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

[vsnet-grb-info 38987] GRB 250704B: SVOM/GRM observation of a short burst
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40940 SUBJECT: GRB 250704B: SVOM/GRM observation of a short burst DATE: 25/07/04 09:10:04 GMT FROM: Chenwei Wang at IHEP <cwwang(a)ihep.ac.cn> SVOM/GRM team: Chen-Wei Wang, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Ulysse Jacob (LUPM) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by a short burst GRB 250704B (SVOM trigger reference: sb25070406) at 2025-07-04T08:16:27.100 UTC (T0). … [View More]

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[vsnet-grb-info 38986] GRB 250702F: optical photometry from Konkoly
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40939 SUBJECT: GRB 250702F: optical photometry from Konkoly DATE: 25/07/04 08:55:20 GMT FROM: Jozsef Vinko at Konkoly Observator <vinko(a)konkoly.hu> GRB 250702F: optical photometry from Konkoly J. Vinko, K. Sarneczky, A. Horti-David, R. Konyves-Toth, Zs. Bora, L. Kriskovics, A. Pal, R. Szakats (Konkoly Observatory, Hungary) We report detection and photometry of the optical afterglow of GRB 250702F (Fermi GRB team, GCN 40892; Klinger et al. GCN … [View More]

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[vsnet-grb-info 38985] GRB 250407A: REM detection of the optical afterglow
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40938 SUBJECT: GRB 250407A: REM detection of the optical afterglow DATE: 25/07/04 07:59:57 GMT FROM: Riccardo Brivio at INAF-OAB <riccardo.brivio(a)inaf.it> R. Brivio, M. Ferro (INAF-OAB), S. D. Vergani (LUX-Paris Obs.), A. Melandri (INAF-OAR), P. D'Avanzo, S. Covino, D. Fugazza (INAF-OAB) report on behalf of the REM team: We observed the field of GRB 250704A detected by SVOM (Cao et al., GCN 40934) with the REM 60 cm robotic telescope located at the … [View More]

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[vsnet-grb-info 38984] LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40937 SUBJECT: LIGO/Virgo/KAGRA S250704ab: Coverage and upper limits from MAXI/GSC observations DATE: 25/07/04 06:49:21 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo(a)phys.aoyama.ac.jp> H. Negoro, M. Nakajima, K. Takagi (Nihon U.), N. Kawai, T. Mihara, (RIKEN), S. Sugita, M. Serino, Y. Kawakubo, H. Hiramatsu, Y. Kondo (AGU) report on behalf of the MAXI team: We examined MAXI/GSC all-sky X-ray images (2-20 keV) after compact binary … [View More]

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[vsnet-grb-info 38983] GRB 250702F: SVOM/VT optical observation
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40936 SUBJECT: GRB 250702F: SVOM/VT optical observation DATE: 25/07/04 05:57:52 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Y.N. Ma, L. P. Xin, Y. L. Qiu, C. Wu, H. L. Li, Z. H. Yao, 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. Palmerio (CEA), Y. H. Cheng(YNU), J. X. Cao(GXU) report on behalf of the SVOM/VT team SVOM/VT performed a Target of Opportunity observation of GRB 250702F … [View More]

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[vsnet-grb-info 38982] LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40935 SUBJECT: LIGO/Virgo/KAGRA S250704ab: Identification of a GW compact binary merger candidate DATE: 25/07/04 05:24:59 GMT FROM: Pan Guo at KAGRA <panguocas(a)gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250704ab during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo … [View More]Observatory (V1) at 2025-07-04 04:30:48.040 UTC (GPS time: 1435638666.040). The candidate was found by the cWB [1], cWB BBH [2], GstLAL [3], MBTA [4], and PyCBC Live [5] analysis pipelines. S250704ab is an event of interest because its false alarm rate, as estimated by the online analysis, is 3.2e-10 Hz, or about one in 1e2 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250704ab The initial classification of the GW signal, in order of descending probability, based on chirp-mass information only [5], is BBH (82%), NSBH (17%), Terrestrial (<1%), or BNS (<1%). Assuming the candidate is astrophysical in origin, the probability that at least one of the compact objects is consistent with a neutron star mass (HasNS) is <1%. [6] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [6] Both HasNS and HasRemnant consider the support of several neutron star equations of state for maximum neutron star mass. The probability that either of the binary components lies between 3 and 5 solar masses (HasMassGap) is 14%. The source chirp mass falls with highest probability in the bin (5.5, 11.0) solar masses, assuming the candidate is astrophysical in origin. Two sky maps are available at this time and can be retrieved from the GraceDB event page: * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [7], distributed via GCN and SCiMMA notices about 27 seconds after the candidate event time. * bayestar.multiorder.fits,2, an initial localization generated by BAYESTAR [7], distributed via GCN and SCiMMA notices about 5 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,2. For the bayestar.multiorder.fits,2 sky map, the 90% credible region is 77 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 536 +/- 124 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] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [2] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [3] Tsukada et al. PRD 108, 043004 (2023) doi:10.1103/PhysRevD.108.043004 and Ewing et al. PRD 109, 042008 (2024) doi:10.1103/PhysRevD.109.042008 [4] Alléné et al. CQG 42, 105009 (2025) doi:10.1088/1361-6382/add234 [5] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [6] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [7] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/40935. --- 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 38981] GRB 250704A: SVOM detection of a burst
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40934 SUBJECT: GRB 250704A: SVOM detection of a burst DATE: 25/07/04 05:09:08 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> J.X Cao (GXU), Y.H Cheng (SWIFAR, YNU), W.J Xie (NAOC), D.H Zhao (NAOC), N. Dagoneau (CEA), L. Zhang (IHEP), C. Van Hove (IJCLab), P. Maggi (ObAS) report on behalf of the SVOM mission team: At 2025-07-04T03:42:22 UTC (T0), SVOM/ECLAIRs triggered and located the gamma-ray burst GRB 250704A (SVOM burst-id sb25070404). The … [View More]following trigger information was received on the ground with low latency by the SVOM VHF Alert Network. The burst was detected both by the Count-Rate Trigger (CRT) and the Image Trigger (IMT), which produced a sequence of 11 alerts. CRT provided the alert with the best signal-to-noise-ratio (SNR) in the image of 11.88 in the [8-120] keV energy band over a time window of 5.10 seconds starting at 2025-07-04T03:42:20. The localization of the best alert is R.A., Dec. 17.1325, -17.2798 degrees (J2000) with a 90% confidence level (C.L.) radius of 6.78 arcmin (including systematic error of 2 arcmin added in quadrature). This burst also triggered SVOM/GRM at 2025-07-04T03:42:20 with a SNR of 9.20. The SVOM/GRM light curve showed a single peak structure with a duration of about 8 seconds. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb250704A.png. SVOM/MXT began observing the field at 2025-07-04T03:45:35 UTC, 192 seconds after T0. Using data rapidly transmitted to the ground via the VHF network, we found an uncatalogued X-ray source located at R.A., Dec. 17.1760, -17.3394 degrees: R.A. (J2000) = 1h08m42.24s Dec. (J2000) = -17d20m21.8s with a 90% C.L. radius of 102 arcseconds (including a systematic uncertainty of 35 arcseconds added in quadrature). This location is 4.36 arcminutes from the ECLAIRs onboard position. This position may be improved as more data is received in the full X-band dataset. VT began observing the field after the slew. The analysis of the data will be published in a future circular. 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 Jiaxin Cao: cjx(a)st.gxu.edu.cn. Please contact the BA by email if you require additional information. View this GCN Circular online at https://gcn.nasa.gov/circulars/40934. --- 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 38980] GRB 250702F: Swift/UVOT Detection
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40933 SUBJECT: GRB 250702F: Swift/UVOT Detection DATE: 25/07/04 05:01:32 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) and N. J. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 250702F 97 s after the BAT trigger (Klingler et al., GCN Circ. 40894). A source consistent with the XRT position (Goad et al., GCN Circ. 40902) is detected in the … [View More]

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[vsnet-grb-info 38979] GRB 250702A: CALET Gamma-Ray Burst Monitor detection
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40932 SUBJECT: GRB 250702A: CALET Gamma-Ray Burst Monitor detection DATE: 25/07/04 04:55:55 GMT FROM: Yuta Kawakubo at Aoyama Gakuin University <kawakubo(a)phys.aoyama.ac.jp> K. Kobayashi (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita, Y. Kawakubo (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), Y. Asaoka (ICRR), S. Torii, Y. Akaike, (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC), M. L. Cherry (LSU), S. Ricciarini (U of … [View More]

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[vsnet-grb-info 38978] Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40931 SUBJECT: Fermi GBM Analysis of GRB 250702B (formerly B,D,E); dissociation of C burst DATE: 25/07/04 03:47:31 GMT FROM: eliza.neights(a)gmail.com E. Neights (GWU, NASA GSFC), O.J. Roberts (USRA, NASA MSFC), E. Burns (LSU), P. Veres (UAH), E. Bissaldi (Politecnico and INFN Bari) report on behalf of the Fermi-GBM Team: On July 2, 2025, Fermi-GBM triggered four times on gamma-ray emission emanating from a similar localization of the sky (GCNs 40883, … [View More]40885, 40886, 40890, 40891), over an interval of 11.5 ks, believed likely to be from the same source. Konus-Wind observations (GCN 40914) provide further support that these triggers may be related to a similar origin, but with a combined duration of >15 ks. A combined GBM skymap was found to be spatially consistent with Swift-BAT GUANO detections of 250702D, C and E (GCN 40903). Emission from 250702E was found to be spatially and temporally coincident with Einstein Probe Transient, EP250702a (GCN 40906, 40917). While it is currently named with the phenomenological GRB convention, the physical origin is still uncertain. Upon further investigation, the pulse which caused the GBM trigger labeled 250702C was from an unrelated short GRB. That is, emission from the short burst and the ultra-long 250702B are contemporaneous, but arise from inconsistent locations. In light of this, spectral analysis was conducted for the three triggers of GRB 250702B, matched to their previous designations below. We observe photons in the BGO up to 1 MeV, with the majority of the photons occurring in the 50-300 keV range. The spectral analyses of these events are summarized below, which are fit about equally well with power law and Band function models: GRB Name | Trigger Time/T0 (UT) | Interval (s) | Power Law Index | Fluence (erg/cm2) 250702E | 16:21:33.07 | T0-6.1 - T0+147.5 | -1.38 +/- 0.01 | (2.74 +/- 0.05)E-05 250702B | 13:56:05.77 | T0-30.7 - T0+26.6 | -1.34 +/- 0.01 | (1.24 +/- 0.03)E-05 250702D | 13:09:02.03 | T0-95.2 - T0+12.3 | -1.29 +/- 0.02 | (1.04 +/- 0.05)E-05 GRB Name | Trigger Time/T0 (UT) | Interval (s) | Band Alpha | Band Beta | Band Peak Energy (keV) | Fluence (erg/cm2) 250702E | 16:21:33.07 | T0-6.1 - T0+147.5 | -0.81 +/- 0.05 | -5.1 +/- 22.7 | 610 +/- 60 | (3.4 +/- 0.1)E-05 250702B | 13:56:05.77 | T0-30.7 - T0+26.6 | -0.8 +/- 0.1 | -1.52 +/- 0.04 | 400 +/- 200 | (1.38 +/- 0.05)E-05 250702D | 13:09:02.03 | T0-95.2 - T0+12.3 | -0.2 +/- 0.3 | -1.7 +/- 0.1 | 400 +/- 100 | (1.48 +/- 0.09)E-05 View this GCN Circular online at https://gcn.nasa.gov/circulars/40931. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L… [View Less]

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