December 2025 - vsnet-grb-info - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-grb-info 41344] EP251229a: Einstein Probe detection of an X-ray transient
by GCN Circulars 30 Dec '25

30 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43253 SUBJECT: EP251229a: Einstein Probe detection of an X-ray transient DATE: 25/12/30 01:49:26 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> B. T. Wang (YNAO, CAS), J. P. Chen (SYSU), D. Zhu, K. J. Zhang (YNU), Y. L. Wang (NAO, CAS; ICE, CSIC-IEEC) and Z. X. Ling (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 EP251229a. The transient triggered EP-WXT (ID: 01709250690) at 2025-12-29T19:58:49 (UTC). The WXT position of the source is R.A. =124.103 deg, DEC = 37.224 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. = 124.1057 deg, DEC = 37.2073 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 are 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/43253. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41343] EP251229a: Einstein Probe detection of an X-ray transient
by GCN Circulars 30 Dec '25

30 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43253 SUBJECT: EP251229a: Einstein Probe detection of an X-ray transient DATE: 25/12/30 01:49:26 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> B. T. Wang (YNAO, CAS), J. P. Chen (SYSU), D. Zhu, K. J. Zhang (YNU), Y. L. Wang (NAO, CAS; ICE, CSIC-IEEC) and Z. X. Ling (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 EP251229a. The transient triggered EP-WXT (ID: 01709250690) at 2025-12-29T19:58:49 (UTC). The WXT position of the source is R.A. =124.103 deg, DEC = 37.224 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. = 124.1057 deg, DEC = 37.2073 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 are 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/43253. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41342] GRB 251230A: Swift detection of a burst with a bright optical counterpart
by GCN Circulars 30 Dec '25

30 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43252 SUBJECT: GRB 251230A: Swift detection of a burst with a bright optical counterpart DATE: 25/12/30 01:48:56 GMT FROM: Simone Dichiara at Pennsylvania State University <sbd5667(a)psu.edu> S. Lanava (PSU), S. Dichiara (PSU) and R. Gupta (NASA GSFC) report on behalf of the Neil Gehrels Swift Observatory Team: At 01:21:41 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 251230A (trigger=1429020). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 179.894, +11.415 which is RA(J2000) = 11h 59m 35s Dec(J2000) = +11d 24' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a multiple-peaked structure with a duration of about 80 sec. The peak count rate was ~5000 counts/sec (15-350 keV), at ~30 sec after the trigger. The XRT began observing the field at 01:22:49.3 UT, 68.1 seconds after the BAT trigger. Using promptly downlinked data we find a bright, fading, uncatalogued X-ray source with an enhanced position: RA, Dec 179.89781, 11.43828 which is equivalent to: RA(J2000) = 11h 59m 35.47s Dec(J2000) = +11d 26' 17.8" with an uncertainty of 1.9 arcseconds (radius, 90% containment). This location is 84 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at https://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density in excess of the Galactic value (1.88 x 10^20 cm^-2, Willingale et al. 2013), with an excess column of 4.4 (+1.47/-1.34) x 10^21 cm^-2 (90% confidence). The initial flux in the 2.5 s image was 4.73e-09 erg cm^-2 s^-1 (0.2-10 keV). UVOT took a finding chart exposure of 150 seconds with the White filter starting 76 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 11:59:35.42 = 179.89760 DEC(J2000) = +11:26:19.3 = 11.43870 with a 90%-confidence error radius of about 0.74 arc sec. This position is 4.7 arc sec. from the center of the XRT error circle. The estimated magnitude is 13.74 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.024. Burst Advocate for this burst is S. Lanava (sml7284 AT psu.edu) Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/43252. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41341] GRB 251226A: Glowbug gamma-ray detection
by GCN Circulars 29 Dec '25

29 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43251 SUBJECT: GRB 251226A: Glowbug gamma-ray detection DATE: 25/12/29 14:51:57 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 251226A, which was also detected by GECAM-B, SVOM/GRM, and HXMT (GCN 43244, 43245). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-12-26 08:01:02.528 with a duration of 9.2 s and a total significance of about 15.9 sigma. The light curve comprises a single peak corresponding to the initial brightest peak seen in the GECAM-B and SVOM/GRM light curves. The burst originated toward the Nadir side of Glowbug and was detected despite passing through the passive material from the H9 pallet and internal passive material/shielding within Glowbug. The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/43251. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41340] GRB 251222A/EP251222b: 1.6m Mephisto optical followup
by GCN Circulars 29 Dec '25

29 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43250 SUBJECT: GRB 251222A/EP251222b: 1.6m Mephisto optical followup DATE: 25/12/29 11:31:46 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Brajesh Kumar, Shiyan Zhong, Guowang Du, Hongguang Li, Dan Zhu, Yu Pan, Yuan Fang, Xingzhu Zou, Xinlei Chen, Xufeng Zhu, Tao Wang, Jinghua Zhang, Yehao Cheng, Xinzhong Er, Yuanpei Yang, Xiangkun Liu, Xiaowei Liu (SWIFAR, YNU) report on behalf of the Mephisto Team: We observed GRB 251222A/EP251222b (SVOM burst-id sb25122206, Yang et al. GCN 43188; Fermi/GBM, GCN 43186; EP-WXT, Guo et al., GCN 43201) with the 1.6m Multi-channel Photometric Survey Telescope (Mephisto) of Yunnan University located at the Lijiang Observatory. Multi-band (ugi and vrz) simultaneous observations were acquired in two sets using the newly installed three mosaic cameras. The first set (in ugi bands) and the second set (in vrz and ugi bands) of observations were started from 17:11:08T2025-12-22 (~5 min after the SVOM trigger) and 17:48:08T2025-12-22, respectively. These observations were continued till 2025-12-22T19:23:19. The optical counterpart reported previously (Palmerio et al., GCN 43189; An et. al, GCN 43194; Calapai et. al, GCN 43195; Durbak et. al, GCN 43197; Li et. al, GCN 43203; Saccardi et. al, GCN 43208; Gupta et. al, GCN 43207 GCN 43224; Saccardi et. al, GCN 43204; Kumar et. al, GCN 43209; Pérez-Fournon et. al, GCN 43212; Globus et al., GCN 43225; Pankov et al., GCN 43226; Freeberg et al., GCN 43229; Volnova et al., GCN 43230; Busmann et al., GCN 43233; Lee et al., GCN 43236; Maksut et al., GCN 43237) was clearly detected in our vgriz bands but not in u band. Although our first set of observations is limited, the overall preliminary light curves indicate a decay trend during ~300 - 2500 sec and a rise afterward. The preliminary photometric magnitudes of initial frames are listed below. These magnitudes are not corrected for the Galactic extinction in the direction of the burst. ------------------------------------------------------------------ Start_Time(UT) |Band | Exp(s)| Mag/LimMag (AB) ---------------------|------|-------|----------------------------- 2025-12-22T17:11:08 | u | 45*2 | >20.85 2025-12-22T17:48:08 | v | 60*3 | 21.41 +/- 0.32 2025-12-22T17:11:11 | g | 45 | 18.28 +/- 0.05 2025-12-22T17:48:10 | r | 60 | 19.18 +/- 0.08 2025-12-22T17:11:11 | i | 45 | 17.60 +/- 0.03 2025-12-22T17:48:10 | z | 60 | 19.02 +/- 0.23 ------------------------------------------------------------------ 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. The facility is operated by the South-Western Institute for Astronomy Research (SWIFAR), Yunnan University. 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 presently, these are under the commissioning phase. All the data have been reduced by the Mephisto data processing pipeline. 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/43250. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41339] GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
by GCN Circulars 28 Dec '25

28 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43249 SUBJECT: GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC DATE: 25/12/28 16:36:39 GMT FROM: Antonio de Ugarte Postigo at LAM, CNRS <adeugartepostigo(a)gmail.com> A. de Ugarte Postigo (LAM), A. Martin-Carrillo (UCD), L. Izzo (INAF/OACN and DARK/NBI), B. Schneider (LAM), D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), C. C. Thoene (AbAO), N. R. Tanvir (Univ. Leicester), J. F. Agui Fernandez (CAHA), M. A. Aloy (UV), J. P. U. Fynbo (DAWN/NBI), L. Galbany (IEEC-CSIC), S. Geier (GTC), G. Lombardi (GTC), N. A. Rakotondrainibe (LAM), A. Cabrera-Lavers (GTC), report: We have continued monitoring the optical counterpart (Angulo et al. GCN 42880) of GRB 251129A (Wenjun et al. GCN 42877) using the 10.4 m Gran Telescopio Canarias (GTC) equipped with OSIRIS+ and HiPERCAM. We observed the afterglow in imaging using the u, g, r, i, z bands on 8 December 2025 (9.2 day after the burst) and again on 26 December 2025 (27.2 day after the burst). The optical counterpart is well detected in both epochs, with an increase in brightness in all bands. At 27.2 days after the burst, we measure r = 22.24 +/- 0.04 mag. The object is significantly brighter than the candidate host underlying the GRB, which we measure at r ~ 24.16 mag in CFHT archival images. On 27 December 2025, 28.1 days after the burst, we obtained a 3x1200 s spectrum using OSIRIS+ equipped with grism R1000B, covering the range between 3700 and 7780 AA at a resolving power of ~600. The spectrum shows a continuum over the full spectral range. We do not detect any of the spectral features reported by Sánchez-Ramírez et al. (GCN 42900) at z = 1.460. However, we detect emission features of [OII], [OIII], H-alpha, H-beta and H-gamma from an underlying galaxy at a common redshift of z = 0.505. At a redshift of z = 0.505, the emergence of a detectable SN is expected, which explains the rebrightening observed in our photometric data. Hence, we suggest that the redshift of GRB 251129A is indeed z = 0.505 and that we are now observing the associated SN. We do note that the observed emission is brighter than what we would expect for a template of SN 1998bw at z = 0.505, even after correction of host galaxy contribution, although our photometry may be affected by the remaining light of the afterglow. We encourage further follow-up of this event. This work has used the GRBspec database at http://grbspec.eu (de Ugarte Postigo et al. 2014, doi:10.1117/12.2055774). View this GCN Circular online at https://gcn.nasa.gov/circulars/43249. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41338] Fermi GRB 251228A: Global MASTER-Net observations report
by GCN Circulars 28 Dec '25

28 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43248 SUBJECT: Fermi GRB 251228A: Global MASTER-Net observations report DATE: 25/12/28 05:15:35 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 251228A ( Fermi GBM team, GCN 43246) errorbox 4566 sec after notice time and 4601 sec after trigger time at 2025-12-28 01:58:51 UT, with upper limit up to 17.7 mag. The observations began at zenith distance = 14 deg. The sun altitude is -28.7 deg. The galactic latitude b = 51 deg., longitude l = 166 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3087807 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 4631 | 2025-12-28 01:58:51 | MASTER-Kislovodsk | (10h 04m 18.19s , +50d 46m 44.1s) | C | 60 | 17.2 | 4631 | 2025-12-28 01:58:51 | MASTER-Kislovodsk | (09h 57m 14.55s , +51d 07m 25.1s) | C | 60 | 17.5 | 4723 | 2025-12-28 02:00:23 | MASTER-Kislovodsk | (09h 59m 11.64s , +48d 50m 59.9s) | C | 60 | 17.0 | 4725 | 2025-12-28 02:00:25 | MASTER-Kislovodsk | (09h 52m 24.48s , +49d 12m 11.6s) | C | 60 | 17.4 | 4829 | 2025-12-28 02:02:09 | MASTER-Kislovodsk | (09h 45m 17.93s , +50d 44m 48.3s) | C | 60 | 17.2 | 4829 | 2025-12-28 02:02:09 | MASTER-Kislovodsk | (09h 38m 14.89s , +51d 05m 43.5s) | C | 60 | 17.3 | 4922 | 2025-12-28 02:03:42 | MASTER-Kislovodsk | (10h 17m 30.25s , +48d 53m 01.1s) | C | 60 | 17.0 | 4922 | 2025-12-28 02:03:42 | MASTER-Kislovodsk | (10h 10m 42.22s , +49d 14m 15.0s) | C | 60 | 17.4 | 5018 | 2025-12-28 02:05:17 | MASTER-Kislovodsk | (09h 50m 33.43s , +52d 39m 46.6s) | C | 60 | 17.1 | 5018 | 2025-12-28 02:05:18 | MASTER-Kislovodsk | (09h 43m 11.63s , +53d 00m 12.0s) | C | 60 | 17.3 | 5337 | 2025-12-28 02:10:37 | MASTER-Kislovodsk | (10h 04m 06.83s , +50d 46m 06.6s) | C | 60 | 17.5 | 5337 | 2025-12-28 02:10:37 | MASTER-Kislovodsk | (09h 57m 01.40s , +51d 05m 30.2s) | C | 60 | 17.3 | 5429 | 2025-12-28 02:12:08 | MASTER-Kislovodsk | (09h 59m 08.41s , +48d 52m 46.4s) | C | 60 | 17.7 | 5429 | 2025-12-28 02:12:08 | MASTER-Kislovodsk | (09h 52m 19.73s , +49d 12m 21.2s) | C | 60 | 17.3 | 5523 | 2025-12-28 02:13:43 | MASTER-Kislovodsk | (09h 45m 15.46s , +50d 45m 29.2s) | C | 60 | 17.3 | 5523 | 2025-12-28 02:13:43 | MASTER-Kislovodsk | (09h 38m 11.21s , +51d 04m 53.5s) | C | 60 | 17.0 | 5619 | 2025-12-28 02:15:19 | MASTER-Kislovodsk | (10h 17m 21.80s , +48d 51m 08.9s) | C | 60 | 17.3 | 5619 | 2025-12-28 02:15:19 | MASTER-Kislovodsk | (10h 10m 32.65s , +49d 10m 46.8s) | C | 60 | 17.3 | 5717 | 2025-12-28 02:16:57 | MASTER-Kislovodsk | (09h 50m 31.71s , +52d 39m 11.2s) | C | 60 | 17.5 | 5717 | 2025-12-28 02:16:57 | MASTER-Kislovodsk | (09h 43m 09.29s , +52d 58m 26.3s) | C | 60 | 17.0 | 5816 | 2025-12-28 02:18:36 | MASTER-Kislovodsk | (10h 10m 16.22s , +52d 41m 00.0s) | C | 60 | 17.4 | 5816 | 2025-12-28 02:18:36 | MASTER-Kislovodsk | (10h 02m 52.62s , +53d 00m 22.2s) | C | 60 | 17.1 | 5914 | 2025-12-28 02:20:14 | MASTER-Kislovodsk | (09h 55m 09.39s , +46d 56m 17.6s) | C | 60 | 17.2 | 5914 | 2025-12-28 02:20:14 | MASTER-Kislovodsk | (09h 48m 36.78s , +47d 16m 10.0s) | C | 60 | 17.0 | 6009 | 2025-12-28 02:21:49 | MASTER-Kislovodsk | (10h 04m 12.28s , +50d 46m 34.1s) | C | 60 | 17.4 | 6010 | 2025-12-28 02:21:50 | MASTER-Kislovodsk | (09h 57m 07.42s , +51d 06m 00.2s) | C | 60 | 17.3 | 6529 | 2025-12-28 02:30:29 | MASTER-Kislovodsk | (10h 17m 24.80s , +48d 52m 37.6s) | C | 60 | 17.1 | 6529 | 2025-12-28 02:30:29 | MASTER-Kislovodsk | (10h 10m 29.17s , +49d 12m 12.1s) | C | 60 | 17.1 | 6625 | 2025-12-28 02:32:04 | MASTER-Kislovodsk | (09h 50m 35.30s , +52d 39m 13.1s) | C | 60 | 17.1 | 6625 | 2025-12-28 02:32:04 | MASTER-Kislovodsk | (09h 43m 06.45s , +52d 58m 20.9s) | C | 60 | 17.0 | 6721 | 2025-12-28 02:33:40 | MASTER-Kislovodsk | (10h 10m 16.53s , +52d 38m 50.2s) | C | 60 | 17.4 | 6721 | 2025-12-28 02:33:41 | MASTER-Kislovodsk | (10h 02m 46.74s , +52d 58m 01.9s) | C | 60 | 16.9 | 6817 | 2025-12-28 02:35:17 | MASTER-Kislovodsk | (09h 55m 16.58s , +46d 56m 01.5s) | C | 60 | 17.0 | 6818 | 2025-12-28 02:35:17 | MASTER-Kislovodsk | (09h 48m 38.37s , +47d 15m 51.9s) | C | 60 | 17.1 | 6917 | 2025-12-28 02:36:56 | MASTER-Kislovodsk | (10h 04m 11.56s , +50d 46m 10.2s) | C | 60 | 17.6 | 6917 | 2025-12-28 02:36:56 | MASTER-Kislovodsk | (09h 57m 00.57s , +51d 05m 34.7s) | C | 60 | 17.0 | 7013 | 2025-12-28 02:38:33 | MASTER-Kislovodsk | (09h 59m 12.42s , +48d 50m 02.1s) | C | 60 | 17.6 | 7013 | 2025-12-28 02:38:33 | MASTER-Kislovodsk | (09h 52m 19.00s , +49d 09m 39.2s) | C | 60 | 17.3 | 7112 | 2025-12-28 02:40:12 | MASTER-Kislovodsk | (09h 45m 14.59s , +50d 45m 25.6s) | C | 60 | 17.3 | 7112 | 2025-12-28 02:40:12 | MASTER-Kislovodsk | (09h 38m 05.16s , +51d 04m 52.0s) | C | 60 | 17.1 | 7211 | 2025-12-28 02:41:50 | MASTER-Kislovodsk | (10h 17m 23.46s , +48d 51m 25.4s) | C | 60 | 17.0 | 7211 | 2025-12-28 02:41:50 | MASTER-Kislovodsk | (10h 10m 28.94s , +49d 11m 03.4s) | C | 60 | 17.0 | 7303 | 2025-12-28 02:43:23 | MASTER-Kislovodsk | (09h 50m 26.54s , +52d 39m 48.9s) | C | 60 | 17.1 | 7304 | 2025-12-28 02:43:23 | MASTER-Kislovodsk | (09h 42m 58.14s , +52d 59m 02.1s) | C | 60 | 16.9 | 7400 | 2025-12-28 02:45:00 | MASTER-Kislovodsk | (10h 10m 20.94s , +52d 39m 34.4s) | C | 60 | 17.4 | 7400 | 2025-12-28 02:45:00 | MASTER-Kislovodsk | (10h 02m 51.64s , +52d 58m 42.7s) | C | 60 | 17.2 | 7497 | 2025-12-28 02:46:37 | MASTER-Kislovodsk | (10h 10m 37.66s , +52d 39m 35.2s) | C | 60 | 12.4 | 7497 | 2025-12-28 02:46:37 | MASTER-Kislovodsk | (10h 03m 48.11s , +52d 58m 42.0s) | C | 60 | 12.5 | 7596 | 2025-12-28 02:48:16 | MASTER-Kislovodsk | (10h 04m 13.05s , +50d 44m 13.4s) | C | 60 | 17.4 | 7596 | 2025-12-28 02:48:16 | MASTER-Kislovodsk | (09h 57m 03.22s , +51d 03m 35.3s) | C | 60 | 17.2 | 7688 | 2025-12-28 02:49:47 | MASTER-Kislovodsk | (09h 59m 10.08s , +48d 51m 01.6s) | C | 60 | 17.5 | 7693 | 2025-12-28 02:49:53 | MASTER-Kislovodsk | (09h 52m 17.21s , +49d 10m 37.4s) | C | 60 | 17.3 | 7789 | 2025-12-28 02:51:29 | MASTER-Kislovodsk | (09h 45m 10.11s , +50d 43m 08.7s) | C | 60 | 17.4 | 7789 | 2025-12-28 02:51:29 | MASTER-Kislovodsk | (09h 38m 01.62s , +51d 02m 36.5s) | C | 60 | 17.1 | 7886 | 2025-12-28 02:53:06 | MASTER-Kislovodsk | (10h 17m 25.04s , +48d 51m 56.3s) | C | 60 | 17.3 | 7886 | 2025-12-28 02:53:06 | MASTER-Kislovodsk | (10h 10m 30.87s , +49d 11m 36.2s) | C | 60 | 17.1 | 7982 | 2025-12-28 02:54:42 | MASTER-Kislovodsk | (09h 50m 24.96s , +52d 38m 17.5s) | C | 60 | 17.5 | 7982 | 2025-12-28 02:54:42 | MASTER-Kislovodsk | (09h 42m 57.33s , +52d 57m 33.9s) | C | 60 | 17.1 | 8081 | 2025-12-28 02:56:20 | MASTER-Kislovodsk | (10h 10m 11.14s , +52d 40m 06.1s) | C | 60 | 17.4 | 8081 | 2025-12-28 02:56:20 | MASTER-Kislovodsk | (10h 02m 42.12s , +52d 59m 17.2s) | C | 60 | 17.3 | 8180 | 2025-12-28 02:57:59 | MASTER-Kislovodsk | (09h 55m 12.19s , +46d 55m 29.4s) | C | 60 | 17.2 | 8180 | 2025-12-28 02:57:59 | MASTER-Kislovodsk | (09h 48m 35.03s , +47d 15m 37.7s) | C | 60 | 17.0 | 8586 | 2025-12-28 03:04:46 | MASTER-Kislovodsk | (10h 17m 18.67s , +48d 51m 29.6s) | C | 60 | 17.1 | 8586 | 2025-12-28 03:04:46 | MASTER-Kislovodsk | (10h 10m 24.95s , +49d 11m 15.6s) | C | 60 | 17.1 | 8683 | 2025-12-28 03:06:23 | MASTER-Kislovodsk | (09h 50m 27.29s , +52d 37m 39.4s) | C | 60 | 17.1 | 8683 | 2025-12-28 03:06:23 | MASTER-Kislovodsk | (09h 43m 00.39s , +52d 57m 00.0s) | C | 60 | 17.1 | 8780 | 2025-12-28 03:08:00 | MASTER-Kislovodsk | (10h 10m 07.36s , +52d 37m 32.7s) | C | 60 | 17.4 | 8780 | 2025-12-28 03:08:00 | MASTER-Kislovodsk | (10h 02m 39.26s , +52d 56m 48.2s) | C | 60 | 17.3 | 8878 | 2025-12-28 03:09:37 | MASTER-Kislovodsk | (10h 10m 28.03s , +52d 37m 34.5s) | C | 60 | 12.6 | 8964 | 2025-12-28 03:11:03 | MASTER-Kislovodsk | (10h 12m 23.19s , +52d 37m 37.7s) | C | 60 | 12.3 | 9055 | 2025-12-28 03:12:35 | MASTER-Kislovodsk | (10h 12m 40.99s , +46d 55m 07.8s) | C | 60 | 17.4 | 9056 | 2025-12-28 03:12:35 | MASTER-Kislovodsk | (10h 06m 03.32s , +47d 15m 13.0s) | C | 60 | 17.4 | 9149 | 2025-12-28 03:14:09 | MASTER-Kislovodsk | (10h 23m 06.85s , +50d 45m 12.8s) | C | 60 | 16.9 | 9154 | 2025-12-28 03:14:14 | MASTER-Kislovodsk | (10h 15m 55.96s , +51d 04m 45.2s) | C | 60 | 17.1 | 9252 | 2025-12-28 03:15:51 | MASTER-Kislovodsk | (09h 56m 46.97s , +54d 31m 51.5s) | C | 60 | 17.1 | 9252 | 2025-12-28 03:15:52 | MASTER-Kislovodsk | (09h 48m 58.93s , +54d 50m 53.6s) | C | 60 | 17.1 | 9346 | 2025-12-28 03:17:26 | MASTER-Kislovodsk | (09h 37m 26.63s , +46d 54m 36.9s) | C | 60 | 17.2 | 9346 | 2025-12-28 03:17:26 | MASTER-Kislovodsk | (09h 30m 52.56s , +47d 15m 10.2s) | C | 60 | 17.2 | 9444 | 2025-12-28 03:19:04 | MASTER-Kislovodsk | (10h 10m 12.18s , +52d 38m 01.4s) | C | 60 | 17.0 | 9444 | 2025-12-28 03:19:04 | MASTER-Kislovodsk | (10h 02m 44.12s , +52d 57m 20.4s) | C | 60 | 17.2 | 9532 | 2025-12-28 03:20:31 | MASTER-Kislovodsk | (10h 10m 51.42s , +52d 38m 02.1s) | C | 60 | 12.5 | 9532 | 2025-12-28 03:20:31 | MASTER-Kislovodsk | (10h 02m 52.79s , +52d 57m 16.2s) | C | 60 | 13.0 | 9727 | 2025-12-28 03:23:46 | MASTER-Kislovodsk | (10h 12m 38.78s , +46d 54m 03.4s) | C | 60 | 17.3 | 9727 | 2025-12-28 03:23:46 | MASTER-Kislovodsk | (10h 06m 01.84s , +47d 14m 22.2s) | C | 60 | 17.4 | 9838 | 2025-12-28 03:25:37 | MASTER-Kislovodsk | (10h 23m 05.28s , +50d 45m 00.9s) | C | 60 | 16.5 | 9838 | 2025-12-28 03:25:37 | MASTER-Kislovodsk | (10h 15m 55.30s , +51d 04m 37.3s) | C | 60 | 17.1 | 9938 | 2025-12-28 03:27:18 | MASTER-Kislovodsk | (09h 56m 44.01s , +54d 31m 10.7s) | C | 60 | 16.9 | 9938 | 2025-12-28 03:27:18 | MASTER-Kislovodsk | (09h 48m 57.16s , +54d 50m 21.4s) | C | 60 | 17.1 | 10035 | 2025-12-28 03:28:55 | MASTER-Kislovodsk | (10h 02m 38.82s , +45d 21m 03.2s) | C | 60 | 17.2 | 10035 | 2025-12-28 03:28:55 | MASTER-Kislovodsk | (10h 09m 00.78s , +45d 00m 24.6s) | C | 60 | 17.3 | 10131 | 2025-12-28 03:30:30 | MASTER-Kislovodsk | (10h 29m 50.64s , +52d 37m 23.2s) | C | 60 | 16.3 | 10131 | 2025-12-28 03:30:30 | MASTER-Kislovodsk | (10h 22m 22.44s , +52d 56m 41.9s) | C | 60 | 16.8 | 10425 | 2025-12-28 03:35:24 | MASTER-Kislovodsk | (10h 12m 34.39s , +46d 54m 15.9s) | C | 60 | 16.4 | 10425 | 2025-12-28 03:35:25 | MASTER-Kislovodsk | (10h 05m 58.49s , +47d 14m 53.3s) | C | 60 | 17.1 | 10525 | 2025-12-28 03:37:05 | MASTER-Kislovodsk | (10h 22m 54.27s , +50d 44m 24.8s) | C | 60 | 16.2 | 10525 | 2025-12-28 03:37:05 | MASTER-Kislovodsk | (10h 15m 45.45s , +51d 04m 05.3s) | C | 60 | 16.8 | 10625 | 2025-12-28 03:38:45 | MASTER-Kislovodsk | (10h 23m 30.87s , +47d 14m 23.6s) | C | 60 | 16.5 | 10625 | 2025-12-28 03:38:45 | MASTER-Kislovodsk | (10h 30m 07.84s , +46d 54m 02.6s) | C | 60 | 15.8 | 10723 | 2025-12-28 03:40:23 | MASTER-Kislovodsk | (10h 02m 34.91s , +45d 21m 28.3s) | C | 60 | 16.7 | 10723 | 2025-12-28 03:40:23 | MASTER-Kislovodsk | (10h 08m 55.83s , +45d 00m 49.5s) | C | 60 | 16.3 | 10822 | 2025-12-28 03:42:02 | MASTER-Kislovodsk | (10h 29m 51.19s , +52d 36m 51.2s) | C | 60 | 15.5 | 10822 | 2025-12-28 03:42:02 | MASTER-Kislovodsk | (10h 22m 23.72s , +52d 56m 14.6s) | C | 60 | 16.2 | 10919 | 2025-12-28 03:43:39 | MASTER-Kislovodsk | (10h 09m 41.91s , +54d 51m 05.3s) | C | 60 | 16.2 | 10919 | 2025-12-28 03:43:39 | MASTER-Kislovodsk | (10h 17m 29.19s , +54d 31m 54.0s) | C | 60 | 15.6 | 11205 | 2025-12-28 03:48:25 | MASTER-Kislovodsk | (10h 22m 53.42s , +50d 43m 55.8s) | C | 60 | 15.1 | 11205 | 2025-12-28 03:48:25 | MASTER-Kislovodsk | (10h 15m 44.95s , +51d 03m 36.9s) | C | 60 | 16.1 | 11323 | 2025-12-28 03:50:23 | MASTER-Kislovodsk | (10h 23m 29.69s , +47d 13m 59.1s) | C | 60 | 16.1 | 11323 | 2025-12-28 03:50:23 | MASTER-Kislovodsk | (10h 30m 06.25s , +46d 53m 23.4s) | C | 60 | 15.2 | 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/43248. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41337] The EP-WXT trigger 01709250662 is likely a flaring star
by GCN Circulars 28 Dec '25

28 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43247 SUBJECT: The EP-WXT trigger 01709250662 is likely a flaring star DATE: 25/12/28 01:29:14 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin (HKU), J. P. Feng, B. Zhang (USTC), H. C. Ding, T. Wu (AHNU), D. Z. Du (ZJU), R. X. Hu (WHU), and W. D. Zhang (NAO,CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709250662 at the time of 2025-12-27T16:37:01, is likely a stellar flare associated with PM J11474+6644. The estimated flux of the flare is around 1.8×10^(-10) erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 9.5×10^30 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/43247. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41336] GRB 251228A: Fermi GBM Final Real-time Localization
by GCN Circulars 28 Dec '25

28 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43246 SUBJECT: GRB 251228A: Fermi GBM Final Real-time Localization DATE: 25/12/28 00:52:53 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 00:42:10 UT on 28 Dec 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251228A (trigger 788575335.25706 / 251228029). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 150.2, Dec = 49.8 (J2000 degrees, equivalent to J2000 10h 00m, 49d 47'), with a statistical uncertainty of 10.7 degrees. The angle from the Fermi LAT boresight is 107.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251228029/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251228029/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251228029/… View this GCN Circular online at https://gcn.nasa.gov/circulars/43246. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 41335] GRB 251226A: SVOM/GRM observation
by GCN Circulars 27 Dec '25

27 Dec '25

TITLE: GCN CIRCULAR NUMBER: 43245 SUBJECT: GRB 251226A: SVOM/GRM observation DATE: 25/12/27 17:34:44 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Wen-Jun Tan, Xue-Yuan Zao, Yue Huang, Shi-Jie Zheng, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Olivier GODET (IRAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight GRB 251226A (SVOM trigger reference: sb25122601) at 2025-12-26T08:01:05.000 UTC (T0), which is also detected by GECAM-B (Wang et al., GCN#43244) and HXMT. With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of a precursor followed by a main emission with a T90 of 58.7 +9.0/-9.4 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251226A.png In addition, the position of this burst, as determined by GECAM-B (RA= 260.2, DEC= 47.0, ERR=9.1), is located at about 125 degrees from the SVOM optical axis, which is outside the ECLAIRs field of view. With this localization, the time-averaged spectrum from T0-3 to T0+100 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.29 +0.22/-0.19 and the cutoff energy, parameterized as Epeak, is 632 +279/-146 keV. The event fluence (10-1000 keV) in this time interval is (4.33 +0.20/-0.21)E-05 erg/cm^2. The 1s peak spectrum, measured from T0+3 to T0+4 s, is also best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.18 +0.27/-0.20 and the cutoff energy, parameterized as Epeak, is 1520 +122/-56 keV. The flux (10-1000 keV) in this time interval is (2.61 +0.17/-0.17)E-06 erg/cm^2/s. The localization of GRB 251226A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251226A_amati.png And the localization in the 'Yonetoku' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251226A_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: Chen-Wei Wang (IHEP)(cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/43245. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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