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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 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…

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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 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…

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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 initial UVOT exposures. The source is detected in all filters except for uvw2 and only marginally in uvm2, which would be consistent with the redshift reported by de Ugarte Postigo et al. (GCN Circ. 40901). The preliminary UVOT position is: RA (J2000) = 14:11:44.66 = 212.93610 (deg.) Dec (J2000) = +16:44:55.1 = 16.74863 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 97 247 147 15.86 +/- 0.02 v 5904 6104 197 18.39 +/- 0.14 b 3878 4077 197 18.42 +/- 0.09 u 309 515 202 15.04 +/- 0.03 m2 9609 10131 514 19.53 +/- 0.24 w2 5699 5899 197 >19.2 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.017 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/40933. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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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 Florence), P. S. Marrocchesi (U of Siena), and the CALET collaboration: The long GRB 250702A (Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 40881; BALROG localization: Preis et al., GCN Circ 40882; Fermi GBM Detection: Malacaria et al., GCN Circ. 40887; GECAM-B detection: Wang et al., GCN Circ. 40992) triggered the CALET Gamma-ray Burst Monitor (CGBM) at 09:54:05.81 UTC on 2 July 2025 (https://cgbm.calet.jp/cgbm_trigger/flight/1435484973/index.html). The burst signal was seen by all CGBM detectors. The burst light curve shows a single pulse that starts at T+1.5 sec, peaks at T+6.2 sec, and ends at T+14.4 sec. The T90 and T50 durations measured by the SGM data are 10.5 +/- 0.6 sec and 3.9 +/- 0.3 sec (40-1000 keV), respectively. The ground-processed light curve is available at https://cgbm.calet.jp/cgbm_trigger/ground/1435484973 The CALET data used in this analysis are provided by the Waseda CALET Operation Center located at Waseda University. View this GCN Circular online at https://gcn.nasa.gov/circulars/40932. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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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, 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…

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[vsnet-grb-info 38977] Fermi GRB 250703A: Global MASTER-Net observations report
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40930 SUBJECT: Fermi GRB 250703A: Global MASTER-Net observations report DATE: 25/07/04 03:30:23 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250703A ( Fermi GBM team, GCN 40909) errorbox 54105 sec after notice time and 54115 sec after trigger time at 2025-07-04 00:09:27 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 65 deg. The sun altitude is -68.8 deg. The galactic latitude b = -27 deg., longitude l = 88 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2924032 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 54146 | 2025-07-04 00:09:27 | MASTER-SAAO | (22h 26m 03.93s , +25d 31m 00.0s) | C | 60 | 18.5 | 54146 | 2025-07-04 00:09:27 | MASTER-SAAO | (22h 24m 08.95s , +25d 46m 54.4s) | C | 60 | 18.4 | 54360 | 2025-07-04 00:13:01 | MASTER-SAAO | (22h 34m 58.48s , +25d 30m 12.9s) | C | 60 | 19.1 | 54360 | 2025-07-04 00:13:01 | MASTER-SAAO | (22h 33m 03.49s , +25d 46m 08.2s) | C | 60 | 19.0 | 54650 | 2025-07-04 00:17:51 | MASTER-SAAO | (22h 22m 02.32s , +23d 35m 41.4s) | C | 60 | 19.0 | 54744 | 2025-07-04 00:19:25 | MASTER-SAAO | (22h 30m 48.83s , +23d 37m 23.1s) | C | 60 | 18.4 | 54744 | 2025-07-04 00:19:25 | MASTER-SAAO | (22h 28m 54.92s , +23d 53m 18.7s) | C | 60 | 18.4 | 54838 | 2025-07-04 00:20:59 | MASTER-SAAO | (22h 26m 00.65s , +25d 30m 36.9s) | C | 60 | 17.6 | 54838 | 2025-07-04 00:20:59 | MASTER-SAAO | (22h 24m 05.05s , +25d 46m 32.8s) | C | 60 | 17.5 | 55038 | 2025-07-04 00:24:19 | MASTER-SAAO | (22h 34m 59.98s , +25d 30m 21.6s) | C | 60 | 18.7 | 55038 | 2025-07-04 00:24:19 | MASTER-SAAO | (22h 33m 04.25s , +25d 46m 18.0s) | C | 60 | 18.6 | 55530 | 2025-07-04 00:32:31 | MASTER-SAAO | (22h 22m 03.38s , +23d 35m 59.0s) | C | 60 | 16.4 | 55624 | 2025-07-04 00:34:05 | MASTER-SAAO | (22h 30m 50.57s , +23d 37m 31.6s) | C | 60 | 18.2 | 55624 | 2025-07-04 00:34:05 | MASTER-SAAO | (22h 28m 55.96s , +23d 53m 28.4s) | C | 60 | 18.1 | 55717 | 2025-07-04 00:35:38 | MASTER-SAAO | (22h 26m 03.12s , +25d 30m 45.9s) | C | 60 | 16.1 | 55717 | 2025-07-04 00:35:38 | MASTER-SAAO | (22h 24m 06.74s , +25d 46m 43.2s) | C | 60 | 16.1 | 58382 | 2025-07-04 01:20:03 | MASTER-SAAO | (22h 34m 57.08s , +25d 32m 08.2s) | C | 60 | 17.9 | 58382 | 2025-07-04 01:20:03 | MASTER-SAAO | (22h 33m 00.18s , +25d 47m 59.5s) | C | 60 | 17.7 | 59961 | 2025-07-04 01:46:22 | MASTER-SAAO | (22h 22m 20.57s , +23d 37m 14.0s) | C | 60 | 18.6 | 59961 | 2025-07-04 01:46:22 | MASTER-SAAO | (22h 20m 26.03s , +23d 53m 02.5s) | C | 60 | 18.4 | 60055 | 2025-07-04 01:47:56 | MASTER-SAAO | (22h 31m 09.34s , +23d 37m 00.4s) | C | 60 | 17.5 | 60055 | 2025-07-04 01:47:56 | MASTER-SAAO | (22h 29m 14.85s , +23d 52m 49.9s) | C | 60 | 17.3 | 60151 | 2025-07-04 01:49:32 | MASTER-SAAO | (22h 26m 26.43s , +25d 32m 54.5s) | C | 60 | 16.6 | 60151 | 2025-07-04 01:49:32 | MASTER-SAAO | (22h 24m 30.30s , +25d 48m 45.4s) | C | 60 | 16.3 | 60345 | 2025-07-04 01:52:46 | MASTER-SAAO | (22h 35m 20.05s , +25d 32m 35.8s) | C | 60 | 15.5 | 60345 | 2025-07-04 01:52:46 | MASTER-SAAO | (22h 33m 23.77s , +25d 48m 27.9s) | C | 60 | 15.3 | 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/40930. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38976] Fermi GRB 250703A: Global MASTER-Net observations report
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40930 SUBJECT: Fermi GRB 250703A: Global MASTER-Net observations report DATE: 25/07/04 03:30:23 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, 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.Sosnovskij (CrAO), 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-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 250703A ( Fermi GBM team, GCN 40909) errorbox 54105 sec after notice time and 54115 sec after trigger time at 2025-07-04 00:09:27 UT, with upper limit up to 19.1 mag. The observations began at zenith distance = 65 deg. The sun altitude is -68.8 deg. The galactic latitude b = -27 deg., longitude l = 88 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=2924032 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 54146 | 2025-07-04 00:09:27 | MASTER-SAAO | (22h 26m 03.93s , +25d 31m 00.0s) | C | 60 | 18.5 | 54146 | 2025-07-04 00:09:27 | MASTER-SAAO | (22h 24m 08.95s , +25d 46m 54.4s) | C | 60 | 18.4 | 54360 | 2025-07-04 00:13:01 | MASTER-SAAO | (22h 34m 58.48s , +25d 30m 12.9s) | C | 60 | 19.1 | 54360 | 2025-07-04 00:13:01 | MASTER-SAAO | (22h 33m 03.49s , +25d 46m 08.2s) | C | 60 | 19.0 | 54650 | 2025-07-04 00:17:51 | MASTER-SAAO | (22h 22m 02.32s , +23d 35m 41.4s) | C | 60 | 19.0 | 54744 | 2025-07-04 00:19:25 | MASTER-SAAO | (22h 30m 48.83s , +23d 37m 23.1s) | C | 60 | 18.4 | 54744 | 2025-07-04 00:19:25 | MASTER-SAAO | (22h 28m 54.92s , +23d 53m 18.7s) | C | 60 | 18.4 | 54838 | 2025-07-04 00:20:59 | MASTER-SAAO | (22h 26m 00.65s , +25d 30m 36.9s) | C | 60 | 17.6 | 54838 | 2025-07-04 00:20:59 | MASTER-SAAO | (22h 24m 05.05s , +25d 46m 32.8s) | C | 60 | 17.5 | 55038 | 2025-07-04 00:24:19 | MASTER-SAAO | (22h 34m 59.98s , +25d 30m 21.6s) | C | 60 | 18.7 | 55038 | 2025-07-04 00:24:19 | MASTER-SAAO | (22h 33m 04.25s , +25d 46m 18.0s) | C | 60 | 18.6 | 55530 | 2025-07-04 00:32:31 | MASTER-SAAO | (22h 22m 03.38s , +23d 35m 59.0s) | C | 60 | 16.4 | 55624 | 2025-07-04 00:34:05 | MASTER-SAAO | (22h 30m 50.57s , +23d 37m 31.6s) | C | 60 | 18.2 | 55624 | 2025-07-04 00:34:05 | MASTER-SAAO | (22h 28m 55.96s , +23d 53m 28.4s) | C | 60 | 18.1 | 55717 | 2025-07-04 00:35:38 | MASTER-SAAO | (22h 26m 03.12s , +25d 30m 45.9s) | C | 60 | 16.1 | 55717 | 2025-07-04 00:35:38 | MASTER-SAAO | (22h 24m 06.74s , +25d 46m 43.2s) | C | 60 | 16.1 | 58382 | 2025-07-04 01:20:03 | MASTER-SAAO | (22h 34m 57.08s , +25d 32m 08.2s) | C | 60 | 17.9 | 58382 | 2025-07-04 01:20:03 | MASTER-SAAO | (22h 33m 00.18s , +25d 47m 59.5s) | C | 60 | 17.7 | 59961 | 2025-07-04 01:46:22 | MASTER-SAAO | (22h 22m 20.57s , +23d 37m 14.0s) | C | 60 | 18.6 | 59961 | 2025-07-04 01:46:22 | MASTER-SAAO | (22h 20m 26.03s , +23d 53m 02.5s) | C | 60 | 18.4 | 60055 | 2025-07-04 01:47:56 | MASTER-SAAO | (22h 31m 09.34s , +23d 37m 00.4s) | C | 60 | 17.5 | 60055 | 2025-07-04 01:47:56 | MASTER-SAAO | (22h 29m 14.85s , +23d 52m 49.9s) | C | 60 | 17.3 | 60151 | 2025-07-04 01:49:32 | MASTER-SAAO | (22h 26m 26.43s , +25d 32m 54.5s) | C | 60 | 16.6 | 60151 | 2025-07-04 01:49:32 | MASTER-SAAO | (22h 24m 30.30s , +25d 48m 45.4s) | C | 60 | 16.3 | 60345 | 2025-07-04 01:52:46 | MASTER-SAAO | (22h 35m 20.05s , +25d 32m 35.8s) | C | 60 | 15.5 | 60345 | 2025-07-04 01:52:46 | MASTER-SAAO | (22h 33m 23.77s , +25d 48m 27.9s) | C | 60 | 15.3 | 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/40930. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38975] GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40929 SUBJECT: GRBs 250702B,C,D,E / EP250702a: 2.2m CAHA optical upper limit DATE: 25/07/04 02:24:14 GMT FROM: I. Perez-Garcia at Institute of Astrophysics of Andalusia <ipg(a)iaa.es> I. Pérez-García, A. J. Castro-Tirado, M. D. Caballero-García, S. Guziy, R. Sánchez-Ramírez, S.-Y. Wu (IAA-CSIC Granada), G. García-Segura (Instituto de Astronomía de la UNAM, Ensenada), M. Gritsevich (Univ. of Helsinki), Y.-D. Hu (Guanxi Univ.), S. Góngora-García and J.-F.Agüí-Fernández (CAHA), on behalf of a larger collaboration, report: We observed the location of EP250702a (Cheng et al., GCN 40906, 40917), associated with the four high-energy events GRB 250702B,C,D,E, all detected by Fermi/GBM (Fermi GBM Team, GCN 40883, 40885, 40886, 40890), Swift/BAT (GUANO system; DeLaunay et al., GCN 40903) and Konus/Wind (Frederiks et al., GCN 40914), with all these events likely originating from the same astrophysical source (Neights et al., GCN 40891). Using the 2.2m CAHA telescope in Spain (equipped with CAFOS), we obtained 60s exposures in the z-band, starting on 2025 July 3 at 23.99 UT (i.e. 34.1 hr after the first Fermi trigger, GRB 250702B). At the location of the UVOT-enhanced position provided by Swift/XRT (Kennea et al., GCN 40919) and the VLT nIR source reported by Martin-Carrillo et al. (GCN 40924), we do not detect an optical source on the co-added z-band (1980s total exposure time) down to z = 21.4 (3-sigma limiting magnitude), using the Pan-STARRS1 DR2 (Magnier et al. 2025) catalogue as reference. We thank the staff at CAHA for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/40929. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38974] GRB 250702F: Swift-XRT refined Analysis
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40928 SUBJECT: GRB 250702F: Swift-XRT refined Analysis DATE: 25/07/04 00:28:33 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> J.P. Osborne (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti (INAF-OAB), C. Salvaggio (INAF-OAB), D.N. Burrows (PSU), M.A. Williams (PSU), S. Dichiara (PSU), K.L. Page (U. Leicester) and P.A. Evans report on behalf of the Swift-XRT team: We have analysed 5.2 ks of XRT data for GRB 250702F, from 94 s to 94.1 ks after the trigger. The data comprise 420 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+3.9 ks) can be modelled with a power-law decay with a decay index of alpha=1.01 (+/-0.06). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.016 (+/-0.029). The best-fitting absorption column is 3.5 (+/-0.5) x 10^21 cm^-2, at a redshift of 1.52, in addition to the Galactic value of 1.3 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has a photon index of 1.95 (+/-0.13) and a best-fitting absorption column of 2.1 (+2.1, -1.9) x 10^21 cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (3.7 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 1.3 x 10^20 cm^-2 Intrinsic column: 2.1 (+2.1, -1.9) x 10^21 cm^-2 at z=1.52 Photon index: 1.95 (+/-0.13) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01329888. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/40928. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38973] GRB 250702F: Fermi GBM Observation
by GCN Circulars 04 Jul '25

04 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40927 SUBJECT: GRB 250702F: Fermi GBM Observation DATE: 25/07/04 00:25:21 GMT FROM: oindabimukherjee(a)gmail.com O. Mukherjee (USRA) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 21:06:43.10 UT on 02 July 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250702F (trigger 773183208/250702880). which was also detected by Swift BAT (N. J. Klingler et al. 2025), GOTO (A. Kumar et al. 2025, GCN 40896), AKO (Mohammad Odeh et al. 2025, GCN 40925). A spectroscopic redshift of z = 1.52 was reported by GTC/OSIRIS (A. de Ugarte Postigo et al. 2025, GCN 40901) The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 43 degrees. The GBM light curve consists of multiple pulses with a duration (T90) of about 54 s (50-300 keV). The time-averaged spectrum from T0-29 to T0+48 s is best fit by a band function with alpha = -1.34 +/- 0.06 and beta = -1.78 +/- 0.09 and the cutoff energy, parameterized as Epeak, is 403 +/- 148 keV. The event fluence (10-1000 keV) in this time interval is (1.45 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+38 s in the 10-1000 keV band is 9.7 +/- 0.3 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/40927. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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