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

[vsnet-grb-info 37326] GRB 250213A: SVOM detection of a burst
by GCN Circulars 14 Feb '25

14 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39317 SUBJECT: GRB 250213A: SVOM detection of a burst DATE: 25/02/14 00:57:43 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Yun Wang (MPO), Wen-Jin Xie (NAOC), J.-L. Atteia (IRAP), N. Dagoneau (CEA), F. Piron (LUPM), Li Zhang (IHEP) report on behalf of the SVOM mission team. At 2025-02-13T23:46:24 UTC (Tb) SVOM/ECLAIRs triggered on the gamma-ray burst GRB 250213A (SVOM burst-id sb25021316). The following trigger information was received on the … [View More]

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[vsnet-grb-info 37325] EP250212a: Global MASTER-Net observations report
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39316 SUBJECT: EP250212a: Global MASTER-Net observations report DATE: 25/02/13 23:54:28 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.… [View More]

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[vsnet-grb-info 37324] GRB 250205A: VIRT Optical Upper Limit
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39315 SUBJECT: GRB 250205A: VIRT Optical Upper Limit DATE: 25/02/13 22:07:44 GMT FROM: Priya Gokuldass at ERAU <gokuldap(a)my.erau.edu> K. Smith (UVI), P. Gokuldass (ERAU), N. Orange (OrangeWave Innovative Science, LLC), B. Gendre (UVI), D. Morris (NASA), T. Lombardi (Eckerd College), F. George (ERAU), D. Smith (UVI), and C. Watson (UVI) report: We observed the field of GRB250205A (Saccardi et al., GCN 39154) with the 0.5m Virgin Islands Robotic … [View More]

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[vsnet-grb-info 37323] GRB 250205A: Leavitt Observatory optical upper limit
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39314 SUBJECT: GRB 250205A: Leavitt Observatory optical upper limit DATE: 25/02/13 21:56:42 GMT FROM: leavittob(a)gmail.com E. Pavoni and L. Moretti (Leavitt Observatory, Manciano, Italy) Members of: GRB/UAI - Gamma Ray Burst Section of Unione Astrofili Italiani ATA - Associazione Tuscolana di Astronomia In a large collaboration with: M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. … [View More]

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[vsnet-grb-info 37322] GRB 250210A: GRBAlpha detection
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39313 SUBJECT: GRB 250210A: GRBAlpha detection DATE: 25/02/13 21:51:35 GMT FROM: Lea Szakszonová <lea.szakszonova60(a)gmail.com> L. Szakszonova, M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner (Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak (Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Duriskova, M. Kolar,J.-P. Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal, A. Povalac (Brno U.… [View More] of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo, M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U. of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H. Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G. Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss (Konkoly Observatory), T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U. Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration. The long-duration GRB 250210A (FERMI/GBM: GCN Circular 39262, AstroSat/CZTI: GCN Circular 39267, INTEGRAL/SPI-ACS: CGN Circular 39268, SVOM/GRM: CGN Circular 39282) was observed by the GRBAlpha 1U CubeSat (Pal et al. 2023, A&A, 677, 40; https://ui.adsabs.harvard.edu/abs/2023A%26A...677A..40P/abstract). The detection was confirmed at the peak time 2025-02-10 05:32:02.5 UTC. The T90 duration measured by GRBAlpha is 22.5 s and the overall significance during T90 reaches 11.8 sigma. The light curve obtained by GRBAlpha is available here: https://grbalpha.konkoly.hu/static/share/GRB250210A_GCN.pdf All GRBAlpha detections are listed at: https://monoceros.physics.muni.cz/hea/GRBAlpha/ GRBAlpha, launched on 2021 March 22, is a demonstration mission for a future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy range from ~50 keV to ~1000 keV. To increase the duty cycle and the downlink rate, the upgrade of the on-board data acquisition software stack is in progress. The ground segment is also supported by the radio amateur community and it takes advantage of the SatNOGS network for increased data downlink volume. View this GCN Circular online at https://gcn.nasa.gov/circulars/39313. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 37321] EP250207B: Chandra localization of the X-ray counterpart
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39312 SUBJECT: EP250207B: Chandra localization of the X-ray counterpart DATE: 25/02/13 20:29:54 GMT FROM: Eleonora Troja <nora.gsfc(a)gmail.com> E. Troja (U Rome) reports on behalf of the ERC BHianca team: We imaged the field of the fast X-ray transient EP250207B (Zhou et al. GCN 39266) with the Chandra X-ray Observatory. Observations started on 2025 Feb 12.8 UT (~4.9 days after the trigger), using the ACIS-S instrument, for a total exposure time of … [View More]

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[vsnet-grb-info 37320] LIGO/Virgo/KAGRA S250206dm: FTW observations of counterpart candidates AT2025bbo and AT2025bcx, and of NED galaxies
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39311 SUBJECT: LIGO/Virgo/KAGRA S250206dm: FTW observations of counterpart candidates AT2025bbo and AT2025bcx, and of NED galaxies DATE: 25/02/13 20:19:59 GMT FROM: Malte Busmann at Ludwig-Maximilians-Universität München <m.busmann(a)physik.lmu.de> Malte Busmann (LMU), Daniel Gruen (LMU), Antonella Palmese (Carnegie Mellon U.), Brendan O’Connor (Carnegie Mellon U.), Yajie Zhang (LMU), Julius Gassert (LMU), Lei Hu (Carnegie Mellon U.), Arno Riffeser (… [View More]LMU/MPE), Julian Sommer (LMU), Lena Schnappinger (LMU), Franziska Krause (LMU) and Elia Engelhard (LMU) report: We observed transients discovered in the search for a counterpart of S250206dm (LIGO Scientific Collaboration et al., GCN 39175; LIGO Scientific Collaboration et al., GCN 39184) with the Three Channel Imager (3KK) at the Fraunhofer Telescope at Wendelstein Observatory (FTW) in the r, i, and J bands simultaneously. ### AT2025bbo We observed AT2025bbo (Smartt et al., GCN 39244; Liu et al., GCN 39249; Lee et al., GCN 39252; Ducoin et al., GCN 39258; Huber et al., GCN 39272; Karambelkar et al., GCN 39273; Chen et al., GCN 39285; Xu et al., GCN 39293) in riJ bands on 2025-02-09 and on 2025-02-10. Difference imaging of our data, between the two epochs (riJ) and against PS1 (ri) and UKIDSS (J) archival images, reveals no confident detection of a source. The depths of our observations are as follows: | Time (UT) | Band | Exposures | Depth (3 sigma, AB mag) | |---------------------|------|-----------|-------------------------| | 2025-02-09T21:26:34 | r | 10x 180s | 22.9 | | 2025-02-09T21:26:34 | i | 10x 180s | 22.7 | | 2025-02-09T21:26:48 | J | 10x 180s | 21.6 | | 2025-02-10T20:18:10 | r | 5x 180s | 22.3 | | 2025-02-10T20:18:10 | i | 5x 180s | 22.2 | | 2025-02-10T20:18:25 | J | 5x 180s | 21.2 | ### AT2025bcx We observed AT2025bcx for 8x 180s starting on 2025-02-10T18:40:45 and performed difference imaging in the r and i band with templates from PS1. In the difference images, we detect a source at the position of AT2025bcx at r = (20.5 +/- 0.2) mag and i = (20.9 +/- 0.3) mag. ### AT2025bmq Additionally, we have observed a list of NED galaxies selected from the list reported by Cook et al. (GCN 39235). We observed the first 11 candidate hosts as ranked by `P_3D_LumW1` in the night starting 2025-02-08. Typical depths in r,i bands are 21.5. Difference imaging w.r.t. PS1 reveals one candidate (AT2025bmq), consistent with being a nuclear transient in a host galaxy that shows previous activity. The r- and i-band magnitudes are calibrated against the PS1 catalog and the J-band is calibrated with the 2MASS Catalog. All magnitudes are provided in the AB system and are not corrected for Galactic extinction. We thank Christoph Ries and Michael Schmid from the Wendelstein Observatory staff for obtaining these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/39311. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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[vsnet-grb-info 37319] EP250207b: VLA radio upper limits
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39310 SUBJECT: EP250207b: VLA radio upper limits DATE: 25/02/13 15:29:42 GMT FROM: Roberto Ricci at INAF-IRA <ricci(a)ira.inaf.it> R. Ricci (U Rome), E. Troja (U Rome) and B. O'Connor (Carnegie Mellon) on behalf of a larger collaboration: We observed the Fast X-ray Transient EP250207b discovered by Einstein Probe (Zhou et al. GCN 39266) at the FXT position (Zhou et al. 39266) with the Very Large Array at the frequency of 6 GHz with a bandwidth of 4 … [View More]

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[vsnet-grb-info 37318] EP250212a: Liverpool Telescope optical upper limits
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39309 SUBJECT: EP250212a: Liverpool Telescope optical upper limits DATE: 25/02/13 08:45:55 GMT FROM: Rob Eyles-Ferris at U of Leicester <raje1(a)leicester.ac.uk> R. A. J. Eyles-Ferris, P. T. O’Brien and R. L. C. Starling (U of Leicester) report: We observed the field of the X-ray transient EP250212a (Li et al., GCN 39308) with the 2m Liverpool Telescope using the IO:O instrument. We obtained 5x90s exposures in the SDSS g’ filter starting at 2025-02-… [View More]

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[vsnet-grb-info 37317] EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
by GCN Circulars 13 Feb '25

13 Feb '25

TITLE: GCN CIRCULAR NUMBER: 39308 SUBJECT: EP250212a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient DATE: 25/02/13 03:17:51 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> D. Y. Li (NAOC, CAS), Y. J. Zhang(THU), Y. C. Fu (BNU), W. Yuan (NAOC, CAS) report on behalf of the Einstein Probe team: We report on the detection of a fast X-ray transient by EP-WXT, designated EP250212a (trigger ID: 10202399251). The WXT position of the source is R.A. = 114.949 … [View More]deg, DEC = 60.493 deg (J2000) with an uncertainty of 2.9 arcmin in radius (90% C.L. statistical and systematic). The transient started at 2025-02-12T07:44:07 (UTC) and lasted for about 360 seconds seen from WXT light curve. The average 0.5-4 keV spectrum can be fitted with an absorbed powerlaw model, with a NH of 0.5 (-0.3, +0.3) x 10^22 cm^-2 and a photon index of 2.2 (-0.9, +1.0). The derived average unabsorbed 0.5-4 keV flux is 0.9 (-0.3, +1.0) x10^-9 erg/s/cm2. The peak flux is about 6 x 10^-9 erg/s/cm2. The average spectrum also can be fitted with an absorbed blackbody model, with a NH upper limit of 0.45 x 10^22 cm^-2 and a temperature of 0.6 (-0.1, +0.2) keV. We performed a follow-up target of opportunity observation with EP-FXT. The observation began at 2025-02-12T13:20:16 (UTC) with an exposure time of 5970 seconds, about 5.6 hours after the burst detected by EP-WXT. Within the WXT error cirlce, an uncatalogued X-ray source was detected at R.A. = 114.9813 deg, DEC = 60.4848 deg (J2000) with an uncertainty of 10 arcsec in radius (90% C.L. statistical and systematic). The X-ray spectrum can be fitted with an absorbed powerlaw with the absorption fixed at the Galactic value of 6.3 x 10^20 cm^-2, and a photon index of 2.1 (-0.3, +0.3). The derived unabsorbed 0.5-10 keV flux is 3.2 (-0.7, +0.8) x 10^-13 erg/s/cm2. The uncertainties are at the 90% confidence level for the above parameters. The FXT spectrum can not be well fitted with a black body model. A J-band upper limit of 20.9 mag was given by a NOT observation performed about 12.3 hour after the EP trigger (GCN 39306). 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/39308. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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