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

[vsnet-grb-info 37316] GRB250101A: Radio upper limits from GMRT observations
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39307 SUBJECT: GRB250101A: Radio upper limits from GMRT observations DATE: 25/02/13 03:05:42 GMT FROM: Arvind Balasubramanian <arvind6895(a)gmail.com> A. Balasubramanian (IIA), A.P. Saikia (IITB), V. Swain (IITB), G.C. Anupama (IIA), S. Barway (IIA), V. Bhalerao (IITB) report We observed the field of the gamma ray burst GRB250101A (Page et al. GCN 38752, Li et al. GCN 38753, Mohan et al. GCN 38754, Zhu et al. GCN 38755, Budnev et al. GCN 38756, Wu et al. GCN 38758, Odeh et al. GCN 38763) with the Giant Metrewave Radio Telescope (GMRT) under the DDT (PI: A. Balasubramanian, ddtC419) on 8th February 2025 in band 5 (1.3 GHz) for about 2 hours starting at 13:30 hours UTC. We do not detect any significant radio emission at the position of the optical counterpart (Li et al. GCN 38753). We used 3C48 for the flux calibration and J0238+166 for complex gain and phase calibration. The CASA calibration and imagining CAPTURE-CASA6 pipline was used for data calibration and imaging. We compute a 3-sigma upper limit of ~150 uJy at 1.3 GHz. We thank the GMRT Time Allocation Committee for accepting our DDT proposal and GMRT staff that made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/39307. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37315] EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39306 SUBJECT: EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit DATE: 25/02/12 23:03:14 GMT FROM: Daniele B. Malesani at IMAPP / Radboud University <d.malesani(a)astro.ru.nl> D. B. Malesani (DAWN/NBI and Radboud Univ.), A. Martin-Carrillo (UCD), P. G. Jonker (Radboud), L. Galbany (ICE-CSIC), K. Phan (ICE-CSIC), B. Hauptmann (NOT and DTU Space) report on behalf of a larger collaboration: We observed the field of the EP trigger 10202399251, which occurred on 2025 Feb 12 (possibly named EP250212a), using the Nordic Optical Telescope (NOT) equipped with the NOTCam near-infrared imager. Observations were conducted in the J band, for a total of 18x60 s exposures, with a mid time of 2025 Feb 12.837 UT (12.3 hr after the EP trigger). Within the error circle of the EP/FXT X-ray counterpart, we detect no new sources down to a limiting magnitude of J = 20.9 (Vega), calibrated against nearby stars from the 2MASS catalog. View this GCN Circular online at https://gcn.nasa.gov/circulars/39306. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37314] EP250207B: GTC Near-Infrared Observations
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39305 SUBJECT: EP250207B: GTC Near-Infrared Observations DATE: 25/02/12 22:09:01 GMT FROM: Rosa L. Becerra at Tor Vergata, Roma <rosa.becerra(a)roma2.infn.it> Yu-Han Yang (U Rome), Rosa L. Becerra (U Rome), Alan M. Watson (UNAM), Eleonora Troja (U Rome), Simone Dichiara (PSU) and Lei Hu (CMU) report on behalf of a larger team: We observed the field of EP250207B detected by EP/WXT (Zhou et al., GCN 39266) with the OSIRIS instrument on the GTC telescope starting at 2025-02-12 05:22 UTC (T+4.31 days after the trigger). We obtained a total integration of 480 seconds (8x60 s) in z with a seeing of about 1.2 arcsec. We performed image subtraction on the stacked images using reference images from the Legacy Survey DR10 (Dey et al. 2019). In our preliminary analysis, we detect artifacts of the image subtraction at the position of the Liverpool Telescope candidate (Eyles-Ferris et al. GCN 39281). However, we do not detect a significant source at this position. In both our data and the Legacy Survey images, we do not detect a source at the right ascension and declination given by Fraser et al. (GCN 39287) and consider that perhaps there is a small error in this stated position. However, we do detect two sources close to their reported position. Both are visible in the Legacy Survey DR10 catalog (Dey et al. 2019) with a photo-z~0.9, and we do not detect any evidence of brightening. Finally, at the position of the NOT candidate reported by Liu et al.,(GCN 39300), we do not detect any source down to a limit of 3-sigma z > 23.8 AB. This value is not corrected for Galactic extinction. Further observations are planned. We thank the staff of the GTC, especially Gianluca Lombardi and Antonio Cabrera, for their help and rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39305. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37313] Fermi GRB 250212A: Global MASTER-Net observations report
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39304 SUBJECT: Fermi GRB 250212A: Global MASTER-Net observations report DATE: 25/02/12 21:16:20 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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 (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB 250212A ( Fermi GBM team, GCN 39294) errorbox 69293 sec after notice time and 69339 sec after trigger time at 2025-02-12 20:05:33 UT, with upper limit up to 15.8 mag. The observations began at zenith distance = 46 deg. The sun altitude is -40.0 deg. The galactic latitude b = 21 deg., longitude l = 82 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2775797 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 69341 | 2025-02-12 20:05:33 | MASTER-Tunka | (17h 48m 16.26s , +54d 08m 37.4s) | C | 1 | 15.6 | 69443 | 2025-02-12 20:07:16 | MASTER-Tunka | (17h 47m 16.27s , +56d 03m 20.7s) | C | 1 | 15.8 | 69694 | 2025-02-12 20:11:27 | MASTER-Tunka | (18h 25m 56.36s , +61d 43m 25.6s) | C | 1 | 15.3 | 69939 | 2025-02-12 20:15:31 | MASTER-Tunka | (17h 48m 15.51s , +54d 10m 22.0s) | C | 1 | 15.3 | 70145 | 2025-02-12 20:18:58 | MASTER-Tunka | (17h 47m 19.31s , +56d 03m 48.4s) | C | 1 | 15.6 | 70398 | 2025-02-12 20:23:10 | MASTER-Tunka | (18h 25m 59.43s , +61d 42m 08.6s) | C | 1 | 15.4 | 70557 | 2025-02-12 20:25:50 | MASTER-Tunka | (17h 48m 21.23s , +54d 09m 57.1s) | C | 1 | 15.6 | 70753 | 2025-02-12 20:29:06 | MASTER-Tunka | (17h 47m 14.86s , +56d 04m 17.1s) | C | 1 | 15.2 | 71065 | 2025-02-12 20:34:18 | MASTER-Tunka | (18h 26m 02.66s , +61d 42m 45.1s) | C | 1 | 15.3 | 71229 | 2025-02-12 20:37:02 | MASTER-Tunka | (17h 48m 21.82s , +54d 10m 29.4s) | C | 1 | 15.4 | 71244 | 2025-02-12 20:37:16 | MASTER-Tunka | (18h 15m 35.48s , +54d 07m 19.0s) | C | 1 | 15.2 | 71258 | 2025-02-12 20:37:30 | MASTER-Tunka | (18h 16m 07.40s , +56d 01m 18.4s) | C | 1 | 15.2 | 71268 | 2025-02-12 20:37:41 | MASTER-Tunka | (17h 50m 20.80s , +52d 17m 18.1s) | C | 1 | 15.4 | 71278 | 2025-02-12 20:37:51 | MASTER-Tunka | (17h 53m 18.75s , +50d 21m 26.9s) | C | 1 | 15.4 | 71291 | 2025-02-12 20:38:04 | MASTER-Tunka | (18h 17m 53.75s , +57d 56m 40.2s) | C | 1 | 14.6 | 71307 | 2025-02-12 20:38:19 | MASTER-Tunka | (18h 21m 02.65s , +59d 49m 51.2s) | C | 1 | 14.9 | 71400 | 2025-02-12 20:39:52 | MASTER-Tunka | (17h 47m 19.76s , +56d 03m 54.7s) | C | 1 | 15.1 | 71741 | 2025-02-12 20:45:34 | MASTER-Tunka | (18h 26m 03.43s , +61d 43m 48.0s) | C | 1 | 13.7 | 72033 | 2025-02-12 20:50:25 | MASTER-Tunka | (17h 48m 21.88s , +54d 11m 51.0s) | C | 1 | 12.4 | 72044 | 2025-02-12 20:50:36 | MASTER-Tunka | (18h 15m 41.15s , +54d 07m 56.4s) | C | 1 | 12.3 | 72053 | 2025-02-12 20:50:46 | MASTER-Tunka | (18h 16m 10.34s , +56d 03m 20.5s) | C | 1 | 12.1 | 72065 | 2025-02-12 20:50:57 | MASTER-Tunka | (17h 50m 19.79s , +52d 17m 00.3s) | C | 1 | 12.2 | 72075 | 2025-02-12 20:51:07 | MASTER-Tunka | (17h 53m 17.59s , +50d 23m 48.8s) | C | 1 | 12.2 | 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/39304. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37312] LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39303 SUBJECT: LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber DATE: 25/02/12 19:45:10 GMT FROM: David Coulter at STScI <dcoulter(a)ucsc.edu> D. A. Coulter (STScI), C. D. Kilpatrick (NU), I. Andreoni (UNC), P. Macias (UCSC), R. J. Foley (UCSC), K. W. Davis (UCSC), V. A. Villar (Harvard) reports on behalf of the Gravity Collective [1, 2]: We followed up the reported optical candidate, AT2025ber ([GCN 39286](https://gcn.nasa.gov/circulars/39286)), associated with S250206dm (LVK Collaboration, [GCN 39175](https://gcn.nasa.gov/circulars/39175)), with the ~0.22 square degree field-of-view near-IR imager NEWFIRM mounted on the Blanco 4-m telescope at CTIO, Chile. Our observations began on 2025-02-12 07:22 UTC (+5 days after trigger) and consisted of 40x80s exposures in H-band. Data were processed using standard procedures in photpipe [3]. We do not detect any emission at the site of AT2025ber in forced aperture photometry, and we derive a limiting magnitude of H=23.0 AB mag (3-sigma) at the site of the reported candidate. Our pointing and limit are available in the [GW Treasure Map](https://treasuremap.space/alerts?graceids=S250206dm) [4]. We thank Sean Points, Alberto Alvarez, and CTIO for their support in obtaining these observations. 1. Kilpatrick, C. D. et al. 2021 2. Coulter, D. A., et al. 2024 3. Rest, A. et al. 2005 4. Wyatt, S. D. et al. 2020 View this GCN Circular online at https://gcn.nasa.gov/circulars/39303. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37311] GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39302 SUBJECT: GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit DATE: 25/02/12 17:38:07 GMT FROM: Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy <giovannicalapai(a)tiscali.it> Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy Member of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani. Report: We imaged the field of GRB 250205A detected by SVOM/ECLAIRs telescope (Saccardi et al. GCN 39154), with the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3. The observations were started at 2025-02-05 23:12 UT (approximately 1.79 hours after burst) stacking a set of unfiltered CCD image. The observations were carried out with clear skies and good visibility conditions. We co-added 183 exposures of 60 sec each. Start T0+ End T0+ CR lim 1.79 hour 5.88 hour 20.2 We did not found any optical counterpart in the error box of the XRTcandidate. Kennea et al. GCN 39161 Magnitudes were estimated with the PanSTARRS cat. and are not corrected for galactic dust extinction. Our observations are consistent with other already reported Gompertz et al. (GCN 39156), Schneider et al. (GCN 39157), Gompertz et al. (GCN 39158), Palmerio et al. (GCN 39159), A. de Ugarte Postigo et al. (GCN 39160), Watson et al. (GCN 39162), Breeveld et al. (GCN 39168), Busmann et al. (GCN 39169), Ferro et al. (GCN 39170). The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/39302. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37310] Fermi trigger No 760945500: Global MASTER-Net observations report
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39301 SUBJECT: Fermi trigger No 760945500: Global MASTER-Net observations report DATE: 25/02/12 17:30:30 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, N.Tiurina, P.Balanutsa, , D.Vlasenko, I.Panchenko, A.Kuznetsov, G.Antipov, A.Sankovich, A.Sosnovskij, Yu.Tselik, M.Gulyaev, 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. 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 (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in Russia (Applied Physics Institute, Irkutsk State University) started inspect of the Fermi GRB250211.24 (trigger No 760945500,05h 37m 07.20s , +73d 12m 00.0s, R=1.08) errorbox 1 days 30989 sec after notice time and 1 days 31021 sec after trigger time at 2025-02-12 14:21:57 UT, with upper limit up to 17.5 mag. The observations began at zenith distance = 24 deg. The sun altitude is -38.1 deg. The galactic latitude b = 21 deg., longitude l = 140 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2775055 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 117435 | 2025-02-12 14:21:57 | MASTER-Tunka | (05h 31m 57.85s , +73d 40m 33.8s) | C | 25 | 16.5 | 117534 | 2025-02-12 14:23:39 | MASTER-Tunka | (05h 01m 45.40s , +71d 46m 33.1s) | C | 20 | 16.3 | 118179 | 2025-02-12 14:34:29 | MASTER-Tunka | (05h 01m 36.73s , +71d 48m 31.6s) | C | 10 | 16.1 | 118962 | 2025-02-12 14:47:29 | MASTER-Tunka | (05h 15m 12.08s , +75d 35m 19.0s) | C | 15 | 17.5 | 119048 | 2025-02-12 14:48:53 | MASTER-Tunka | (05h 45m 25.39s , +71d 49m 25.5s) | C | 20 | 15.5 | 119984 | 2025-02-12 15:04:31 | MASTER-Tunka | (05h 31m 28.65s , +73d 42m 32.1s) | C | 15 | 16.8 | 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/39301. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37309] EP250207b: NOT optical counterpart candidate
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39300 SUBJECT: EP250207b: NOT optical counterpart candidate DATE: 25/02/12 15:11:09 GMT FROM: Dong Xu at NAOC/CAS <dxu(a)nao.cas.cn> X. Liu, J. An, S.Q. Jiang, S.Y. Fu, Z.P. Zhu, D. Xu (NAOC), J.P.U. Fynbo (DAWN/NBI), M. A. Diaz Teodori, R. H. Rasmussen, A. M. Kadela (NOT) report on behalf of a large collaboration: We observed the field of EP250207b detected by EP/WXT (Zhou et al., GCN39266) using the 2.56m Nordic Optical Telescope (NOT) equipped with the ALFOSC camera. A total of 4 x 200 s frames in Sloan r-band were obtained at a mid time of 03:16:13 UT on 2025-02-09, i.e., 1.23 days after the EP trigger time. We performed image subtraction on our stacked image using both PanSTARRS and Legacy Survey images as templates. Within the EP/FXT error circle, an uncatalogued faint source was detected with a magnitude of r ~ 23.7 mag (AB), calibrated against nearby PanSTARRS stars, at coordinates R.A.(J2000) = 11:10:03.21 Dec.(J2000) = -07:52:07.20 with an uncertainty of ~ 1 arcsec. It is about 10 arcsec away from the galaxy WISEA J111002.65-075211.9 noted by Malesani et al. (GCN 39270) and Levan et al. (GCN 39278). The brightness of the galaxy in our image shows no brightening compared to PanSTARRS kron magnitude. In addition, the source reported by Fraser et al. (GCN 39287) is not detected in our stacked image, down to a 5-sigma limiting magnitude of r ~ 23.0 mag (AB). The magnitudes reported above have not been corrected for Galactic extinction. Further observations are planned and deep r-band photometry of the field is encouraged. View this GCN Circular online at https://gcn.nasa.gov/circulars/39300. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37308] GRB 250211A: SVOM trigger sb25021103 is not a GRB
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39299 SUBJECT: GRB 250211A: SVOM trigger sb25021103 is not a GRB DATE: 25/02/12 10:50:31 GMT FROM: F. Fortin at IRAP <ffortin.sci.edu(a)gmail.com> F. Fortin (IRAP), J. Malzac (IRAP), O. Godet (IRAP), M. Brunet (IRAP) report on behalf of the SVOM mission team: The SVOM/ECLAIRs telescope triggered at 2025-02-11T17:50:32 UTC on an uncatalogued source (SVOM trigger sb25021103). After reviewing the ECLAIRs data, we now conclude that sb25021103 is not a GRB but likely an outburst from the Galactic transient LMXB 4U 1604-52. We manually requested a Swift ToO, which was unfortunately requested at an incorrect sky position. Hence, none of the Swift sources from this observation (Evans, GCN 39296) are related to this trigger. We apologize for the inconvenience, and we acknowledge the excellent support from the Swift team for performing the quick ToO. The Space 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. The Burst Advocates (BAs) on shift for this trigger are Francis Fortin (francis.fortin(a)irap.omp.eu) and Julien Malzac (julien.malzac(a)irap.omp.eu). Please contact the BA by email if you require additional information regarding the SVOM follow-up of this event. View this GCN Circular online at https://gcn.nasa.gov/circulars/39299. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 37307] GRB 250211B: A long GRB detected by INTEGRAL
by GCN Circulars 12 Feb '25

12 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39298 SUBJECT: GRB 250211B: A long GRB detected by INTEGRAL DATE: 25/02/12 07:26:35 GMT FROM: Sandro Mereghetti at IASF-Milano/INAF <sandro.mereghetti(a)inaf.it> S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno, E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC, Versoix) and J.Borkowski (CAMK, Torun) report: a gamma ray burst lasting about 60 s has been detected by IBAS in the IBIS/ISGRI data at 21:27:10 UT of 2025 February 11. The refined coordinates (J2000) are: R.A.= 276.3784 deg DEC.= -31.9655 deg with an uncertainty of 2 arcmin (90% c.l.). The burst had a peak flux of about 0.2 ph/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 4e-7 erg/cmq. A plot of the light curve will be posted at http://ibas.iasf-milano.inaf.it/IBAS_Results.html View this GCN Circular online at https://gcn.nasa.gov/circulars/39298. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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vsnet-grb-info February 2025