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

[vsnet-grb-info 40862] GRB 251121A: Glowbug gamma-ray detection of a likely short burst
by GCN Circulars 22 Nov '25

22 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42794 SUBJECT: GRB 251121A: Glowbug gamma-ray detection of a likely short burst DATE: 25/11/22 02:28:23 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> R. Woolf, C.C. Cheung, 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 251121A, which was also detected by Fermi/GBM (GCN 42790). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-11-21 16:30:57.936 with a duration of 0.06 s and a total significance of about 9.4 sigma. The light curve comprises a single peak. 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 telescopes 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/42794. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40861] EP251118a: Xinglong-2.16m optical observation
by GCN Circulars 22 Nov '25

22 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42793 SUBJECT: EP251118a: Xinglong-2.16m optical observation DATE: 25/11/22 01:34:51 GMT FROM: liuxing(a)nao.cas.cn X. Liu, J.J. Jin, J. Zheng, Z. Fan, D. Xu, L.B. He, J. An, S.Q. Jiang, Z.P. Zhu, J.J. Jia(NAOC), S.Y. Fu(HUST) report on behalf of a large collaboration: We observed the field of EP251118a detected by EP/WXT (Jiang et al., GCN 42749; Shi et al., GCN 42754;) and likely GRB 251118C (Frederiks et al., GCN 42765; Wang et al., GCN 42766; Delaunay et al., GCN 42770; Woolf et al, GCN 42771) using the Xinglong-2.16m telescope equipped with the BFOSC camera. Observations started at 19:28:32 UT on 2025-11-21 (i.e., 74.77 h after the EP trigger), and 15x300 s R-band frames have been obtained. The optical afterglow (Melasani et al., GCN 42751; An et al., GCN 42756; Belkin et al., GCN42758; Yadav et al., GCN 42760; Busmann et al., GCN 42763; Francile et al., GCN 42767; Rodríguez et al., GCN 42773; Li et al., GCN 42776; Lee et al., GCN 42780; Moskvitin et al., GCN 42785; Gupta et al., GCN42787) was cleary detected in our stacked frame with a magnitude of R = 22.1 +/- 0.1 at a mid-time of 75.28hr, calibrated with Pan-STARRS1 DR2 catalog converted using Lupton (2005) equations and not corrected for Galactic extinction. We thank the staff at Xinglong observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/42793. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40860] GRB 251115A: Fermi GBM Observation
by GCN Circulars 21 Nov '25

21 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42792 SUBJECT: GRB 251115A: Fermi GBM Observation DATE: 25/11/21 23:37:57 GMT FROM: Angus Jameson <abj0023(a)uah.edu> A. Jameson (UAH), S. Bala (USRA), and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 03:20:02.67 UT on 15 November 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251115A (trigger 784869607/251115139), which was also detected by Fermi-LAT (E. Bissaldi et al. 2025, GCN 42696). The Fermi GBM on-ground location is consistent with the Fermi-LAT position. The angle from the Fermi LAT boresight is 80 degrees. The GBM light curve consists of a double-peaked emission with a duration (T90) of about 13 s (50-300 keV). The time-averaged spectrum from T0-4.1 to T0+13.8 s is best fit by a Band function with Epeak = 36 +/- 6 keV, alpha = -0.7 +/- 0.4, and beta = -2.09 +/- 0.07. The event fluence (10-1000 keV) in this time interval is (3.5 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+0.064 s in the 10-1000 keV band is 9.0 +/- 0.3 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/42792. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40859] The EP-WXT trigger 01709248635 is likely a flaring star
by GCN Circulars 21 Nov '25

21 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42791 SUBJECT: The EP-WXT trigger 01709248635 is likely a flaring star DATE: 25/11/21 16:45:02 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y.-H. I. Yin (HKU), B.-T. Wang (YNAO), H.-Z. Wu (HUST) and W. D. Zhang (NAOC) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709248635 at the time of 2025-11-21T16:11:59, is likely a stellar flare associated with a T Tauri Star HD 285751. The estimated flux of the flare is around 1.0e-10 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 1.3e32 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/42791. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40858] GRB 251121A: Fermi GBM Final Real-time Localization
by GCN Circulars 21 Nov '25

21 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42790 SUBJECT: GRB 251121A: Fermi GBM Final Real-time Localization DATE: 25/11/21 16:41:36 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 16:30:58 UT on 21 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251121A (trigger 785435463.990588 / 251121688). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 250.6, Dec = -19.8 (J2000 degrees, equivalent to J2000 16h 42m, -19d 48'), with a statistical uncertainty of 19.5 degrees. The angle from the Fermi LAT boresight is 100.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251121688/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251121688/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251121688/… View this GCN Circular online at https://gcn.nasa.gov/circulars/42790. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40857] Fermi Gamma-ray Burst Monitor trigger 785388351 / 251121143 is not a GRB
by GCN Circulars 21 Nov '25

21 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42789 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 785388351 / 251121143 is not a GRB DATE: 25/11/21 14:57:14 GMT FROM: Peter Veres at University of Alabama in Huntsville <veresp(a)gmail.com> P. Veres (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 785388351 / 251121143 at 03:25:46.72 UT on 21 November 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to particle activity." View this GCN Circular online at https://gcn.nasa.gov/circulars/42789. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40856] Fermi trigger No 785388351: Global MASTER-Net observations report
by GCN Circulars 21 Nov '25

21 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42788 SUBJECT: Fermi trigger No 785388351: Global MASTER-Net observations report DATE: 25/11/21 14:45:55 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 GRB251121.14 (trigger No 785388351,21h 39m 12.00s , +42d 06m 36.0s, R=11.36) errorbox 39901 sec after notice time and 39938 sec after trigger time at 2025-11-21 14:31:24 UT, with upper limit up to 16.5 mag. Observations started at twilight. The observations began at zenith distance = 2 deg. The sun altitude is -9.1 deg. The galactic latitude b = -8 deg., longitude l = 90 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3048278 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 39968 | 2025-11-21 14:31:24 | MASTER-Kislovodsk | (21h 28m 33.86s , +41d 27m 00.7s) | C | 60 | 15.6 | 39968 | 2025-11-21 14:31:24 | MASTER-Kislovodsk | (21h 34m 49.78s , +41d 04m 07.6s) | C | 60 | 14.0 | 40048 | 2025-11-21 14:32:44 | MASTER-Kislovodsk | (21h 47m 06.83s , +43d 20m 11.1s) | C | 60 | 16.0 | 40048 | 2025-11-21 14:32:44 | MASTER-Kislovodsk | (21h 53m 30.83s , +42d 57m 01.9s) | C | 60 | 13.4 | 40227 | 2025-11-21 14:35:43 | MASTER-Kislovodsk | (21h 49m 03.50s , +41d 25m 22.5s) | C | 60 | 16.1 | 40227 | 2025-11-21 14:35:44 | MASTER-Kislovodsk | (21h 55m 10.89s , +41d 02m 46.0s) | C | 60 | 14.1 | 40308 | 2025-11-21 14:37:04 | MASTER-Kislovodsk | (21h 32m 22.61s , +39d 32m 55.4s) | C | 60 | 16.1 | 40308 | 2025-11-21 14:37:04 | MASTER-Kislovodsk | (21h 38m 18.31s , +39d 09m 16.6s) | C | 60 | 13.7 | 40388 | 2025-11-21 14:38:24 | MASTER-Kislovodsk | (21h 52m 03.41s , +39d 31m 14.7s) | C | 60 | 16.5 | 40388 | 2025-11-21 14:38:24 | MASTER-Kislovodsk | (21h 58m 00.63s , +39d 07m 52.4s) | C | 60 | 14.0 | 40474 | 2025-11-21 14:39:50 | MASTER-Kislovodsk | (21h 30m 34.79s , +41d 17m 12.7s) | C | 60 | 16.2 | 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/42788. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40855] EP251118A: 1.3m DFOT optical afterglow detection
by GCN Circulars 21 Nov '25

21 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42787 SUBJECT: EP251118A: 1.3m DFOT optical afterglow detection DATE: 25/11/21 12:03:39 GMT FROM: ANSHIKA GUPTA at ARIES <anshika05180(a)gmail.com> Anshika Gupta, Pankaj Pawar, Debolina Kar, Dhruv Jain, and Kuntal Misra (ARIES) report: We observed the field of EP251118A detected by the Einstein Probe (Jiang et al. 2025, GCN 42749) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2025-11-20 at 20:16:13 UT, i.e., ~ 2.14 days after the Einstein Probe trigger. We have taken multiple frames with an exposure time of 300 s in the R filter. We stacked the images after the alignment. We detect the optical counterpart in our stacked image within the error box of NOT (Malesani et al. 2025, GCN 42751). We obtain the following preliminary magnitude in the stacked image: Date Start_UT T_start-T0 (days) Filter Exp time (s) Magnitude ====================================================================== 2025-11-20 20:16:13 ~2.14 R 250s*18 21.15 +/- 0.25 Our detection is consistent with Malesani et al. 2025 (GCN 42751); Belkin et al. 2025 (GCN 42758);Yadav et al. 2025 (GCN 42760); Busmann et al. 2025 (GCN 42763); Francile et al. 2025 (GCN 42767); Rodríguez et al. 2025 (GCN 42773); Li et al. 2025 (GCN 42776); Lee et al. 2025 (GCN 42780); Moskvitin et al. 2025 (GCN 42785). The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the Gaia catalog. View this GCN Circular online at https://gcn.nasa.gov/circulars/42787. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40854] GRB 251118A: Swift/UVOT Detection
by GCN Circulars 20 Nov '25

20 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42786 SUBJECT: GRB 251118A: Swift/UVOT Detection DATE: 25/11/20 22:23:37 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251118A 31.3 ks after the Fermi trigger (GCN Circ. 42743). A fading source consistent with the XRT position (Osbourne et al., GCN Circ. 42782) is detected in the UVOT exposures. The preliminary UVOT position is: RA (J2000) = 10:14:01.01 = 160.00422 (deg.) Dec (J2000) = -34:31:21.1 = -34.52254 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 31521 52651 885 18.79+/-0.05 white 108251 159027 1113 20.11+/-0.10 v 31678 42929 845 18.60+/-0.19 v 108564 147691 662 >19.73 u 31363 52627 2489 18.41+/-0.05 u 107942 158555 1113 19.61+/-0.15 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.057 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/42786. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40853] EP251118a / GRB 251118C: SAO RAS optical observations
by GCN Circulars 20 Nov '25

20 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42785 SUBJECT: EP251118a / GRB 251118C: SAO RAS optical observations DATE: 25/11/20 21:15:01 GMT FROM: Alexander Moskvitin at SAO RAS <mosk(a)sao.ru> A. Moskvitin and O. Spiridonova (SAO RAS), report on behalf of GRB follow-up team We observed the field of the EP251118a discovered by Einstein Probe (Jiang et al., GCN 42749; Shi et al., GCN 42754, also detected with the other space observatories, Frederiks et al., GCN 42765; Wang et al., GCN 42766; DeLaunay et al., GCN 42770; Woolf et al., GCN 42771) with the 1-m SAO RAS telescope Zeiss-1000 equipped with the CCD-photometer. We obtained 9 x 300 sec. images Rc band on 2025.11.19T23:26:31--2025.11.20T03:08:31 (t_mid - T0 = 1.35766 d). The OT (Malesani et al., GCN 42751; An et al., GCN 42756; Belkin et al., GCN 42758; Busmann et al., GCN 42763; Francile et al., GCN 42767; Urquijo-Rodríguez et al., GCN 42773; Lee et al., GCN 42780; also detected in NIR; Yadav et al., GCN 42760) is clearly visible in our stacked image with the brightness of R = 21.24 +/- 0.07. Preliminary photometry is based on the nearby objects from SDSS (magnitudes converted with Lupton 2005 equations) and has not corrected for the Galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/42785. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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