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[vsnet-grb-info 40390] GRB 251014D: Swift-BAT refined analysis
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42315 SUBJECT: GRB 251014D: Swift-BAT refined analysis DATE: 25/10/16 23:04:28 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta(a)nasa.gov> D. M. Palmer (LANL), S. D. Barthelmy (GSFC), R. Gupta (GSFC), N. J. Klingler (GSFC/UMBC/CRESSTII) H. A. Krimm (NSF), S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GSFC), T. Parsotan (GSFC), D. Sadaula (GSFC/UMBC), T. Sakamoto (AGU) (i.e. the Swift-BAT team): Using the data set from T-239 to T+963 sec from the recent telemetry downlink, we report further analysis of BAT GRB 251014D (trigger #1404126) (Klingler, et al., GCN Circ. 42274). The BAT ground-calculated position is RA, Dec = 323.933, -41.873 deg which is RA(J2000) = 21h 35m 43.9s Dec(J2000) = -41d 52' 23.0" with an uncertainty of 2.7 arcmin, (radius, sys+stat, 90% containment). The partial coding was 49%. The mask-weighted BAT light curve shows a main emission followed by weaker emission. T90 (15-350 keV) is 286.98 +- 70.09 sec (estimated error including systematics). The time-averaged spectrum from T+0.39 to T+310.10 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.74 +- 0.38. The fluence in the 15-150 keV band is 1.0 +- 0.2 x 10^-06 erg/cm2. The 1-sec peak photon flux measured from T+5.18 sec in the 15-150 keV band is 0.5 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at https://swift.gsfc.nasa.gov/results/batgrbcat/BAT_refined_circular/1404126 View this GCN Circular online at https://gcn.nasa.gov/circulars/42315. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40389] GRB 251016A: BOOTES-6/DPRT optical upper limit
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42314 SUBJECT: GRB 251016A: BOOTES-6/DPRT optical upper limit DATE: 25/10/16 21:13:12 GMT FROM: I. Perez-Garcia at Institute of Astrophysics of Andalusia <ipg(a)iaa.es> I. Perez-Garcia, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S.-Y. Wu, S. Guziy and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), M. Gritsevich (Univ. of Helsinki), M. Jelinek (ASU-CAS), A. Kumar (ARIES) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report: Following the detection of GRB 251016A by Fermi/GBM (Smith et al., GCN 42309) and SVOM/ECLAIRs (Basa et al., GCN 42308), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) responded to this event starting on Oct 16, 17:35 UT (~ 2.6 h after trigger) with 60s images. No new source is detected within the Swift/XRT X-ray afterglow Source 1 position (Evans et al., GCN 42311) up to magnitude 17.14 using Gaia DR3 Gmag magnitude as reference on our first image. Further images were gathered and using ATLAS REFCAT2 as reference (Tonry et al. 2018) we get an upper limit of: | UT mid exposure | Mag limit | Filter | Exp time (sec) | | ------------------- | --------- | ------ | -------------- | | 2025-10-16 18:05:07 | 19.3 | clear | 60x7 | | 2025-10-16 18:37:07 | 17.6 | Z | 60x4 | | 2025-10-16 18:43:02 | 19.1 | g | 60x4 | | 2025-10-16 19:05:30 | 18.7 | r | 60x3 | | 2025-10-16 19:10:38 | 18.3 | i | 60x4 | We thank the staff at Boyden Observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/42314. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40388] GRB 251016A: Glowbug gamma-ray detection of a short burst
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42313 SUBJECT: GRB 251016A: Glowbug gamma-ray detection of a short burst DATE: 25/10/16 21:06:59 GMT FROM: richard.s.woolf.civ(a)us.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 251016A, which was also detected by SVOM/ECLAIRs (GCN 42308), Fermi/GBM (GCN 42309), and CALET (Trigger 1444661491). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-10-16 14:59:18.560 with a duration of 0.64 s and a total significance of about 76 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/42313. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40387] GRB 251013C: VLA detection
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42312 SUBJECT: GRB 251013C: VLA detection DATE: 25/10/16 20:08:06 GMT FROM: collinchristy(a)arizona.edu C. Christy (University of Arizona), T. Laskar (University of Utah), N. Franz (University of Arizona), K. D. Alexander (University of Arizona), E. Berger (Harvard University), R. Chornock (UC Berkeley), H. J. van Eerten (University of Bath), G. Farley (U. Utah), W. Fong (Northwestern University), R. Gill (UNAM), J. Granot (Open University), R. Margutti (UC Berkeley), and P. Schady (University of Bath) report: We observed GRB 251013C (Fermi GBM team, GCN 42221; Rakotondrainibe et al., GCN 42222) with the Karl G. Jansky Very Large Array (VLA) at multiple frequencies beginning on 2025 October 15 at 02:15 UT (1.36 days after the burst). In our preliminary analysis, we detect the radio counterpart (Laskar et al., GCN 42243; Rhodes et al., GCN 42294) at 10 GHz with a flux density of 0.111 +/- 0.012 mJy at the position: RA (J2000) = 23:03:20.56 +/- 0.03” Dec (J2000) = -0:12:37.22 +/- 0.03” This is consistent with the X-ray position (Rakotondrainibe et al., GCN 42222; Evans et al., GCN 42232), optical position (Palmerio et al., GCN 42223; Masi et al., GCN 42228), and radio position (Laskar et al., GCN 42243; Rhodes et al., GCN 42294). Further observations are planned. We thank the VLA staff for scheduling and executing these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42312. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40386] sb25101602: Swift-XRT counterpart detection
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42311 SUBJECT: sb25101602: Swift-XRT counterpart detection DATE: 25/10/16 20:00:35 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P.A. Evans (U. Leicester), J.A. Kennea (PSU), E. Ambrosi (INAF-IASFPA) , A.P. Beardmore (U. Leicester), M.G. Bernardini (INAF-OAB), R. Brivio (INAF-OAB), D.N. Burrows (PSU), S. Campana (INAF-OAB), M. Capalbi (INAF-OAR), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), V. D'Elia (SSDC & INAF-OAR), S. Dichiara (PSU), M. Ferro (INAF-OAB), A. Melandri (INAF-OAR), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), M. Perri (SSDC & INAF-OAR), C. Salvaggio (INAF-OAB), T. Sbarrato (INAF-OAB), B. Sbarufatti (INAF-OAB), M.A. Williams (PSU) report on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the SVOM/ECLAIRs-detected GRB251016A (sb25101602), collecting 749 s of Photon Counting (PC) mode data between T0+6.6 ks and T0+7.4 ks after the trigger. A likely counterpart has been found. The details of this source are: Source 1 (SWIFT J174512.5-393337): ================================== RA (J2000.0): 266.3024 = 17 45 12.58 Dec (J2000.0): -39.5606 = -39 33 38.2 Error: 4.6 (arcsec, radius, 90% confidence). Detect flag: GOOD Distance: 4.5 arcmin from the SVOM/ECLAIRs position. Mean rate: 0.057 +/- 0.011 ct s^-1 Mean flux: (3.41 +/- 0.64)e-12 erg cm^-2 s^-1 Peak rate: 0.072 +/- 0.019 ct s^-1 Peak flux: (4.4 +/- 1.1)e-12 erg cm^-2 s^-1 ECF: 6.02e-11 erg cm^-2 ct^-1 assuming NH=7.85e+21 cm^-2, gamma=1.55 determined from a spectral fit. XMM UL: 6.5e-13 erg cm^-2 s^-1, (0.3-10 keV) so the source is 3.2-sigma above this 3-sigma upper limit. The source may be fading, at the 1.1-sigma level. There are 2 2MASS objects within the source's 3-sigma error radius. We have detected a total of 9 sources. These have been automatically classified as follows: * 1 likely counterpart * 0 candidate counterparts * 8 uncatalogued X-ray sources * 0 known X-ray sources Uncatalogued X-ray sources -------------------------- Source 2 (SWIFT J174439.5-394550): ================================== RA (J2000.0): 266.1646 = 17 44 39.50 Dec (J2000.0): -39.7642 = -39 45 51.1 Error: 6.1 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 11.4 arcmin from the SVOM/ECLAIRs position. Mean rate: 0.0300 [+0.0096, -0.0079] ct s^-1 Mean flux: (1.29 [+0.41, -0.34])e-12 erg cm^-2 s^-1 Peak rate: 0.0300 [+0.0096, -0.0079] ct s^-1 Peak flux: (1.29 [+0.41, -0.34])e-12 erg cm^-2 s^-1 XMM UL: 7.9e-13 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There are 5 2MASS objects within the source's 3-sigma error radius. Source 3 (SWIFT J174431.8-393913): ================================== RA (J2000.0): 266.1326 = 17 44 31.82 Dec (J2000.0): -39.6537 = -39 39 13.3 Error: 5.9 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 5.7 arcmin from the SVOM/ECLAIRs position. Mean rate: (-1.0 +/- -1.0)e0 ct s^-1 Mean flux: (-4.3 +/- -4.3)e-11 erg cm^-2 s^-1 Peak rate: 0.0123 [+0.0069, -0.0053] ct s^-1 Peak flux: (5.3 [+2.9, -2.3])e-13 erg cm^-2 s^-1 XMM UL: 1.3e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There are 5 2MASS objects within the source's 3-sigma error radius. Source 4 (SWIFT J174456.1-392739): ================================== RA (J2000.0): 266.2340 = 17 44 56.16 Dec (J2000.0): -39.4609 = -39 27 39.2 Error: 14.0 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 7.1 arcmin from the SVOM/ECLAIRs position. Mean rate: (-1.0 +/- -1.0)e0 ct s^-1 Mean flux: (-3.5 +/- -3.5)e-9 erg cm^-2 s^-1 Peak rate: (6.3 [+5.6, -4.0])e-3 ct s^-1 Peak flux: (2.2 [+1.9, -1.4])e-11 erg cm^-2 s^-1 ECF: 3.48e-09 erg cm^-2 ct^-1 assuming NH=3.52e+22 cm^-2, gamma=5.05 determined from a spectral fit. XMM UL: 1.0e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is 1.3-sigma above this 3-sigma upper limit. There is no evidence for fading. There are 34 2MASS objects within the source's 3-sigma error radius. Source 5 (SWIFT J174354.6-392827): ================================== RA (J2000.0): 265.9777 = 17 43 54.65 Dec (J2000.0): -39.4743 = -39 28 27.5 Error: 9.8 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 12.2 arcmin from the SVOM/ECLAIRs position. Mean rate: 0.0128 [+0.0066, -0.0050] ct s^-1 Mean flux: (5.5 [+2.8, -2.1])e-13 erg cm^-2 s^-1 Peak rate: 0.0128 [+0.0066, -0.0050] ct s^-1 Peak flux: (5.5 [+2.8, -2.1])e-13 erg cm^-2 s^-1 XMM UL: 7.2e-13 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There are 22 2MASS objects within the source's 3-sigma error radius. Source 6 (SWIFT J174500.5-394402): ================================== RA (J2000.0): 266.2523 = 17 45 00.55 Dec (J2000.0): -39.7341 = -39 44 02.8 Error: 11.1 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 9.7 arcmin from the SVOM/ECLAIRs position. Mean rate: 0.0156 [+0.0070, -0.0055] ct s^-1 Mean flux: (6.7 [+3.0, -2.4])e-13 erg cm^-2 s^-1 Peak rate: 0.0156 [+0.0070, -0.0055] ct s^-1 Peak flux: (6.7 [+3.0, -2.4])e-13 erg cm^-2 s^-1 XMM UL: 1.3e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There are 18 2MASS objects within the source's 3-sigma error radius. Source 7 (SWIFT J174411.2-392428): ================================== RA (J2000.0): 266.0470 = 17 44 11.28 Dec (J2000.0): -39.4079 = -39 24 28.4 Error: 13.9 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 12.5 arcmin from the SVOM/ECLAIRs position. Mean rate: 0.0167 [+0.0073, -0.0057] ct s^-1 Mean flux: (7.2 [+3.2, -2.4])e-13 erg cm^-2 s^-1 Peak rate: 0.0167 [+0.0073, -0.0057] ct s^-1 Peak flux: (7.2 [+3.2, -2.4])e-13 erg cm^-2 s^-1 XMM UL: 1.1e-12 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. A SIMBAD object `OGLE BLG-DSCT-13120' is 43.9" away. There are 33 2MASS objects within the source's 3-sigma error radius. Source 8 (SWIFT J174427.1-393500): ================================== RA (J2000.0): 266.1131 = 17 44 27.14 Dec (J2000.0): -39.5835 = -39 35 00.6 Error: 11.9 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 4.3 arcmin from the SVOM/ECLAIRs position. Mean rate: (-1.0 +/- -1.0)e0 ct s^-1 Mean flux: (-4.3 +/- -4.3)e-11 erg cm^-2 s^-1 Peak rate: (8.7 [+6.1, -4.5])e-3 ct s^-1 Peak flux: (3.7 [+2.6, -1.9])e-13 erg cm^-2 s^-1 XMM UL: 6.6e-13 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There are 28 2MASS objects within the source's 3-sigma error radius. Source 9 (SWIFT J174502.9-392734): ================================== RA (J2000.0): 266.2622 = 17 45 02.93 Dec (J2000.0): -39.4596 = -39 27 34.6 Error: 8.8 (arcsec, radius, 90% confidence). Detect flag: POOR Distance: 7.5 arcmin from the SVOM/ECLAIRs position. Mean rate: (-1.0 +/- -1.0)e0 ct s^-1 Mean flux: (-4.3 +/- -4.3)e-11 erg cm^-2 s^-1 Peak rate: (8.9 [+6.4, -4.7])e-3 ct s^-1 Peak flux: (3.8 [+2.7, -2.0])e-13 erg cm^-2 s^-1 XMM UL: 7.1e-13 erg cm^-2 s^-1, (0.3-10 keV) so the source is not above this 3-sigma upper limit. There is no evidence for fading. There are 11 2MASS objects within the source's 3-sigma error radius. All fluxes are 0.3-10 keV, observed. For all flux conversions and comparisons with catalogues and upper limits from other missions, we assumed a power-law spectrum with NH=3x10^20 cm^-2 and photon index (Gamma)=1.7 unless otherwise stated. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/SVOM/SVOM_FIELD00042. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42311. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40385] Fermi GRB 251016A: Global MASTER-Net observations report
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42310 SUBJECT: Fermi GRB 251016A: Global MASTER-Net observations report DATE: 25/10/16 19:00:45 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 251016A ( Fermi GBM team, GCN 42309) errorbox 9753 sec after notice time and 9784 sec after trigger time at 2025-10-16 17:42:24 UT, with upper limit up to 16.8 mag. Observations started at twilight. The observations began at zenith distance = 38 deg. The sun altitude is -11.4 deg. The galactic latitude b = -12 deg., longitude l = 344 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3016116 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 9814 | 2025-10-16 17:42:24 | MASTER-SAAO | (17h 41m 59.48s , -48d 04m 09.1s) | C | 60 | 14.4 | 9814 | 2025-10-16 17:42:24 | MASTER-SAAO | (17h 44m 44.95s , -48d 19m 26.1s) | C | 60 | 16.5 | 9909 | 2025-10-16 17:43:58 | MASTER-SAAO | (17h 39m 01.22s , -50d 11m 14.5s) | C | 60 | 16.8 | 9909 | 2025-10-16 17:43:58 | MASTER-SAAO | (17h 36m 07.40s , -49d 55m 40.2s) | C | 60 | 15.2 | 10004 | 2025-10-16 17:45:33 | MASTER-SAAO | (17h 48m 32.79s , -46d 10m 37.6s) | C | 60 | 14.6 | 10004 | 2025-10-16 17:45:33 | MASTER-SAAO | (17h 51m 12.71s , -46d 25m 54.6s) | C | 60 | 16.6 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42310. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40384] GRB 251016A: Fermi GBM Final Localization
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42309 SUBJECT: GRB 251016A: Fermi GBM Final Localization DATE: 25/10/16 15:46:56 GMT FROM: Jacob Smith at Fermi-GBM Team <jrs0118(a)uah.edu> The Fermi GBM team reports the detection of a likely SHORT GRB "At 14:59:19.76 UT on 16 October 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251016A (trigger 782319564/251016625). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 268.93, Dec = -48.82 (J2000 degrees, equivalent to J2000 17h 55m, -48d 49'), with a statistical uncertainty of 3.55 degrees. The angle from the Fermi LAT boresight is 33 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251016625/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251016625/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251016625/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/42309. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40383] GRB 251016A: SVOM detection of a short burst
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42308 SUBJECT: GRB 251016A: SVOM detection of a short burst DATE: 25/10/16 15:30:00 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> S. Basa, S. Boissier (LAM), O. Godet, S. Guillot (IRAP), D. Turpin (CEA) At 2025-10-16T14:59:20 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 251016A (SVOM burst-id sb25101602). 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 5 alerts. CRT provided the alert with the best signal-to-noise-ratio in the image (SNR) of 8.16 in the [8-120] keV energy band over a time window of 0.60 seconds starting at 2025-10-16T14:59:19. The localization of the best alert is R.A., Dec. 266.207, -39.577 degrees: R.A. (J2000) = 17h44m49.58s Dec. (J2000) = -39d34m35.95s with a 90% confidence level (C.L.) radius of 9.64 arcmin (including systematic error of 2 arcmin added in quadrature). The SVOM/ECLAIRs light curve showed a single and narrow peak. This burst also triggered SVOM/GRM at 2025-10-16T14:59:19 on a timescale of 0.10 seconds with an SNR of 37.30. This burst seems to have been detected by Fermi, but with a declination of about 10 degrees offset. The satellite did not slew due to Sun constraint. 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 Stephane Basa: stephane.basa(a)lam.fr. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/42308. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40382] GRB 251014A: Swift-XRT observations
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42307 SUBJECT: GRB 251014A: Swift-XRT observations DATE: 25/10/16 13:51:56 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), S. Lanava (PSU), J.P. Osborne (U. Leicester) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 6.2 ks of Photon Counting (PC) mode XRT data for GRB 251014A, collected between T0+101.1 ks and T0+174.7 ks. Three uncatalogued X-ray sources have been detected within the estimated 3-sigma Swift-BAT error region (296 arcsec), however none of them is above the RASS limit or shows definitive signs of fading. Therefore, at the present time we cannot identify which, if any, is the afterglow. Details of these sources are given below: Source 5: RA (J2000.0): 111.7316 = 07h 26m 55.58s Dec (J2000.0): +6.4150 = +06d 24' 53.9" Error: 6.7 arcsec (radius, 90% conf.) Count-rate: (2.33 [+0.88, -0.72])e-3 ct s^-1 Distance: 1 arcsec from Swift-BAT position. Flux: (1.11 [+0.42, -0.34])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 8: RA (J2000.0): 111.6918 = 07h 26m 46.04s Dec (J2000.0): +6.4252 = +06d 25' 30.7" Error: 6.1 arcsec (radius, 90% conf.) Count-rate: (2.25 [+0.88, -0.72])e-3 ct s^-1 Distance: 148 arcsec from Swift-BAT position. Flux: (7.1 [+2.8, -2.3])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) Source 9: RA (J2000.0): 111.7868 = 07h 27m 08.82s Dec (J2000.0): +6.3731 = +06d 22' 23.3" Error: 5.6 arcsec (radius, 90% conf.) Count-rate: (1.42 [+0.73, -0.56])e-3 ct s^-1 Distance: 247 arcsec from Swift-BAT position. Flux: (4.8 [+2.5, -1.9])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV) Seven uncatalogued sources were also detected too far from the GRB position to be likely afterglow candidates. The results of the XRT-team automatic analysis of the XRT observations, including a position-specific upper limit calculator, are available at https://www.swift.ac.uk/ToO_GRBs/01403878. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42307. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40381] LIGO/Virgo/KAGRA S251014cn: Updated Sky localization
by GCN Circulars 16 Oct '25

16 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42306 SUBJECT: LIGO/Virgo/KAGRA S251014cn: Updated Sky localization DATE: 25/10/16 07:51:43 GMT FROM: Nihar.Gupte(a)aei.mpg.de The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) data around the time of the compact binary merger (CBC) candidate S251014cn (GCN Circular 42255. Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN and SCiMMA notices, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S251014cn For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 172 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 607 +/- 164 Mpc (a posteriori mean +/- standard deviation). For further information about analysis methodology and the contents of this alert, refer to the LIGO/Virgo/KAGRA Public Alerts User Guide https://emfollow.docs.ligo.org/. [1] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 View this GCN Circular online at https://gcn.nasa.gov/circulars/42306. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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