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

[vsnet-grb-info 42820] Fermi trigger No 801135305: Global MASTER-Net observations report
by GCN Circulars 22 May '26

22 May '26

TITLE: GCN CIRCULAR NUMBER: 44692 SUBJECT: Fermi trigger No 801135305: Global MASTER-Net observations report DATE: 26/05/22 09:45:51 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), C.Francile, 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 GRB260522.40 (trigger No 801135305,18h 40m 52.08s , -25d 33m 00.0s, R=7.7) errorbox 88 sec after notice time and 124 sec after trigger time at 2026-05-22 09:37:04 UT, with upper limit up to 18.4 mag. The observations began at zenith distance = 57 deg. The sun altitude is -28.5 deg. The galactic latitude b = -10 deg., longitude l = 9 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3331401 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 134 | 2026-05-22 09:37:04 | MASTER-OAGH | (18h 37m 12.05s , -25d 49m 53.1s) | C | 20 | 17.7 | 169 | 2026-05-22 09:37:04 | MASTER-OAGH | (18h 37m 12.06s , -25d 49m 53.1s) | C | 90 | 18.0 | Coadd 170 | 2026-05-22 09:37:34 | MASTER-OAGH | (18h 37m 06.41s , -25d 50m 55.7s) | C | 30 | 17.9 | 215 | 2026-05-22 09:38:15 | MASTER-OAGH | (18h 37m 10.52s , -25d 50m 55.1s) | C | 40 | 17.6 | 270 | 2026-05-22 09:39:05 | MASTER-OAGH | (18h 37m 08.18s , -25d 49m 24.5s) | C | 50 | 18.0 | 270 | 2026-05-22 09:39:05 | MASTER-OAGH | (18h 45m 29.90s , -26d 25m 48.5s) | C | 50 | 18.4 | 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/44692. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42819] Fermi GRB 260522A: Global MASTER-Net observations report
by GCN Circulars 22 May '26

22 May '26

TITLE: GCN CIRCULAR NUMBER: 44691 SUBJECT: Fermi GRB 260522A: Global MASTER-Net observations report DATE: 26/05/22 09:15:54 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), C.Francile, 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 260522A ( Fermi GBM team, GCN 44687) errorbox 20242 sec after notice time and 20291 sec after trigger time at 2026-05-22 07:53:20 UT, with upper limit up to 18.8 mag. The observations began at zenith distance = 81 deg. The sun altitude is -37.9 deg. The galactic latitude b = -40 deg., longitude l = 86 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3330735 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 20321 | 2026-05-22 07:53:20 | MASTER-OAGH | (22h 29m 21.04s , +17d 30m 10.0s) | C | 60 | 17.6 | 20736 | 2026-05-22 08:00:14 | MASTER-OAGH | (22h 31m 10.56s , +15d 35m 11.4s) | C | 60 | 17.8 | 20961 | 2026-05-22 08:04:00 | MASTER-OAGH | (22h 44m 59.44s , +19d 24m 13.9s) | C | 60 | 17.6 | 21293 | 2026-05-22 08:09:31 | MASTER-OAGH | (22h 37m 34.70s , +18d 07m 52.6s) | C | 60 | 18.5 | 21293 | 2026-05-22 08:09:31 | MASTER-OAGH | (22h 45m 20.15s , +17d 30m 06.7s) | C | 60 | 17.7 | 21552 | 2026-05-22 08:13:50 | MASTER-OAGH | (22h 47m 01.86s , +15d 35m 01.0s) | C | 60 | 17.6 | 21552 | 2026-05-22 08:13:50 | MASTER-OAGH | (22h 39m 21.07s , +16d 12m 47.8s) | C | 60 | 18.5 | 21807 | 2026-05-22 08:18:05 | MASTER-OAGH | (22h 31m 54.37s , +12d 23m 27.9s) | C | 60 | 18.2 | 21807 | 2026-05-22 08:18:05 | MASTER-OAGH | (22h 39m 27.63s , +11d 45m 47.0s) | C | 60 | 17.9 | 21879 | 2026-05-22 08:19:17 | MASTER-OAGH | (22h 27m 00.97s , +14d 18m 45.6s) | C | 60 | 18.8 | 21879 | 2026-05-22 08:19:17 | MASTER-OAGH | (22h 34m 37.36s , +13d 41m 11.6s) | C | 60 | 18.3 | 21965 | 2026-05-22 08:20:43 | MASTER-OAGH | (22h 42m 42.24s , +14d 19m 33.9s) | C | 60 | 18.5 | 21965 | 2026-05-22 08:20:43 | MASTER-OAGH | (22h 50m 18.96s , +13d 41m 45.4s) | C | 60 | 17.5 | 22042 | 2026-05-22 08:22:00 | MASTER-OAGH | (22h 53m 22.36s , +20d 01m 39.3s) | C | 60 | 18.4 | 22042 | 2026-05-22 08:22:00 | MASTER-OAGH | (23h 01m 12.71s , +19d 23m 51.7s) | C | 60 | 17.6 | 22189 | 2026-05-22 08:24:27 | MASTER-OAGH | (22h 53m 34.68s , +18d 06m 41.9s) | C | 60 | 18.5 | 22189 | 2026-05-22 08:24:27 | MASTER-OAGH | (23h 01m 19.97s , +17d 28m 52.6s) | C | 60 | 17.6 | 22410 | 2026-05-22 08:28:08 | MASTER-OAGH | (22h 38m 08.15s , +10d 29m 27.1s) | C | 60 | 18.7 | 22410 | 2026-05-22 08:28:08 | MASTER-OAGH | (22h 45m 38.44s , +09d 51m 42.6s) | C | 60 | 18.1 | 22633 | 2026-05-22 08:31:52 | MASTER-OAGH | (22h 47m 29.08s , +12d 24m 15.1s) | C | 60 | 18.6 | 22634 | 2026-05-22 08:31:52 | MASTER-OAGH | (22h 55m 02.26s , +11d 46m 29.2s) | C | 60 | 17.6 | 22713 | 2026-05-22 08:33:12 | MASTER-OAGH | (22h 55m 14.36s , +16d 11m 27.2s) | C | 60 | 18.3 | 22713 | 2026-05-22 08:33:12 | MASTER-OAGH | (23h 02m 54.91s , +15d 33m 41.2s) | C | 60 | 17.8 | 22938 | 2026-05-22 08:36:56 | MASTER-OAGH | (23h 09m 34.33s , +20d 00m 02.3s) | C | 60 | 18.6 | 23357 | 2026-05-22 08:43:56 | MASTER-OAGH | (22h 58m 25.81s , +14d 18m 37.0s) | C | 60 | 18.5 | 23357 | 2026-05-22 08:43:56 | MASTER-OAGH | (23h 06m 02.72s , +13d 40m 58.6s) | C | 60 | 17.9 | 23430 | 2026-05-22 08:45:08 | MASTER-OAGH | (23h 01m 03.75s , +09d 52m 16.5s) | C | 60 | 17.9 | 23430 | 2026-05-22 08:45:08 | MASTER-OAGH | (22h 53m 33.23s , +10d 29m 56.5s) | C | 60 | 18.4 | 23607 | 2026-05-22 08:48:05 | MASTER-OAGH | (23h 03m 00.46s , +12d 23m 19.5s) | C | 60 | 18.2 | 23607 | 2026-05-22 08:48:05 | MASTER-OAGH | (23h 10m 33.91s , +11d 45m 40.8s) | C | 60 | 17.8 | 23679 | 2026-05-22 08:49:17 | MASTER-OAGH | (23h 11m 07.56s , +16d 12m 42.7s) | C | 60 | 18.2 | 23679 | 2026-05-22 08:49:17 | MASTER-OAGH | (23h 18m 48.36s , +15d 35m 03.0s) | C | 60 | 17.5 | 23760 | 2026-05-22 08:50:39 | MASTER-OAGH | (22h 45m 45.40s , +08d 34m 28.4s) | C | 60 | 18.5 | 23760 | 2026-05-22 08:50:39 | MASTER-OAGH | (22h 53m 13.26s , +07d 57m 00.4s) | C | 60 | 18.5 | 24000 | 2026-05-22 08:54:38 | MASTER-OAGH | (23h 14m 05.04s , +14d 17m 27.5s) | C | 60 | 18.1 | 24073 | 2026-05-22 08:55:51 | MASTER-OAGH | (23h 09m 34.28s , +18d 06m 37.0s) | C | 60 | 18.6 | 24073 | 2026-05-22 08:55:51 | MASTER-OAGH | (23h 17m 19.72s , +17d 29m 07.5s) | C | 60 | 18.1 | 24253 | 2026-05-22 08:58:51 | MASTER-OAGH | (23h 09m 06.45s , +10d 28m 56.4s) | C | 60 | 18.7 | 24253 | 2026-05-22 08:58:51 | MASTER-OAGH | (23h 16m 37.32s , +09d 51m 15.3s) | C | 60 | 18.4 | 24325 | 2026-05-22 09:00:04 | MASTER-OAGH | (23h 01m 10.70s , +08d 36m 20.3s) | C | 60 | 18.6 | 24325 | 2026-05-22 09:00:04 | MASTER-OAGH | (23h 08m 39.11s , +07d 58m 43.5s) | C | 60 | 18.2 | 24618 | 2026-05-22 09:04:56 | MASTER-OAGH | (23h 18m 37.97s , +12d 23m 55.7s) | C | 60 | 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/44691. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42818] EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
by GCN Circulars 22 May '26

22 May '26

TITLE: GCN CIRCULAR NUMBER: 44690 SUBJECT: EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp DATE: 26/05/22 08:38:05 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> R. D. Liang, W. X. Li, D. Y. Li, C. C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: We report the detection of a sub-threshold X-ray transient, EP260518a, associated with the optical transient AT 2026ndp. EP260518a was detected by the Wide-field X-ray Telescope (WXT) aboard the Einstein Probe (EP) mission at R.A. = 299.034 deg, Dec. = -48.618 deg (J2000), with an uncertainty radius of 3 arcmin, at 2026-05-18 13:44:21 UTC. The measured 0.5–4 keV flux was approximately 2.5 x 10^-11 erg cm^-2 s^-1. Due to the low signal-to-noise ratio, no significant flare-like feature is apparent in the X-ray light curve. A candidate optical counterpart, AT 2026ndp, was identified through real-time cross-matching. The transient was discovered by ATLAS at 2026-05-19 07:44:02.400 UTC, approximately 17 hours after the WXT detection, with a c-band magnitude of 18.73 +/- 0.10. There is a faint point-like source in Legacy Survey dr10, which is 1.8 arcsec away. Follow-up observations were performed with the Follow-up X-ray Telescope (FXT) aboard EP, starting at 2026-05-21 08:23:08 UTC (~66 hr after the WXT detection). An uncatalogued X-ray source was detected within the WXT error region at R.A. = 299.0407 deg, Dec. = -48.6362 deg (J2000), with an uncertainty of 10 arcsec. The FXT position is offset by 4.7 arcsec from the optical counterpart. The FXT spectrum can be fitted with an absorbed power-law model with a photon index of 2.5 (+0.8/-0.7) and hydrogen column density of 2.3 (+2.0/-1.7) x 10^21 cm^-2. The estimated average 0.3–10 keV flux is around 4.6 (+1.9/-1.2) 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/44690. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42817] GRB 260522A: Fermi-LAT detection
by GCN Circulars 22 May '26

22 May '26

TITLE: GCN CIRCULAR NUMBER: 44689 SUBJECT: GRB 260522A: Fermi-LAT detection DATE: 26/05/22 08:24:21 GMT FROM: Elisabetta Bissaldi at Politecnico and INFN Bari <elisabetta.bissaldi(a)ba.infn.it> At 02:15:08 UT on May 22nd, 2026, Fermi-LAT detected high-energy emission from GRB 260522A, which was also detected by Fermi-GBM (trigger 801108913 / 260522094, GCN #44687). The best LAT on-ground location is found to be RA, Dec = 346.67, 9.66 (J2000) with an error radius of 0.55 deg (90 % containment, statistical error only). This was 15 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 - 50 s after the GBM trigger is (2.89 ± 0.97)E-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.14 ± 0.38. The highest-energy photon is a 820 MeV event, which is observed 1.3 seconds after the GBM trigger. The Fermi-LAT point of contact for this burst is Elisabetta Bissaldi (elisabetta.bissaldi(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/44689. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42816] GRB 260519C: SVOM/GRM observation
by GCN Circulars 22 May '26

22 May '26

TITLE: GCN CIRCULAR NUMBER: 44688 SUBJECT: GRB 260519C: SVOM/GRM observation DATE: 26/05/22 06:32:44 GMT FROM: renyz16607(a)163.com SVOM/GRM team: Yang-Zhao Ren, Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Feliu Lacreu (IAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 260519C (SVOM trigger reference: sb26051904) at 2026-05-19T13:45:38.000 UTC (T0), which is also detected by Konus-Wind (Svinkin, GCN #44677), and NuSTAR (Waratkar et al., GCN #44672). 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 26.5 +1.0/-1.0 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260519C.png With this localization, the time-averaged spectrum from T0-5 to T0+30 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -0.78 +0.08/-0.09 and the cutoff energy, parameterized as Epeak, is 135 +7/-6 keV. The event fluence (10-1000 keV) in this time interval is (2.07 +0.07/-0.06)E-05 erg/cm^2. The 1s peak spectrum, measured from T0+12.5 to T0+13.5 s, if fitted by a power law function with an exponential high-energy cutoff, the power law index is -0.60 +0.19/-0.20 and the cutoff energy, parameterized as Epeak, is 93.47 +6.95/-5.93 keV. The flux (10-1000 keV) in this time interval is (1.10 +0.21/-0.06)E-06 erg/cm^2/s. The localization of GRB 260519C in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260519C_amati.png The localization of GRB 260519C in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb260519C_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 point of contact for this burst is: Yang-Zhao Ren (IHEP)(renyz(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/44688. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42815] GRB 260522A: Fermi GBM Final Real-time Localization
by GCN Circulars 22 May '26

22 May '26

TITLE: GCN CIRCULAR NUMBER: 44687 SUBJECT: GRB 260522A: Fermi GBM Final Real-time Localization DATE: 26/05/22 02:25:32 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 02:15:08 UT on 22 May 2026, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 260522A (trigger 801108913.782424 / 260522094). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 343.6, Dec = 14.1 (J2000 degrees, equivalent to J2000 22h 54m, 14d 05'), with a statistical uncertainty of 5.1 degrees. The angle from the Fermi LAT boresight is 10.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260522094/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260522094/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2026/bn260522094/… View this GCN Circular online at https://gcn.nasa.gov/circulars/44687. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42814] GRB 260511A: iTelescope T-75 optical detection
by GCN Circulars 21 May '26

21 May '26

TITLE: GCN CIRCULAR NUMBER: 44686 SUBJECT: GRB 260511A: iTelescope T-75 optical detection DATE: 26/05/21 22:55:39 GMT FROM: Takanori Sakamoto at AGU <tsakamoto(a)phys.aoyama.ac.jp> H. Ban, T. Kato, K. Hotta, Y. Kawakubo, M. Serino, T. Sakamoto (AGU) We observed the field of GRB 260511A detected by the Fermi/GBM (Fermi GBM Team, GCN Circ. 44529), the SVOM/ECLAIRs (Godet et al., GCN Circ. 44532), the NuSTAR CsI anti-coincidence shields (Waratkar et al., GCN Circ. 44555), the Konus-Wind (Ridnaia et al., GCN Circ. 44585), the Glowbug (Woolf et al., GCN Circ. 44586), and the GRID (Li et al., GCN Circ. 44664) with the iTelescope.Net (http://www.itelescope.net) T75 (ASAN250) telescope located at Rio Hurtado Valley, Chile. We took 20 images of 60 sec exposures in the Red filter starting from May 11 at 06:37:27 (UT), about 24 minutes after the Fermi/GBM trigger and stopped at 07:07:42. The afterglow (Jiang et al., GCN Circ. 44533; Akl et al., GCN Circ. 44534; Saccardi et al., GCN Circ. 44535; Zheng et al., GCN Circ. 44536; Wu et al., GCN Circ. 44538; Harper et al., GCN Circ. 44545; Brivio et al., GCN Circ. 44562; Li et al., GCN Circ. 44575; Fu et al., GCN Circ. 44579; Zhu et al., GCN Circ. 44584) is detected in the stacked image of the first eight images (total exposure of 480 s) collected between 06:37:27 and 06:49:12. The afterglow magnitude is 19.3 +- 0.6 using the USNO-B1 catalog. No afterglow was detected in the following twelve images collected between 06:49:44 and 07:07:42. The 5-sigma upper limit of the stacked image of the last twelve images (total exposure of 720 s) is 18.3 mag. View this GCN Circular online at https://gcn.nasa.gov/circulars/44686. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42813] GRB 260520B: SVOM/GRM observation
by GCN Circulars 21 May '26

21 May '26

TITLE: GCN CIRCULAR NUMBER: 44685 SUBJECT: GRB 260520B: SVOM/GRM observation DATE: 26/05/21 15:23:56 GMT FROM: yzh807926(a)163.com SVOM/GRM team: Zheng-Hang Yu, Chen-Wei Wang, Chao Zheng, 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 260520B at 2026-05-20T09:35:53.000 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #44676). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a main episode with a single peak a T90 of 6.0 +7.0/-5.0 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb260520B.png In addition, the position of this burst, as determined by Fermi/GBM (RA= 346.68 deg, DEC= 39.68 deg, ERR=14.4 deg, GCN#44425), is located at about 94 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. 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: Zheng-Hang Yu (IHEP)(zhyu(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/44685. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42812] GRB 260411B: TERI Gamma-ray detection
by GCN Circulars 21 May '26

21 May '26

TITLE: GCN CIRCULAR NUMBER: 44684 SUBJECT: GRB 260411B: TERI Gamma-ray detection DATE: 26/05/21 14:08:14 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 260411B, which was also detected by Fermi GBM (GCN 44262, 44266), SVOM/GRM (GCN 44268), Fermi LAT (GCN 44277), GECAM (GCN 44285), Glowbug (GCN 44312), and Konus-Wind (GCN 44332). Using 1 Hz binning, and adopting T0 = 2026-04-11T08:04:43.568 Z, we observe one peak at T0+1.5s, with peak excess count rate of 69 above the 192 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/44684. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 42811] GRB 260407A: TERI Gamma-ray detection
by GCN Circulars 21 May '26

21 May '26

TITLE: GCN CIRCULAR NUMBER: 44683 SUBJECT: GRB 260407A: TERI Gamma-ray detection DATE: 26/05/21 14:07:39 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 260407A, which was also detected by Fermi/GBM (GCN 44226), Glowbug (GCN 44237), CALET (GCN 44242), InsightHXMT/HE (GCN 44245), and GECAM-A (GCN 44246). Using 1 Hz binning, and adopting T0 = 2026-04-07T09:11:06.112Z, we observe one peak at T0+1.5s, with peak excess count rate of 45 above the 133 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/44683. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0