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

[vsnet-grb-info 42014] GRB 251130B: TERI Gamma-ray detection
by GCN Circulars 02 Mar '26

02 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43897 SUBJECT: GRB 251130B: TERI Gamma-ray detection DATE: 26/03/02 15:52:59 GMT FROM: nicholasjkirschner(a)gmail.com Nicholas Kirschner (a), Daniel Shy (b), C.C. Cheung (b), Bernard Phlips (b), Michael Streicher (c), James Mason (c), Douglas M. Groves (c), Feng Zhang (c), and Willy Kaye (c) (a) National Research Council Research Associate resident at the U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (b) U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (c) H3D, Inc., 812 Avis Dr., Ann Arbor, MI 48108, USA The cadmium zinc TElluride Radiation Imager (TERI) gamma-ray telescope [1], operating on the International Space Station, reports the detection of GRB 251130B, which was also detected by Fermi/GBM (GCN 42905, 42907), AstroSat/CZTI (GCN 42925), and Glowbug (GCN 42953). Using 1 Hz binning, and adopting T0 = 2025-11-30T15:33:18, we observe the second of the two peaks seen in the Fermi/GBM lightcurve (GCN 42905) at ~T0+78.5s with a peak excess count rate of 276 counts per second (cps) above the 201 cps baseline rate observed in nearby off-source intervals. The analysis results presented here are preliminary and currently lack a detailed response function. TERI is an Office of Naval Research funded technology demonstrator for large-volume pixelated CdZnTe detectors developed, built, and operated by the U.S. Naval Research Laboratory (NRL) in conjunction with H3D, Inc. The pixelated CdZnTe detectors have an energy range of 40 keV to 3 MeV per pixel. It was launched on 2025 April 21 aboard the Department of Defense Space Test Program STP-H10 to the ISS. On the ISS, it is located on the SOX external payload facility on the Columbus module. Analysis of TERI data at NRL is supported by the Office of Naval Research 6.1. [1] Shy, Daniel, et al. "Development of the cadmium zinc TElluride Radiation Imager." Journal of Astronomical Telescopes, Instruments, and Systems 10.4 (2024): 044009-044009 (arXiv:2408.04559). Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/43897. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42013] GRB 260208A: TERI Gamma-ray detection
by GCN Circulars 02 Mar '26

02 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43896 SUBJECT: GRB 260208A: TERI Gamma-ray detection DATE: 26/03/02 15:52:13 GMT FROM: nicholasjkirschner(a)gmail.com Nicholas Kirschner (a), Daniel Shy (b), C.C. Cheung (b), Bernard Phlips (b), Michael Streicher (c), James Mason (c), Douglas M. Groves (c), Feng Zhang (c), and Willy Kaye (c) (a) National Research Council Research Associate resident at the U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (b) U.S. Naval Research Laboratory, 4555 Overlook Ave SW, Washington, DC 20375 (c) H3D, Inc., 812 Avis Dr., Ann Arbor, MI 48108, USA The cadmium zinc TElluride Radiation Imager (TERI) gamma-ray telescope [1], operating on the International Space Station, reports the detection of GRB 260208A, which was also detected by Fermi/GBM (GCN 43635, 43673), Fermi/LAT (GCN 43645), GECAM-B (GCN 43658), NuSTAR (GCN 43674), and Glowbug (GCN 43675). Using 1 Hz binning, we find a burst onset at T0 = 2026-02-08T05:07:28 and three emission peaks with excesses of 192, 165, and 130 counts per second (cps) above the 33.2 cps baseline rate observed in nearby off-source intervals, at ~T0+15.5s, 23.5s, and 35.5s, respectively. We use all counts between 40 keV and 3 MeV. The analysis results presented here are preliminary and currently lack a detailed response function. TERI is an Office of Naval Research funded technology demonstrator for large-volume pixelated CdZnTe detectors developed, built, and operated by the U.S. Naval Research Laboratory (NRL) in conjunction with H3D, Inc. The pixelated CdZnTe detectors have an energy range of 40 keV to 3 MeV per pixel. It was launched on 2025 April 21 aboard the Department of Defense Space Test Program STP-H10 to the ISS. On the ISS, it is located on the SOX external payload facility on the Columbus module. Analysis of TERI data at NRL is supported by the Office of Naval Research 6.1. [1] Shy, Daniel, et al. "Development of the cadmium zinc TElluride Radiation Imager." Journal of Astronomical Telescopes, Instruments, and Systems 10.4 (2024): 044009-044009 (arXiv:2408.04559). Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/43896. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42012] GRB 260302A: Fermi GBM Final Real-time Localization
by GCN Circulars 02 Mar '26

02 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43895 SUBJECT: GRB 260302A: Fermi GBM Final Real-time Localization DATE: 26/03/02 14:30:12 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 14:19:40 UT on 2 Mar 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260302A (trigger 794153985.446798 / 260302597). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 239.3, Dec = -61.8 (J2000 degrees, equivalent to J2000 15h 57m, -61d 47'), with a statistical uncertainty of 2.7 degrees. The angle from the Fermi LAT boresight is 20.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260302597/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260302597/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260302597/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43895. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42011] EP260227a: Mondy optical observations
by GCN Circulars 02 Mar '26

02 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43894 SUBJECT: EP260227a: Mondy optical observations DATE: 26/03/02 13:09:06 GMT FROM: Alina Volnova at IKI RAS <alinusss(a)gmail.com> A. Volnova (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (IKI) report on behalf of IKI-GRB-FuN: We observed the field of the fast X-ray transient EP260227a (Wang et al., GCN 43869) with the AZT-33IK 1.5m telescope of the Mondy observatory starting on 2026-02-28 (UT) 20:55:14 and taking several 90-seconds frames in the R band. The optical counterpart (Eyles-Ferris et al., GCNs 43867, 43877, 43888; Li et al., GCN 43868; Fu et al., GCN 43873; Mandarakas et al., GCN 43874; Eyles-Ferris and Tanvir, GCN 43875; Malesani et al., GCN 43876; Strausbaugh et al., GCN 43879; Bochenek et al., GCN 43880; Gassert et al., GCN 43881; Gupta et al., GCN 43884; Ma et al., GCN 43887; Zhong et al., GCN 43891) is barely detected in the stacked frame. Preliminary photometry and observational details are the following: Date UT start t-T0 Exp. Filter Obj. S/N UL(3 sigma) (mid,days) (n*s) (3sigma) 2026-02-28 20:55:14 1.05053 40*90 R 21.8 2.5 21.5 The photometry is based on several nearby stars from the USNO-B1 catalogue (R2 magnitudes) and is not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/43894. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42010] GRB 260228A: CAHA 2.2m telescope optical upper limit
by GCN Circulars 01 Mar '26

01 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43893 SUBJECT: GRB 260228A: CAHA 2.2m telescope optical upper limit DATE: 26/03/01 22:42:20 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct(a)iaa.es> S. Guziy (IAA-CSIC), Y.-D. Hu (GXU), M.D. Caballero-García, M. Gritsevich, I. Pérez-García, R. Sánchez-Ramírez, S-Y. Wu (IAA-CSIC), G. García-Segura (UNAM), M. Blazek, I. Vico (CAHA) and A.J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, report: Following the detection of GRB 260228A by SVOM/ECLAIRs (Julakanti et al., GCNC 43882), we triggered the 2.2 m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almería, Spain). Images were obtained starting on Mar. 1 at 03:34 UT (i.e., ~6.7 hours after the trigger) in the Sloan griz bands covering the entire error region. In the co-added images (60 × 6 s), no optical transient is detected down to limiting magnitudes of 22.1 mag (r') and 21.0 (i'). This non-detection is consistent with the reports from SVOM/VT (Li et al., GCNC 43886) and SVOM/COLIBRÍ (Mandarakas et al. GCNC 43892). We thank the staff at Calar Alto Observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/43893. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42009] GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
by GCN Circulars 01 Mar '26

01 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43892 SUBJECT: GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit DATE: 26/03/01 17:32:00 GMT FROM: nikos.mandarakas(a)lam.fr Nikos Mandarakas (LAM), Margarita Pereyra (UNAM), Nathaniel R. Butler (ASU), Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Jean-Luc Atteia (IRAP), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Edilberto Aguilar-Ruiz (UNAM), Camila Angulo (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Asuka Kuwata (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), Antonio de Ugarte Postigo (LAM), Yashaswi Julakanti, Rob Eyles-Ferris report: We imaged the field of the SVOM GRB 260228A (Julakanti et al., GCN Circ. 43882) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed from 2026-03-01 07:28 to 11:52 UTC (from 10.55 to 14.96 hours after the trigger) and obtained 120 minutes of exposure in the r filter and 129 minutes of exposure in the z filter. The data were reduced, coadded, calibrated, and analysed with the COLIBRÍ ASU pipeline. The photometry was calibrated using nearby stars from the Pan-STARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. In the stacked image, comparing to Pan-STARRS and Legacy Survey (Dey et al. 2019) images, we do not detect any new source within the ECLAIRs uncertainty region (Julakanti et al., GCN Circ. 43882) down to the following 5-sigma limits: r > 23.3 z > 22.5 This upper limit is consistent with the one reported by Li et al. (GCN Circ. 43886). We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. 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/43892. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42008] EP260227a: Mephisto optical detection
by GCN Circulars 01 Mar '26

01 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43891 SUBJECT: EP260227a: Mephisto optical detection DATE: 26/03/01 14:58:50 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Shiyan Zhong, Hongguang Li, Qinhao Shao, Yuan Fang, Jian Cui, Guowang Du, Yu Pan, Xingzhu Zou, Xinlei Chen, Brajesh Kumar, Jianghua Zhang, Edoardo P. Lagioia, Yuanpei Yang, Xiangkun Liu, Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team: The field of EP260227a (Wang et al., GCN 43869) was observed with the 1.6-meter Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at Lijiang Observatory. The simultaneous observations in Mephisto u/g/i bands were started from 2026-02-27T20:20:38 (~8 minutes after the trigger). The field was again simultaneously observed in v/r/z bands (starting from 2026-02-27T20:23:47). We detected a source at the position reported by Eyles-Ferris et. al. (GCN 43867) and other groups Li et al., (GCN 43868); Fu et al, (GCN 43873); Mandarakas et al., (GCN 43874); Eyles-Ferris and Tanvir et al., (GCN 43875); Malesani et al., (GCN 43876); Eyles-Ferris et al., (GCN 43877); Strausbaugh et al., (GCN 43879); Bochenek et al., (GCN 43880); Gassert et al., (GCN 43881); Gupta et al., (GCN 43884); Ma et al., (GCN 43887) and Eyles-Ferris et al., (GCN 43888). The preliminary photometry results (without extinction correction) are listed below: Start_Time (UT) | Band | Exp(s) | Mag/LimMag(AB) --------------------|------|--------|-------------------- 2026-02-27T20:20:38 | u | 45 | >20.86 (3-sigma) 2026-02-27T20:20:38 | g | 45 | 20.58 +/- 0.32 2026-02-27T20:20:38 | i | 45 | 19.92 +/- 0.18 --------------------|------|--------|-------------------- 2026-02-27T20:23:47 | v | 45 | >20.80 (3-sigma) 2026-02-27T20:23:47 | r | 45 | 20.13 +/- 0.25 2026-02-27T20:23:47 | z | 45 | >20.28 (3-sigma) ------------------------------------------------------------------------------------------------- Mephisto (Multi-channel Photometric Survey Telescope) is a 1.6-m wide-field multi-channel telescope, the first of its type in the world, capable of imaging the same field of view in three optical bands simultaneously. It provides real-time, high-quality colors of stellar objects. The Mephisto mosaic cameras were installed in October 2025. The first light was achieved in all three channels on 10 October 2025, and these are currently in the commissioning phase. Here, we note that the current data processing pipeline is still at a preliminary stage, with flux calibration precision in each band at the level of about 5% or even higher. ------------------------------------------------------------------------------------------------- View this GCN Circular online at https://gcn.nasa.gov/circulars/43891. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42007] GRID detection of GRB 260225D
by GCN Circulars 01 Mar '26

01 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43890 SUBJECT: GRID detection of GRB 260225D DATE: 26/03/01 13:20:06 GMT FROM: GRID Student Team at Tsinghua University <grid(a)tsinghua.edu.cn> Longhao Li, Chenyu Wang, Zirui Yang report on behalf of the GRID Collaboration: GRID reports the detection of GRB 260225D, which was also observed by Glowbug (GCN #43856) and SVOM/GRM(GCN #43885). The event triggered GRID at T0 = 2026-02-25 19:51:28.7 UTC and was detected by both GRID-09B and GRID-11B, with a weaker signal observed by GRID-11B. Temporal analysis based on GRID-09B data yields a burst duration of T90 = 1.96 ± 0.08 s in the 30–2000 keV energy range. At present, only the GRID light curve is available. No spectral analysis is reported at this stage. The GRID light curve of this event can be found at https://mirrors.tuna.tsinghua.edu.cn/GRID/data/GRID-GCN/GRB260225D/GRID_260… GRID is a student-led project to monitor the transient gamma-ray sky with multiple detectors onboard different nanosatellites in the era of multi-messenger astronomy. For more information about GRID, please refer to: https://doi.org/10.1007/s10686-019-09636-w and https://doi.org/10.1007/s10686-021-09819-4. View this GCN Circular online at https://gcn.nasa.gov/circulars/43890. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42006] EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
by GCN Circulars 01 Mar '26

01 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43889 SUBJECT: EP-WXT trigger 01709258652: 50cm Telescope multi-band observations DATE: 26/03/01 13:18:28 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Yuan Fang, Hong Guang Li, Shiyan Zhong, Qinhao Shao, Jian Cui, Yu Pan, Xingzhu Zou, Xinlei Chen, Brajesh Kumar, Guowang Du, Jinghua Zhang, Xufeng Zhu, Tao Wang, Xinzhong Er, Yuanpei Yang, Xiangkun Liu, Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team: The 50cm Telescope of the Yunnan University was triggered on 2026-02-26T14:42:36 (~52.6 min after the EP/WXT trigger) to observe the field of EP-WXT trigger 01709258652 (Yang et al., GCN 43849; Wu et al., GCN 43857). A sequence of g, r, i and z-band images was obtained about 51 min. The photometry of suggested flare star LP 435-538 (High Proper Motion Star; Yang et al., GCN 43849) shows a decline from 14.41 to 14.89 mag (AB, calibrated against Gaia XP) in g-band over ~47 min. The fading was relatively gradual during this observation period. These results further support the previous finding by Wu et al. (GCN 43857) that EP X-ray trigger was associated with a stellar flare. The 50cm telescope is located at the Lijiang Observatory, China and is part of 50cm array facility. The camera employs an ON Semi KAF-50100 sensor, with 8176 x 6132 pixels of size 6μm (corresponding to 0.3 arcsec projected on the sky). The telescope is utilized for a prompt monitoring of transients and also serves as the supporting facility for monitoring the Mephisto detected targets (Chen et al. 2024, Yang et al. 2024). View this GCN Circular online at https://gcn.nasa.gov/circulars/43889. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 42005] EP260227a: further LCO observations
by GCN Circulars 01 Mar '26

01 Mar '26

TITLE: GCN CIRCULAR NUMBER: 43888 SUBJECT: EP260227a: further LCO observations DATE: 26/03/01 10:25:41 GMT FROM: Rob Eyles-Ferris at U of Leicester <raje1(a)leicester.ac.uk> R. A. J. Eyles-Ferris (Leicester), A. Martin-Carrillo (UCD), P. G. Jonker (Radboud), and J. Chacón (PUC) report on behalf of a larger collaboration: We observed the optical counterpart of the fast X-ray transient EP260227a (Wang et al., GCN 43869) with an LCO 1m telescope located at the Cerro Tololo Inter-American Observatory (Chile) equipped with the SINISTRO instrument. We obtained nine 300 s exposures in the r band from 2026-03-01 07:52:01 to 2026-03-01 08:43:10 UT (t_mid = 36.09 hr). In our stacked image, we clearly detect the optical counterpart (Eyles-Ferris et al., GCN 43867; Li et al., GCN 43868; Fu et al, GCN 43873; Mandarakas et al., GCN 43874; Eyles-Ferris and Tanvir et al., GCN 43875; Malesani et al., GCN 43876; Eyles-Ferris et al., GCN 43877; Strausbaugh et al., GCN 43879; Bochenek et al., GCN 43880; Gassert et al., GCN 43881; Gupta et al., GCN 43884; Ma et al., GCN 43887). We measure an AB magnitude of r = 22.82 +/- 0.28 calibrated to Pan-STARRS and not corrected for Galactic extinction. Our observations suggest there is no significant evolution since the observations of Gupta et al. (GCN 43884) ~12 hr earlier. View this GCN Circular online at https://gcn.nasa.gov/circulars/43888. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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