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

[vsnet-grb-info 40320] GRB 251014A: Fermi GBM Observation
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42249 SUBJECT: GRB 251014A: Fermi GBM Observation DATE: 25/10/14 09:45:29 GMT FROM: Cuán de Barra at UCD <cuan.debarra(a)ucdconnect.ie> C. de Barra (University College Dublin), J. Smith (UAH), C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 00:28:30.34 UT on 14 October 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251014A (trigger 782094515/251014020). which was also detected by Swift BAT (E. Ambrosi et al. 2025, GCN 42238). The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 44 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 1.7 s (50-300 keV). The time-averaged spectrum from T0-0.2 to T0+1.7 s is best fit by a simple power law function with index -1.78 +/- 0.06. The event fluence (10-1000 keV) in this time interval is (6.2 +/- 0.5)E-07 erg/cm^2. The 64-ms peak photon flux measured starting from T0+0.32 s in the 10-1000 keV band is 6 +/- 1 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/42249. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40319] GRB 251013C: J band observations by SYSU 80cm infrared telescope
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42248 SUBJECT: GRB 251013C: J band observations by SYSU 80cm infrared telescope DATE: 25/10/14 07:17:23 GMT FROM: zhanghr33(a)mail2.sysu.edu.cn Hao-Ran Zhang, Chen Chun, Duo-Le Cao, Zhong-Nan Dong, Wei-Sen Huang, Jin-Ji Li, Jia-Qi Lin, Pu Lin, Yan Yu, Hao-Nan Yang, P H Thomas Tam, Rong-Feng Shen, Bin Ma (Sun Yat-sen University) report on behalf of the SYSU 80cm infrared telescope team: We observed the field of GRB 251013C detected by SVOM (N. A. Rakotondrainibe et al., GCN 42222) and Fermi (Fermi GBM Team, GCN 42221), using the Sun Yat-sen University 80cm infrared telescope with 20 s exposures in J band. The calculated position is R.A. = 345.8301 deg, Dec = -0.2207deg J2000, from SVOM observation. Our observations began at 2025-10-13 18:03:42 UTC, 0.41 hours after the SVOM trigger. We clearly detect an infrared counterpart at the position of the optical afterglow (J. T. Palmerio et al., GCN 42223; I. Perez-Garcia et al., GCN 42225; R. Konno et al., GCN 42226; L. A. Martin-Carrillo et al., GCN 42227; Gianluca Masi, GCN 42228; J. T. Palmerio et al., GCN 42229; A. S. Moskvitin et al., GCN 42230; B. P. Gompertz et al., GCN 42231; V.Lipunov et al., GCN 42235; P. Garnavich, GCN 42240; Alan M. Watson et al., GCN 42241; Diego López-Cámara et al., GCN 42242). The earliest detection is confirmed at 2025-10-13 18:03:42UTC (T – T0 = 0.41 h) with J mag: 13.49+/-0.14 (Vega system). Preliminary photometry shows a rise of ~0.4mag at 18:26:00UTC (T – T0 = 0.78 h), followed by a rapid decay. The photometric calibration was performed using nearby stars from the 2MASS catalog. The photometric accuracy is limited due to the cloudy weather. The SYSU 80cm infrared telescope is operated and managed by the Department of Astronomy, Sun Yat-sen University. View this GCN Circular online at https://gcn.nasa.gov/circulars/42248. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40318] GRB 251013C: EP-FXT counterpart detection
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42247 SUBJECT: GRB 251013C: EP-FXT counterpart detection DATE: 25/10/14 05:55:24 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> B.T. Wang (YNAO, CAS), H. Zhou (PMO, CAS), Z.M. Wang (BNU), P.Y. Han (HUST), R.X. Hu (WHU), D.Z. Du (ZJU), and C.C. Jin (NAO, CAS) on behalf of the Einstein Probe (EP) team: EP-FXT performed a follow-up observation of the SVOM/ECLAIRs-detected burst GRB 251013C (SVOM/sb25101311, Rakotondrainibe et al., GCN #42222, also detected by Fermi/GBM GCN #42221) at 2025-10-13T19:39:21 (UTC), about 2.0 hours after the SVOM/ECLAIRs trigger, with an exposure time of 1690 s. One uncatalogued source is detected within the ECLAIRs error circle, and the source is spatially consistent with the counterpart reported in optical and X-ray bands (Palmerio et al. GCN #42223, Perez-Garcia et al., GCN #42225, Konno et al., GCN #42226, Masi et al., GCN #42228, Palmerio et al., GCN #42229, Moskvitin et al., GCN #42230, Gompertz et al., GCN #42231, Evans et al., GCN #42232, Garnavich et al., GCN #42240, Watson et al., GCN #42241, López-Cámara et al., GCN #42242) with redshift at 0.572 (Martin-Carrillo et al., GCN #42227). Preliminary analysis on this source are automatically conducted, and details are listed as follows. Source 1: EPF_J230320.5-001237 RA (J2000): 345.8356 Dec (J2000): -0.2103 Flux: 3.75 x 10^-10 erg/s/cm2 (observed, 0.5-10 keV) Flux_err: 7.89 x 10^-12 erg/s/cm2 (1 sigma) The position uncertainty of the source is about 10 arcsec in radius (90% C.L. statistical and systematic). 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/42247. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40317] GRB 251013C: AstroSat CZTI detection
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42246 SUBJECT: GRB 251013C: AstroSat CZTI detection DATE: 25/10/14 05:53:26 GMT FROM: Anuraag Arya at IIT Bombay <aryaanuraag910(a)gmail.com> A. Arya (IITB), U. Pathak (IITB), A. Goyal (IITB), Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), G. Waratkar (Caltech/IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 251013C which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 42221), and SVOM/ECLAIRs (Rakotondrainibe et. al., GCN Circ. 42222). The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2025-10-13 17:39:42.75 UTC. The measured peak count rate associated with the burst is 87 (+43, -15) counts/s above the background in the combined data of three quadrants (out of four), with a total of 337 (+89, -97) counts. The local mean background count rate was 202 (+3, -3) counts/s. Using cumulative rates, we measure a T90 of 7.3 (+0.7, -1.1) s. We caution that there is a 0.3 s dead time in the CZTI data just after the burst, hence the actual T90 may be slightly longer. The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2025-10-13 17:39:42.33 UTC. The measured peak count rate associated with the burst is 281 (+68, -36) counts/s above the background in the combined data of all quadrants, with a total of 1351 (+229, -274) counts. The local mean background count rate was 1171 (+6, -9) counts/s. We measure a T90 of 6.7 (+0.8, -1.8) s from the cumulative Veto light curve. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb View this GCN Circular online at https://gcn.nasa.gov/circulars/42246. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40316] GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42245 SUBJECT: GRB 251011A: Swift/BAT-GUANO arcminute localization of a burst DATE: 25/10/14 05:15:00 GMT FROM: Jimmy DeLaunay at Penn State <delauj2(a)gmail.com> James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Jamie A. Kennea (PSU), Samuele Ronchini (GSSI), Gayathri Raman (PSU), Tyler Parsotan (GSFC), Maia Williams (Northwestern) report: Swift/BAT did not localize GRB 251011A onboard (T0: 2024-10-11T03:41:40.09 UTC, Fermi GCN 42195, AstroSat CZTI GCN 42199, Insight-HXMT GCN 42210). The Fermi/GBM notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The burst occurred during a Swift slew. The arcmin position of the burst is found with the newly developed pipeline BAT-GLIMPSE: Gamma-ray Localization using Imaging and Mosaic techniques for Pointing and Slew Epochs (Ronchini et. al, in prep). The pipeline makes use of the tools from BatAnalysis (Parsotan et al. 2025). A confident location is found for the burst with SNR of 23.5. The burst is detected in BAT with a duration of ~ 5 seconds. The BAT position is RA, Dec = 4.7878, +45.1894 deg which is RA(J2000) = 00h 19m 09.07s Dec(J2000) = +45d 11’ 21.84″ with an estimated uncertainty of 5 arcmin. This position is consistent with the Ferm/GBM localization (GCN 42195). GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ View this GCN Circular online at https://gcn.nasa.gov/circulars/42245. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40315] GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42244 SUBJECT: GRB 251013D: Swift/BAT-GUANO arcminute localization of a burst DATE: 25/10/14 04:52:39 GMT FROM: Jimmy DeLaunay at Penn State <delauj2(a)gmail.com> James DeLaunay (PSU), Aaron Tohuvavohu (Caltech), Samuele Ronchini (GSSI), Gayathri Raman (PSU), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC), Maia Williams (Northwestern) report: Swift/BAT did not localize GRB 251013D onboard (T0: 2025-10-13T18:17:00.39 UTC, Fermi Trig 782072225). The Fermi notice, distributed in near real-time, triggered the Swift Mission Operations Center operated Gamma-ray Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al. 2020, ApJ, 900, 1). Upon trigger by this notice, GUANO sent a command to the Swift Burst Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from [-50,+150] seconds around the time of the burst. All the requested event mode data was delivered to the ground. The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ, 941, 169), detects the burst in a 16.384 s analysis time bin starting at T0 - 0.0 s with a sqrt(TS) of 27.6. An arcminute localization is found with DeltaLLHOut of 159 and a DeltaLLHPeak of 130. See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and DeltaLLHOut. The BAT position is RA, Dec = 46.901, 8.800 deg which is RA(J2000) = 03h 07m 36.24s Dec(J2000) = 8d 48’ 00.0″ with an estimated uncertainty of 5 arcmin radius. More details about this burst can be found on the trigger report page here: https://guano.swift.psu.edu/trigger_report?id=782072256 XRT and UVOT follow-up has been requested. Results of follow-up observations will be reported in future circulars. GUANO is a fully autonomous, extremely low latency, spacecraft commanding pipeline designed for targeted recovery of BAT event mode data around the times of compelling astrophysical events to enable more sensitive GRB searches. A live reporting of Swift/BAT event data recovered by GUANO can be found at: https://www.swift.psu.edu/guano/ View this GCN Circular online at https://gcn.nasa.gov/circulars/42244. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40314] GRB 251013C: ALMA detection
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42243 SUBJECT: GRB 251013C: ALMA detection DATE: 25/10/14 03:51:49 GMT FROM: Tanmoy Laskar at U of Utah <tanmoylaskar(a)gmail.com> T. Laskar (University of Utah), C. Christy, N. Franz, 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 Atacama Large Millimeter/Submillimeter Array (ALMA) at 97.5 GHz beginning on 2025 October 13 at 23:07 UT (5.5 hours after the burst). Preliminary analysis reveals a mm source with flux density of ~ 0.3 mJy at position: RA (J2000) = 23:03:20.56 Dec (J2000) = -00:12:37.21 with an uncertainty of 0.02" in each coordinate. This is consistent with the X-ray position (Rakotondrainibe et al., GCN 42222; Evans et al., GCN 42232) and optical position (Palmerio et al., GCN 42223; Masi et al., GCN 42228). Further observations are planned. We thank the NAASC staff, P2G, AoD, JAO staff, and the entire ALMA team for their help with these observations." View this GCN Circular online at https://gcn.nasa.gov/circulars/42243. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40313] GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42242 SUBJECT: GRB 251013C: SVOM/COLIBRÍ (FM-GFT) detection of the optical counterpart DATE: 25/10/14 03:33:15 GMT FROM: Diego López-Cámara at Instituto de Ciencias Nucleares, UNAM <diego(a)correo.nucleares.unam.mx> Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Alan M. Watson (UNAM), Camila Angulo (UNAM), Ny Avo Rakotondrainibe (LAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc Atteia (IRAP), Dalya Akl (NYUAD), Sarah Antier (OCA), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU) , Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Francis Fortin (IRAP), Leonardo García-García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Fredd Sánchez Álvarez (UNAM), Benjamin Schneider (LAM), and Antonio de Ugarte Postigo (LAM) report: We imaged the field of the SVOM GRB 251013C (Rakotondrainibe et al., GCN Circ. 42222) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We obtained a 60 seconds exposure in the r filter starting at 2025-10-14 02:18 (8.65 hours after the trigger). The image was analyzed with STDWeb/STDPipe (Karpov 2025). The photometry was calibrated using nearby stars from the PanSTARRS catalog, is in the AB system, and is not corrected for Galactic extinction. We detected the optical counterpart, (Palmerio et al., GCN Circ. 42223; Perez-Garcia et al., GCN Circ. 42225; Konno et al., GCN Circ. 42226; Martin-Carrillo et al., GCN Circ. 42227; Masi et al., GCN Circ. 42228; Palmerio et al., GCN Circ. 42229; Moskvitin et al., GCN Circ. 42230; Gompertz et al., GCN Circ. 42231; Lipunov et al., GCN Circ. 42235; and Garnavich et al., GCN Circ. 42240; Watson et al. GCN Circ. 42241) with a preliminary magnitude of: r = 18.50 +/- 0.03 Compared to the observation reported by Garnevich (GCN Circ. 42240), our observation suggests an abrupt fading between 6.4 and 8.7 hours. Further observations and analysis are ongoing. We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/42242. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40312] GRB 251013C: DDOTI detection of the optical afterglow
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42241 SUBJECT: GRB 251013C: DDOTI detection of the optical afterglow DATE: 25/10/14 03:26:13 GMT FROM: Alan Watson at UNAM <alan(a)astro.unam.mx> Alan M. Watson (UNAM), Camila Angulo Valdez (UNAM), Rosa L. Becerra (U Roma), Nat Butler (ASU), Simone Dichiara (Penn State University), Tsvetelina Dimitrova (ASU), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), Océlotl López (UNAM), Margarita Pereyra (UNAM) and Eleonora Troja (U Roma) report: We observed the field of GRB 251013C detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 42221) and SVOM/ECLAIRS (Rakotondrainibe et al., GCN Circ. 42222) with the DDOTI wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Mártir (http://ddoti.astroscu.unam.mx) from 2025-10-14 02:41 to 03:08 (8.80 to 9.45 hours after the trigger) and obtained a total of 23 minutes of exposure in the w filter. We detect the optical afterglow (Palmerio et al., GCN Circ. 42223; Perez-Garcia et al., GCN Circ. 42225; Konno et al., GCN Circ. 42226; Martin-Carrillo et al., GCN Circ. 42227; Masi et al., GCN Circ. 42228; Palmerio et al., GCN Circ. 42229; Moskvitin et al., GCN Circ. 42230; Gompertz et al., GCN Circ. 42231; Lipunov et al., GCN Circ. 42235; and Garnavich et al., GCN Circ. 42240) with a preliminary magnitude of w = 18.95 +/- 0.04 Our photometry is calibrated against the USNO-B1 and Pan-STARRS PS1 DR2 catalogues and is not corrected for Galactic extinction. Observations are continuing. We thank the staff of the Observatorio Astronómico Nacional at the Sierra de San Pedro Mártir for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/42241. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40311] GRB 20251013C: SLKT optical afterglow photometry
by GCN Circulars 13 Oct '25

13 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42240 SUBJECT: GRB 20251013C: SLKT optical afterglow photometry DATE: 25/10/14 02:43:16 GMT FROM: Peter Garnavich at U of Notre Dame <pgarnavi(a)nd.edu> P. Garnavich (University of Notre Dame) reports: The Sarah L. Krizmanich Telescope (SLKT) obtained unfiltered observations of the SVOM/ECLAIRs source GRB 251013C (Rakotondrainibe et al., GCN 42222). Imaging was centered at 2025 October 14.002 (UT) which was 6.4 hours after the GRB trigger. Exposures totaled 320s and the afterglow was clearly detected. Compared to the nearby star at 23:03:20.64 -00:10:13.8 (2000) with a SDSS magnitude of r=14.40 mag, the afterglow had a brightness of r=17.48+/-0.06 mag. View this GCN Circular online at https://gcn.nasa.gov/circulars/42240. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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