vsnet-grb-info July 2025

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[vsnet-grb-info 38925] GRB 250702A: Fermi GBM Final Real-time Localization
by GCN Circulars 02 Jul '25

02 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40881 SUBJECT: GRB 250702A: Fermi GBM Final Real-time Localization DATE: 25/07/02 10:04:44 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply(a)GIOC.nsstc.nasa.gov> The Fermi GBM team reports the detection of a likely LONG GRB At 09:54:07 UT on 2 Jul 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 250702A (trigger 773142852.561082 / 250702413). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 317.8, Dec = 48.1 (J2000 degrees, equivalent to J2000 21h 11m, 48d 06'), with a statistical uncertainty of 1.1 degrees. The angle from the Fermi LAT boresight is 56.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250702413/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250702413/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn250702413/… View this GCN Circular online at https://gcn.nasa.gov/circulars/40881. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38924] LIGO/Virgo/KAGRA S250701bq: Identification of a GW compact binary merger candidate
by GCN Circulars 02 Jul '25

02 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40880 SUBJECT: LIGO/Virgo/KAGRA S250701bq: Identification of a GW compact binary merger candidate DATE: 25/07/02 00:04:55 GMT FROM: 이형원 (Hyung) at Inje University <ijhwlee(a)gmail.com> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S250701bq during real-time processing of data from LIGO Livingston Observatory (L1) at 2025-07-01 23:17:46.927 UTC (GPS time: 1435447084.927). The candidate was found by the GstLAL [1] analysis pipeline. S250701bq is an event of interest because its false alarm rate, as estimated by the online analysis, is 4.3e-17 Hz, or about one in 1e9 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S250701bq The classification of the GW signal, in order of descending probability, is BBH (>99%), Terrestrial (<1%), NSBH (<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%. [2] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [2] 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 <1%. The source chirp mass falls with highest probability in the bin (11.0, 22.0) 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,0, an initial localization generated by BAYESTAR [3], distributed via GCN and SCiMMA notices about 23 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [3], distributed via GCN and SCiMMA notices about 4 minutes after the candidate event time. The preferred sky map at this time is bayestar.multiorder.fits,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 24219 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 556 +/- 171 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] 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 [2] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [3] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/40880. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38923] LIGO/Virgo/KAGRA S250701bp: Identification of a GW compact binary merger candidate
by GCN Circulars 01 Jul '25

01 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40879 SUBJECT: LIGO/Virgo/KAGRA S250701bp: Identification of a GW compact binary merger candidate DATE: 25/07/01 21:05:18 GMT FROM: mayara.pacheco(a)inpe.br ////////////////////////////////////////////////////////////////////// TITLE: GCN/LVC NOTICE NOTICE_DATE: Tue 01 Jul 25 20:35:07 UT NOTICE_TYPE: LVC Preliminary TRIGGER_NUM: S250701bp TRIGGER_DATE: 20857 TJD; 182 DOY; 2025/07/01 (yyyy/mm/dd) TRIGGER_TIME: 74080.857846 SOD {20:34:40.857846} UT SEQUENCE_NUM: 1 GROUP_TYPE: 1 = CBC SEARCH_TYPE: 1 = AllSky PIPELINE_TYPE: 4 = gstlal FAR: 7.698e-18 [Hz] (one per 1503440542705.9 days) (one per 4119015185.50 years) PROB_NS: 0.00 [range is 0.0-1.0] PROB_REMNANT: 0.00 [range is 0.0-1.0] PROB_BNS: 0.00 [range is 0.0-1.0] PROB_NSBH: 0.00 [range is 0.0-1.0] PROB_BBH: 1.00 [range is 0.0-1.0] PROB_MassGap: 0.00 [range is 0.0-1.0] PROB_TERRES: 0.00 [range is 0.0-1.0] TRIGGER_ID: 0x10 MISC: 0x1898802 SKYMAP_FITS_URL: https://gracedb.ligo.org/api/superevents/S250701bp/files/bayestar.multiorde… EVENTPAGE_URL: https://gracedb.ligo.org/superevents/S250701bp/view/ COMMENTS: LVC Preliminary Trigger Alert. COMMENTS: This event is an OpenAlert. COMMENTS: LIGO-Livingston Observatory contributed to this candidate event. ////////////////////////////////////////////////////////////////////// TITLE: GCN/LVC NOTICE NOTICE_DATE: Tue 01 Jul 25 20:39:44 UT NOTICE_TYPE: LVC Preliminary TRIGGER_NUM: S250701bp TRIGGER_DATE: 20857 TJD; 182 DOY; 2025/07/01 (yyyy/mm/dd) TRIGGER_TIME: 74080.856200 SOD {20:34:40.856200} UT SEQUENCE_NUM: 2 GROUP_TYPE: 1 = CBC SEARCH_TYPE: 1 = AllSky PIPELINE_TYPE: 4 = gstlal FAR: 3.133e-17 [Hz] (one per 369476020655.3 days) (one per 1012263070.29 years) PROB_NS: 0.00 [range is 0.0-1.0] PROB_REMNANT: 0.00 [range is 0.0-1.0] PROB_BNS: 0.00 [range is 0.0-1.0] PROB_NSBH: 0.00 [range is 0.0-1.0] PROB_BBH: 1.00 [range is 0.0-1.0] PROB_MassGap: 0.00 [range is 0.0-1.0] PROB_TERRES: 0.00 [range is 0.0-1.0] TRIGGER_ID: 0x10 MISC: 0x2898A02 SKYMAP_FITS_URL: https://gracedb.ligo.org/api/superevents/S250701bp/files/bayestar.multiorde… EVENTPAGE_URL: https://gracedb.ligo.org/superevents/S250701bp/view/ COMMENTS: LVC Preliminary Trigger Alert. COMMENTS: This event is an OpenAlert. COMMENTS: LIGO-Livingston Observatory contributed to this candidate event. ////////////////////////////////////////////////////////////////////// TITLE: GCN/LVC NOTICE NOTICE_DATE: Tue 01 Jul 25 20:56:03 UT NOTICE_TYPE: LVC Initial Skymap TRIGGER_NUM: S250701bp TRIGGER_DATE: 20857 TJD; 182 DOY; 2025/07/01 (yyyy/mm/dd) TRIGGER_TIME: 74080.856200 SOD {20:34:40.856200} UT SEQUENCE_NUM: 3 GROUP_TYPE: 1 = CBC SEARCH_TYPE: 1 = AllSky PIPELINE_TYPE: 4 = gstlal FAR: 3.133e-17 [Hz] (one per 369476020655.3 days) (one per 1012263070.29 years) PROB_NS: 0.00 [range is 0.0-1.0] PROB_REMNANT: 0.00 [range is 0.0-1.0] PROB_BNS: 0.00 [range is 0.0-1.0] PROB_NSBH: 0.00 [range is 0.0-1.0] PROB_BBH: 1.00 [range is 0.0-1.0] PROB_MassGap: 0.00 [range is 0.0-1.0] PROB_TERRES: 0.00 [range is 0.0-1.0] TRIGGER_ID: 0x10 MISC: 0x3898A02 SKYMAP_FITS_URL: https://gracedb.ligo.org/api/superevents/S250701bp/files/bayestar.multiorde… EVENTPAGE_URL: https://gracedb.ligo.org/superevents/S250701bp/view/ COMMENTS: LVC Super Initial Skymap -- a location probability map. COMMENTS: This event is an OpenAlert. COMMENTS: LIGO-Livingston Observatory contributed to this candidate event. View this GCN Circular online at https://gcn.nasa.gov/circulars/40879. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 38922] Fermi Gamma-ray Burst Monitor trigger 772838080/250628885 is not a GRB
by GCN Circulars 01 Jul '25

01 Jul '25

TITLE: GCN CIRCULAR NUMBER: 40878 SUBJECT: Fermi Gamma-ray Burst Monitor trigger 772838080/250628885 is not a GRB DATE: 25/07/01 19:38:23 GMT FROM: Vidushi Sharma at NASA GSFC/UMBC <vidushi.sharma(a)nasa.gov> V. Sharma (NASA-GSFC/UMBC) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 772838080/250628885 at 21:14:35.07 UT on 28 June 2025, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is likely due to a SGR." View this GCN Circular online at https://gcn.nasa.gov/circulars/40878. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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