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

[vsnet-grb-info 38410] GRB 250507A: refined SVOM/MXT data analysis
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40381 SUBJECT: GRB 250507A: refined SVOM/MXT data analysis DATE: 25/05/07 14:04:48 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> P. Maggi (ObAS), D. Götz (CEA), H. Goto (Kanazawa University/CEA), M. Moita (CEA), C. Plasse (CEA), F. Robinet (IJCLab), C. Van Hove (IJCLab) report of behalf of the SVOM/MXT Team: GRB 250507A (Wang et al. GCN 40374) was observed by SVOM/MXT after an automatic SVOM slew, starting at T0 = 2025-05-07T06:40:59.951 (374s after … [View More]

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[vsnet-grb-info 38409] GRB 250507A: REM optical/NIR observations
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40380 SUBJECT: GRB 250507A: REM optical/NIR observations DATE: 25/05/07 12:09:00 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro, P. D'Avanzo, S. Covino, D. Fugazza (INAF-OAB), M. De Pasquale (Univ. of Messina) report on behalf of the REM team: We observed the field of GRB 250507A detected by SVOM/ECLAIRs (Wang et al., GCN 40374) with the REM 60 cm robotic telescope located at the ESO observatory of La Silla (… [View More]

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[vsnet-grb-info 38408] GRB 250507A: SVOM/VT optical upper limit
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40379 SUBJECT: GRB 250507A: SVOM/VT optical upper limit DATE: 25/05/07 11:01:12 GMT FROM: Liping Xin at NAOC, SVOM <xlp(a)nao.cas.cn> L. P. Xin, Y. L. Qiu, H. L. Li, C. Wu, Z. H. Yao, Y. N. Ma, X. H. Han, Y. Xu, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio (CEA), Z. Q. Wang (GXU), Y. F. Liang (PMO), W. K. Zheng (UCB) report on behalf of the SVOM/VT instrument team. After the trigger by … [View More]

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[vsnet-grb-info 38407] GRB 250506A: Swift-XRT observations
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40378 SUBJECT: GRB 250506A: Swift-XRT observations DATE: 25/05/07 09:35:26 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), M. A. Williams (PSU), S. Dichiara (PSU) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of the … [View More]

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[vsnet-grb-info 38406] Fermi-LAT Gamma-ray Observations of IceCube-250506A
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40377 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-250506A DATE: 25/05/07 09:11:45 GMT FROM: Leo Pfeiffer at University of Würzburg <pfeiffer.leo(a)gmail.com> L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg), S. Garrappa (Weizmann Institute of Science) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC250506A neutrino event (GCN 40369) with all-sky survey … [View More]

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[vsnet-grb-info 38405] GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40376 SUBJECT: GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit DATE: 25/05/07 08:57:04 GMT FROM: J.-G. Ducoin at CPPM <ducoin(a)cppm.in2p3.fr> Jean-Grégoire Ducoin (CPPM), Alan M. Watson (UNAM), Fredd Alvarez (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Alan M. Watson (UNAM), Fredd Alvarez (UNAM), Jean-Luc Atteia (IRAP), Camila Angulo (UNAM), Dalya Akl (AUS), Sarah Antier (OCA), Rosa L. Becerra (U Roma), Nathaniel R. Butler (ASU) … [View More]

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[vsnet-grb-info 38404] EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40375 SUBJECT: EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032 DATE: 25/05/07 07:38:27 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H. Sun, M. H. Zhang, H. Q. Cheng (NAO, CAS), Y. J. Zhang (THU), W. Yuan (NAO, CAS) report on behalf of the Einstein Probe team: We report on the detection of a new X-ray outburst of the low-mass X-ray binary (LMXB) MAXI J1957+032 by the Wide-field X-ray Telescope (WXT) on board the Einstein … [View More]Probe (EP) mission. The burst triggered EP-WXT (ID: 01709175213) at 2025-05-06T21:07:59 (UTC). The source light curve lasted for 74 seconds before the observation was interrupted by the follow-up observation. The WXT position of the source, inferred from the onground analysis, is R.A. = 299.150 deg, DEC = 3.444 deg (J2000) with an uncertainty of 2.8 arcmin in radius (90% C.L. statistical and systematic). The averaged WXT spectrum in 0.5-4 keV can be fitted by an absorbed power law model with a photon index of 1.82 (-0.56, +0.62) when fixing the column density at 1.7 x 10^21 cm^-2 (Sánchez et al. 2017). The average unabsorbed 0.5-4 keV flux is 7.6 (-1.7,+2.2) x 10^-10 erg/cm^2/s. Following the WXT trigger, a follow-up observation with the Follow-up X-ray Telescope (FXT) was performed automatically. The FXT observation started at 2025-05-06T21:08:30 (UTC), around 30 seconds after the trigger. The analysis of the data, with an exposure of 1.6 ks, reveals a detection of an X-ray source at RA = 299.1636 deg, Dec = 3.4449 deg (J2000) with an uncertainty of 10 arcsec in radius (90% C.L. statistical and systematic). This position is consistent with the known LMXB MAXI J1957+032 (also named as IGR J19566+0326), confirming the WXT detection as the outburst of this X-ray source. The averaged FXT spectrum in 0.5-10 keV can be fitted by an absorbed power law model with a photon index of 1.85 (-/+ 0.02) when fixing the column density at 1.7 x 10^21 cm^-2. The average unabsorbed 0.5-10 keV flux is 9.1 (-/+ 0.1) x 10^-10 erg/cm^2/s, which is consistent with the flux detected by the WXT. These parameters derived are at the 1-sigma confidence level. The previous outburst of MAXI J1957+032 happened at the end of September 2016 and lasted for around 4 days. Its X-ray flux was approximately 7 x 10^-13 erg/cm^2/s in 2022 before the outburst, inferred from the Swift/XRT observation. We thus suggest that MAXI J1957+032 has entered a new outburst phase. Contact transient advocate (TA) for MAXI J1957+032 is H. Sun (hsun(a)nao.cas.cn) and please contact the TA for information regarding the EP observation of this source. Reference: Sánchez et al. 2017, MNRAS, 468, 564 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/40375. --- 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 38403] GRB 250507A: SVOM detection of a long burst
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40374 SUBJECT: GRB 250507A: SVOM detection of a long burst DATE: 25/05/07 07:23:04 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Z. Wang (GXU), Y. Liang (PMO), H. Yang, O. Godet (IRAP), P. Maggi (ObAS), D. Götz (CEA), L Xin (NAOC) report on behalf of the SVOM mission team: SVOM/ECLAIRs triggered on the gamma-ray burst GRB 250507A (SVOM burst-id sb25050703) starting at 2025-05-07T06:34:45.17 UTC (Tb). The following trigger information was received on … [View More]the ground with low latency by the SVOM VHF Alert Network. The burst was detected by the Count-Rate Trigger (CRT) and Image Trigger (IMT). A sequence of 10 alerts was produced. IMT provided the alert with the best signal-to-noise-ratio (SNR) of 10.65 in the 8-120 keV energy band over a time window of 40.96 seconds starting at Tb. The localization of the best alert is R.A., Dec. 182.990, -23.615 degrees: R.A. (J2000) = 12h11m57.6s Dec. (J2000) = -23h36m54s with a 90% confidence level (C.L.) radius of 7.5 arcmin (including systematic error of 2 arcmin added in quadrature). SVOM slewed to the burst. MXT began observing the field after the slew, starting at 2025-05-07T06:41:02 i.e. 377 s after Tb. Using onboard processed data we found an uncatalogued X-ray source located at R.A., Dec 183.074, -23.598 degrees: R.A. (J2000) = 12h12m17.76s Dec. (J2000) = -23d35m52.8s with a 90% C.L. radius of 30 arcseconds (including 25 arcseconds systematic error added in quadrature). This location is 4.7’ from the ECLAIRs onboard position. This position may be improved as more data is received. VT began observing the field after the slew. The analysis of the recorded images will be published in a future circular gathering information on the follow-up of the SVOM optical instruments. 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. The Burst Advocate (BA) on shift for this burst is Ziqi Wang: ziqi.wang(a)st.gxu.edu.cn. Please contact the BA by email if you require additional information regarding the SVOM follow-up of this burst. View this GCN Circular online at https://gcn.nasa.gov/circulars/40374. --- 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 38402] GRB 250506A: Mephisto optical upper limits
by GCN Circulars 07 May '25

07 May '25

TITLE: GCN CIRCULAR NUMBER: 40373 SUBJECT: GRB 250506A: Mephisto optical upper limits DATE: 25/05/07 02:43:57 GMT FROM: Brajesh Kumar at SWIFAR, YNU <brajesh(a)ynu.edu.cn> Dezi Liu, Ziwei Li, Tao Wang, Shuang Lin, Xiangru Qian, Guowang Du, Xingzhu Zou, Yu Pan, Xinlei Chen, Xufeng Zhu, Helong Guo, Yuan Fang, Jinghua Zhang, Chenxu Liu, Edoardo Lagioia, Brajesh Kumar, Jianhui Lian, Yuanpei Yang, Xiangkun Liu, Xiaowei Liu (all SWIFAR, YNU) report on behalf of the Mephisto Team: We … [View More]

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[vsnet-grb-info 38401] GRB 250504A: EIRSAT-1 GMOD Detection
by GCN Circulars 06 May '25

06 May '25

TITLE: GCN CIRCULAR NUMBER: 40372 SUBJECT: GRB 250504A: EIRSAT-1 GMOD Detection DATE: 25/05/06 21:03:59 GMT FROM: Padraig McDermott at University College Dublin <padraig.mcdermott(a)ucdconnect.ie> P. McDermott, D. Murphy, C. McKenna, C. de Barra, A. Ulyanov, G. Finneran, G. Corcoran, L. Cotter, A. Empey, J. Fisher, F. Gibson Kiely, J. Thompson, D. McKeown, A. Martin-Carrillo, L. Hanlon, S. McBreen, on behalf of the EIRSAT-1 team: EIRSAT-1 reports the detection of the long … [View More]

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