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[vsnet-grb-info 40768] SVOM GRB251116.66: Global MASTER-Net observations report
by GCN Circulars 16 Nov '25

16 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42704 SUBJECT: SVOM GRB251116.66: Global MASTER-Net observations report DATE: 25/11/16 16:56:29 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-Tunka robotic telescope [1] located in Russia (Applied Physics Institute, Irkutsk State University) was pointed to the SVOM GRB251116.66 (trigger No 1763308636,22h 21m 03.65s , -10d 24m 37.8s, R=0.1302) errorbox 25 sec after notice time and 310 sec after trigger time at 2025-11-16 16:02:26 UT, with upper limit up to 13.6 mag. The observations began at zenith distance = 83 deg. The sun altitude is -56.4 deg. The galactic latitude b = -51 deg., longitude l = 52 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3043922 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 341 | 2025-11-16 16:02:26 | MASTER-Tunka | (22h 21m 03.35s , -10d 19m 13.2s) | P- | 60 | 13.6 | 341 | 2025-11-16 16:02:26 | MASTER- | (22h 20m 46.89s , -10d 14m 22.2s) | C | 60 | 16.6 | 404 | 2025-11-16 16:03:30 | MASTER-Tunka | (22h 21m 03.18s , -10d 19m 14.1s) | P- | 60 | 13.3 | 405 | 2025-11-16 16:03:30 | MASTER- | (22h 20m 45.91s , -10d 14m 11.5s) | C | 60 | 16.6 | 468 | 2025-11-16 16:04:33 | MASTER-Tunka | (22h 21m 03.13s , -10d 19m 13.7s) | P- | 60 | 13.4 | 468 | 2025-11-16 16:04:33 | MASTER- | (22h 20m 45.80s , -10d 14m 11.6s) | C | 60 | 16.4 | 532 | 2025-11-16 16:05:37 | MASTER-Tunka | (22h 21m 03.20s , -10d 19m 09.1s) | P- | 60 | 13.5 | 532 | 2025-11-16 16:05:37 | MASTER- | (22h 20m 45.69s , -10d 14m 13.4s) | C | 60 | 16.3 | 596 | 2025-11-16 16:06:42 | MASTER-Tunka | (22h 21m 02.88s , -10d 19m 13.7s) | P- | 60 | 13.0 | 596 | 2025-11-16 16:06:42 | MASTER- | (22h 20m 45.81s , -10d 14m 10.6s) | C | 60 | 16.3 | 660 | 2025-11-16 16:07:45 | MASTER-Tunka | (22h 21m 02.81s , -10d 19m 14.0s) | P- | 60 | 13.3 | 723 | 2025-11-16 16:08:49 | MASTER-Tunka | (22h 21m 02.83s , -10d 19m 13.6s) | P- | 60 | 13.1 | 723 | 2025-11-16 16:08:49 | MASTER- | (22h 20m 45.60s , -10d 14m 12.6s) | C | 60 | 16.3 | 794 | 2025-11-16 16:09:59 | MASTER-Tunka | (22h 21m 02.55s , -10d 19m 16.7s) | P- | 60 | 13.0 | 794 | 2025-11-16 16:09:59 | MASTER- | (22h 20m 45.36s , -10d 14m 16.4s) | C | 60 | 16.3 | 857 | 2025-11-16 16:11:03 | MASTER-Tunka | (22h 21m 02.58s , -10d 19m 14.6s) | P- | 60 | 12.3 | 857 | 2025-11-16 16:11:03 | MASTER- | (22h 20m 45.53s , -10d 14m 12.8s) | C | 60 | 16.2 | 921 | 2025-11-16 16:12:07 | MASTER-Tunka | (22h 21m 02.72s , -10d 19m 10.5s) | P- | 60 | 13.1 | 921 | 2025-11-16 16:12:07 | MASTER- | (22h 20m 44.78s , -10d 14m 31.2s) | C | 60 | 16.3 | 985 | 2025-11-16 16:13:10 | MASTER-Tunka | (22h 21m 02.34s , -10d 19m 15.4s) | P- | 60 | 12.5 | 1068 | 2025-11-16 16:14:34 | MASTER-Tunka | (22h 21m 02.35s , -10d 19m 11.9s) | P- | 60 | 12.7 | 1132 | 2025-11-16 16:15:37 | MASTER-Tunka | (22h 21m 02.11s , -10d 19m 15.6s) | P- | 60 | 12.4 | 1132 | 2025-11-16 16:15:37 | MASTER- | (22h 20m 43.68s , -10d 14m 23.0s) | C | 60 | 16.2 | 1195 | 2025-11-16 16:16:41 | MASTER-Tunka | (22h 21m 01.96s , -10d 19m 17.1s) | P- | 60 | 12.0 | 1322 | 2025-11-16 16:18:48 | MASTER-Tunka | (22h 21m 01.71s , -10d 19m 17.4s) | P- | 60 | 12.0 | 1323 | 2025-11-16 16:18:48 | MASTER- | (22h 20m 43.97s , -10d 14m 36.1s) | C | 60 | 15.9 | 1386 | 2025-11-16 16:19:51 | MASTER-Tunka | (22h 21m 01.46s , -10d 19m 21.7s) | P- | 60 | 12.0 | 1450 | 2025-11-16 16:20:55 | MASTER-Tunka | (22h 21m 01.38s , -10d 19m 19.5s) | P- | 60 | 12.3 | 1577 | 2025-11-16 16:23:02 | MASTER-Tunka | (22h 21m 01.10s , -10d 19m 17.9s) | P- | 60 | 12.3 | 1641 | 2025-11-16 16:24:06 | MASTER-Tunka | (22h 21m 01.02s , -10d 19m 18.5s) | P- | 60 | 12.0 | 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/42704. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40767] GRB 251116C: SVOM detection of a burst
by GCN Circulars 16 Nov '25

16 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42703 SUBJECT: GRB 251116C: SVOM detection of a burst DATE: 25/11/16 16:22:19 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Pillas (IAP), M.G. Bernardini (INAF-OAB, LUPM), M. Brunet (IRAP), A. Saccardi (CEA/Irfu), report on behalf of the SVOM mission team: At 2025-11-16T15:57:41 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251116C (SVOM burst-id sb25111605). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 3 alerts. IMT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 12.47 in the [5-20] keV energy band over a time window of 40.96 seconds starting at 2025-11-16T15:57:36. The localization of the best alert is R.A., Dec. 335.3182, -10.4239 degrees: R.A. (J2000) = 22h21m16.37s Dec. (J2000) = -10d25m26.01s with a 90% confidence level (C.L.) radius of 6.49 arcmin (including systematic error of 2 arcmin added in quadrature). SVOM slewed to the burst. No X-ray observation could be performed by SVOM/MXT for the time being. No optical observation could be performed by SVOM/VT for the time being. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Marion Pillas: marion.pillas(a)iap.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/42703. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40766] GRB 251116B: SVOM detection of a burst
by GCN Circulars 16 Nov '25

16 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42702 SUBJECT: GRB 251116B: SVOM detection of a burst DATE: 25/11/16 16:10:05 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> M. Pillas (IAP), M.G. Bernardini (INAF-OAB, LUPM), M. Brunet (IRAP), report on behalf of the SVOM mission team: At 2025-11-16T15:32:36 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251116B (SVOM burst-id sb25111604). The following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was only detected by the Count-Rate Trigger (CRT), which produced a sequence of 1 alert. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 6.67 in the [8-120] keV energy band over a time window of 10.20 seconds starting at 2025-11-16T15:32:26. The localization of the best alert is R.A., Dec. 18.8320, -41.0854 degrees: R.A. (J2000) = 1h15m19.68s Dec. (J2000) = -41d05m07.42s with a 90% confidence level (C.L.) radius of 11.72 arcmin (including systematic error of 2 arcmin added in quadrature). Due to the detection significance being below the slew threshold, no immediate slew was performed on this burst. Further observations by SVOM/VT are currently scheduled. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. SVOM/ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. SVOM/GRM was developed by the Institute of High Energy Physics (IHEP) of CAS. SVOM/MXT was developed jointly by CNES, CEA-IRFU, CNRS-IJCLab, University of Leicester, MPE. The Burst Advocate (BA) on shift for this alert is Marion Pillas: marion.pillas(a)iap.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/42702. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40765] IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 16 Nov '25

16 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42701 SUBJECT: IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube DATE: 25/11/16 03:42:55 GMT FROM: Sam Hori at IceCube/U Wisc-Madison <sahori(a)wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-Cascade 251112A (https://gcn.gsfc.nasa.gov/notices_amon_icecube_cascade/141589_6342606.amon) in a time range of 1000 seconds centered on the alert event time (2025-11-12 16:25:42.310 UTC to 2025-11-12 16:42:22.310 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, 3 track-like events are found within the 90% containment region of IceCube-Cascade 251112A. We find that these additional 3 events are well described by atmospheric background expectations, with a p-value of 0.97. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 1.3e-01 to 2.4e+01 GeV cm^-2 within the 90% spatial containment region of IceCube-Cascade 251112A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 2e+02 GeV and 4e+06 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2025-11-11 16:34:02.310 UTC to 2025-11-13 16:34:02.310 UTC). In this case, we report a p-value of 0.21, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, ranges from 1.5e-01 to 2.5e+01 GeV cm^-2 within the 90% spatial containment region of IceCube-Cascade 251112A in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/42701. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40764] GRB 251116A: Fermi GBM Final Real-time Localization
by GCN Circulars 16 Nov '25

16 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42700 SUBJECT: GRB 251116A: Fermi GBM Final Real-time Localization DATE: 25/11/16 02:10:44 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 02:00:04 UT on 16 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251116A (trigger 784951209.245526 / 251116083). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 27.3, Dec = -24.8 (J2000 degrees, equivalent to J2000 01h 49m, -24d 48'), with a statistical uncertainty of 4.5 degrees. The angle from the Fermi LAT boresight is 30.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251116083/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251116083/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251116083/… View this GCN Circular online at https://gcn.nasa.gov/circulars/42700. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40763] LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42699 SUBJECT: LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap DATE: 25/11/15 21:10:03 GMT FROM: antier(a)ijclab.in2p3.fr P. Hello (IJCLAB), D. Akl (NYUAD), S. Antier (IJCLAB), A. Klotz (IRAP), M. Mazek (FZU), M. Pillas (IAP), O. Pyshna (Caltech), C. Andrade (UMN), M. Coughlin (UMN), C. Douzet (IJCLAB), S. Karpov (FZU), T. duLaz (Caltech), R. LeMontagner (IJCLAB), C. Limonta (OCA), Y. Rajabov (UBAI), D. Turpin (CEA-AIM) on behalf of the GRANDMA collaboration: We observed the S251112cm (Initial, as provided by GCN 42650, LVK collaboration) sky localization area with wide field telescopes TAROT/TRE, TAROT/TCH, TAROT/TCA, FRAM-FZU,together with the 60 cm telescope at Les Makes Observatory. Observations started at 2025-11-12 17:14 UTC, e.g 1h56 after the trigger time and during 14h. We used the SkyPortal application (skyportal.io) and associated services to monitor this observational campaign (Coughlin et al. 2018, 2023). Our sensivity map of the GW sky localization area has been computed using Pillas et al., 2025 and is accessible at https://grandma-owncloud.ijclab.in2p3.fr/index.php/s/TqGach7PpbM4d3K. We covered 22% of the Initial sky localization area (Bayestar, GCN 42650 LVK collaboration) and 16% of the Updated sky localization area (Bilby, GCN 2690, LVK collaboration). Preliminary analysis did not reveal any clear candidate that can be associated to the event (with limit magnitudes ranging from 17 to 21 mag in r-band at 5 sigma). We re-conducted a second epoch of observations the day after. All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2025). Images obtained were calibrated using the PanSTARRS DR1 catalog. We are currently investigating candidates reported by other collaborations. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). View this GCN Circular online at https://gcn.nasa.gov/circulars/42699. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40762] LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42698 SUBJECT: LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA DATE: 25/11/15 13:54:03 GMT FROM: Yodgor Rajabov at UBAI <rajabov(a)astrin.uz> O. Burkhonov, Y. Rajabov, Y. Tillayev (UBAI), P. Hello (IJCLAB), A. Klotz (IRAP), M. Coughlin (UMN), S. Karpov (FZU), M. Pillas (IAP), M. Mazek (FZU ), S. Antier (IJCLAB), O. Pyshna (Caltech) on behalf of GRANDMA: We detected transient event 2025adht in RA_J2000=12:00:24.3431, Dec_J2000=+49:02:51.7 reported by (GCN 42677 Anand et al., Franz GCN 42675 et al.,). Observations were carried out at the 1.5-meter telescope Maidanak Observatory by using 4Kx4K SNUCAM CCD. All observations were taken using a Bessel R filter. The observations started at 2025-11-15T00:13:15 UTC and ended at 2025-11-15T00:40:17 UTC. A total of 6 CCD images with an exposure of 300 seconds were obtained. Despite the fact that this object is located far from the equator, we checked for the presence of small bodies in this region using the small body database from 14 November 2025. The check was negative. Cross-identification results indicated the same galaxy without any transient events: DSS J120024.56+490254.3, WISEA J120024.53+490254.1, and GALEXASC J120024.49+490252.9. We analyzed our data using our standard pipeline and with STDWeb/STDPipe (Karpov, 2025). We present stacked results after galaxy soustraction. MJD | DATE-OBS | MAG |M_ERR|U.L.|FILTER| Telescope| MAG system -------------------------------------------------------------------------------------- 60994.00920139 | 2025-11-15 00:29 | 21.54|0.1|22.10|R|UBAI/AZT-22|Vega, Gaia DR3 Which has an equivalent using PS1 of 21.64+/- 0.1 in sdssr using PS1 (color term 0.13). More observations are planned. GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/). Maidanak astronomical observatory (MAO) is an observational facility of the Ulugh Beg Astronomical Institute (UBAI), Uzbekistan Academy of Sciences (http://maidanak.uz/). View this GCN Circular online at https://gcn.nasa.gov/circulars/42698. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40761] GRB 251115A: Tiled Swift observations
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42697 SUBJECT: GRB 251115A: Tiled Swift observations DATE: 25/11/15 13:11:54 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/LAT GRB 251115A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/xrt_products/TILED_GRB00140 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/LAT event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42697. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40760] GRB 251115A: Fermi-LAT detection
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42696 SUBJECT: GRB 251115A: Fermi-LAT detection DATE: 25/11/15 12:51:17 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> E. Bissaldi (Politecnico and INFN Bari), A. Holzmann Airasca (UniTrento and INFN Bari), R. Gupta (NASA GSFC), T. Nymark (KTH), F. Longo (University and INFN, Trieste) and S. Lopez (CNRS / IN2P3) report on behalf of the Fermi-LAT Collaboration: On November 15, 2025, Fermi-LAT detected high-energy emission from GRB 251115A, which was also detected by Fermi-GBM (trigger 784869607 / 251115139, GCN 42692) and Global MASTER (GCN 42694). The best LAT on-ground location is found to be: RA, Dec = 330.18, -9.18 (J2000) with an error radius of 0.36 deg (90 % containment, statistical error only). This was 80 deg from the LAT boresight at the time of the GBM trigger (T0 = 03:20:02.67 UT). The data from the Fermi-LAT shows a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0 - 600 s after the GBM trigger is (1.04 ± 0.34) E-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.5 ± 0.4. The highest-energy photon is a 1.6 GeV event which is observed ~ 490 seconds after the GBM trigger. A Swift ToO has been approved for this burst. The Fermi-LAT point of contact for this burst is Tanja Kramer Nymark (tanjan(a)kth.se). 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/42696. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40759] GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42695 SUBJECT: GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis DATE: 25/11/15 11:31:15 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Nicolas Dagoneau (CEA), Chen-Wei Wang (IHEP), Frédéric Piron (LUPM), Jean-Luc Atteia (IRAP) Using the event-by-event data downloaded through the X-band ground station, we report the preliminary ECLAIRs-GRM joint analysis of GRB 251013C (SVOM burst-id sb2525101311, GCN 42222) detected at T0 = 2025-10-13T17:39:42, which was also detected Fermi/GBM (GCN 42259). The refined analysis for ECLAIRs only was reported in GCN 42292. T90s are given in the table below for both ECLAIRs and GRM. | Instrument | Energy Range | T90 (s) | |-----------------|------------------|-----------------| | ECLAIRs | 4–120 keV | 19 (-2 / +5) s | | GRM | 50–300 keV | 13 (-1 / +4) s | The ECLAIRs-GRM joint time-averaged spectrum (T0-0.83 s to T0+17.70 s) in the 8-5000 keV energy range is best fitted by a power-law model with a photon index of 1.55 -0.03/+0.02. With this model, the total 10-1000 keV fluence is (4.58 +/- 0.18)e-06 erg/cm^2. From the likelihood profile of Epeak obtained by iteratively fitting a cutoff power-law model with a frozen Epeak parameter, we derived a 95% confidence level lower limit of approximately 480 keV, which is consistent with the value measured by Fermi (GCN 42259). With a redshift of z = 0.572 (GCN 42227), the burst isotropic energy Eiso (from 1 keV to 10 MeV in its rest frame) is 5.6e51 erg, which makes this GRB consistent with type I GRBs in the 'Amati' relation diagram (Amati et al. 2002). All the quoted errors are at the 68% confidence level. The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. The SVOM/ECLAIRs-GRM point of contact for this burst is: Nicolas Dagoneau (nicolas.dagoneau AT cea.fr). View this GCN Circular online at https://gcn.nasa.gov/circulars/42695. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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