately 26 minutes following the filter sequence quqgqrqiqz. A further four exposures were taken after a gap of approximately 30 minutes. We detect the bright optical afterglow in all of our images, and report the following first detections in each filter: q = 12.99 +/- 0.01 at 01:25:21 UT u = 13.95 +/- 0.05 at 01:26:41 UT g = 14.24 +/- 0.02 at 01:29:24 UT r = 14.43 +/- 0.01 at 01:32:07 UT i = 14.67 +/- 0.01 at 01:34:51 UT z = 14.80 +/- 0.03 at 01:37:36 UT We measure a power-law decline rate of -1.54 in the q-band. A light curve is available at the following link: https://raw.githubusercontent.com/simdewet/GRB_lightcurves/main/GRB251230A.… MeerLICHT is built and run by a consortium consisting of Radboud University, University of Cape Town, the South African Astronomical Observatory, the University of Oxford, the University of Manchester and the University of Amsterdam. View this GCN Circular online at https://gcn.nasa.gov/circulars/43608. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41710] GRB 250131A: FTW optical and NIR observations
by GCN Circulars 02 Feb '26

02 Feb '26

TITLE: GCN CIRCULAR NUMBER: 43607 SUBJECT: GRB 250131A: FTW optical and NIR observations DATE: 26/02/02 22:00:00 GMT FROM: Ziyuan.Zhu(a)campus.lmu.de Ziyuan Zhu (LMU), Malte Busmann (LMU), Julius Gassert (LMU), Xander J. Hall (CMU), Brendan O’Connor (CMU), Daniel Gruen (LMU), and Antonella Palmese (CMU) report: We observed the counterpart of GRB 260131A (Fermi/GBM Team, GCN 43579; Frederiks et al., GCN 43590; Luo et al., GCN 43591; Li et al., GCN 43605) with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i, and J bands for 15x 120s, starting at 2026-02-01T22:14:35 UT, (1.65 days after the trigger). We detect the counterpart in all bands and measure an r-band magnitude of r = 19.18 +/- 0.03 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/43607. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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