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

[vsnet-grb-info 40682] LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate
by GCN Circulars 08 Nov '25

08 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42619 SUBJECT: LIGO/Virgo/KAGRA S251108dn: Identification of a GW compact binary merger candidate DATE: 25/11/08 11:42:05 GMT FROM: FRANCESCO STOLZI at Unisi <stolzi3(a)unisi.it> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S251108dn during real-time processing of data from LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) at 2025-11-08 10:32:43.578 UTC (GPS time: 1446633181.578). The candidate was found by the Aframe [1], cWB BBH [2], GstLAL [3], MBTA [4], PyCBC Live [5], and SPIIR [6] analysis pipelines. S251108dn is an event of interest because its false alarm rate, as estimated by the online analysis, is 9.4e-18 Hz, or about one in 1e10 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S251108dn The classification of the GW signal, in order of descending probability, is BBH (>99%), NSBH (<1%), Terrestrial (<1%), or BNS (<1%). Noise transients (glitches) were present in the LIGO Livingston and Virgo detector data within two seconds of the event time, which may affect the parameters or the significance of the candidate. 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%. [7] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [7] 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 2%. 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,0, an initial localization generated by BAYESTAR [8], distributed via GCN and SCiMMA notices about 26 seconds after the candidate event time. * bayestar.multiorder.fits,1, an initial localization generated by BAYESTAR [8], 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,1. For the bayestar.multiorder.fits,1 sky map, the 90% credible region is 697 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 1165 +/- 309 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] Marx et al. PRD 111, 042010 (2025) doi:10.1103/PhysRevD.111.042010 [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] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [7] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [8] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/42619. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40681] The EP-WXT trigger 01709248051 is likely a flaring star
by GCN Circulars 08 Nov '25

08 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42618 SUBJECT: The EP-WXT trigger 01709248051 is likely a flaring star DATE: 25/11/08 01:10:53 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> Y. H. Cheng (YNU), C. Y. Dai (NJU), R. D. Liang, W. Chen, H. Sun (NAO,CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709248051 at the time of 2025-11-08T00:00:49, is likely a stellar flare associated with the High Proper Motion Star [GBA2007] 680. The estimated flux of the flare is around 6 x 10^(-11) erg/s/cm^2 in 0.5-4 keV, corresponding to an X-ray luminosity of around 5.1 x 10^(31) erg/s. 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/42618. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40680] SVOM GRB251106.83: Global MASTER-Net observations report
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42617 SUBJECT: SVOM GRB251106.83: Global MASTER-Net observations report DATE: 25/11/07 19:56:30 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-Kislovodsk robotic telescope [1] located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the SVOM GRB251106.83 (trigger No 1762458982,15h 39m 01.49s , +63d 21m 52.9s, R=0.1547) errorbox 57 sec after notice time and 1565 sec after trigger time at 2025-11-06 20:22:27 UT, with upper limit up to 17.9 mag. The observations began at zenith distance = 73 deg. The sun altitude is -62.3 deg. The galactic latitude b = 45 deg., longitude l = 98 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3034620 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 1626 | 2025-11-06 20:22:27 | MASTER-Kislovodsk | (15h 37m 28.85s , +63d 06m 03.4s) | P- | 120 | 15.6 | 1766 | 2025-11-06 20:24:47 | MASTER-Kislovodsk | (15h 37m 29.81s , +63d 05m 56.6s) | P- | 120 | 15.6 | 1766 | 2025-11-06 20:24:47 | MASTER-Kislovodsk | (15h 37m 42.69s , +63d 28m 24.2s) | P| | 120 | 17.2 | 1905 | 2025-11-06 20:27:07 | MASTER-Kislovodsk | (15h 37m 30.71s , +63d 05m 51.6s) | P- | 120 | 15.5 | 1905 | 2025-11-06 20:27:07 | MASTER-Kislovodsk | (15h 37m 43.57s , +63d 28m 18.7s) | P| | 120 | 17.3 | 2045 | 2025-11-06 20:29:27 | MASTER-Kislovodsk | (15h 37m 31.56s , +63d 05m 46.7s) | P- | 120 | 15.6 | 2045 | 2025-11-06 20:29:27 | MASTER-Kislovodsk | (15h 37m 44.37s , +63d 28m 13.8s) | P| | 120 | 17.2 | 2155 | 2025-11-06 20:31:47 | MASTER-Kislovodsk | (15h 37m 25.48s , +63d 04m 04.1s) | C | 60 | 17.0 | 2275 | 2025-11-06 20:31:47 | MASTER-Kislovodsk | (15h 37m 25.50s , +63d 04m 04.1s) | C | 300 | 17.5 | Coadd 2155 | 2025-11-06 20:31:47 | MASTER-Kislovodsk | (15h 37m 38.06s , +63d 26m 36.1s) | C | 60 | 17.4 | 2873 | 2025-11-06 20:43:45 | MASTER-Kislovodsk | (15h 36m 59.84s , +63d 06m 24.9s) | C | 60 | 17.0 | 2933 | 2025-11-06 20:43:45 | MASTER-Kislovodsk | (15h 36m 59.83s , +63d 06m 24.9s) | C | 180 | 17.8 | Coadd 2873 | 2025-11-06 20:43:45 | MASTER-Kislovodsk | (15h 37m 12.09s , +63d 29m 02.0s) | C | 60 | 17.4 | 2953 | 2025-11-06 20:45:05 | MASTER-Kislovodsk | (15h 37m 04.06s , +63d 05m 20.5s) | C | 60 | 17.1 | 2953 | 2025-11-06 20:45:05 | MASTER-Kislovodsk | (15h 37m 16.46s , +63d 27m 56.8s) | C | 60 | 17.5 | 3033 | 2025-11-06 20:46:25 | MASTER-Kislovodsk | (15h 36m 58.81s , +63d 04m 17.3s) | C | 60 | 17.0 | 3033 | 2025-11-06 20:46:25 | MASTER-Kislovodsk | (15h 37m 11.34s , +63d 26m 52.9s) | C | 60 | 17.4 | 3143 | 2025-11-06 20:47:45 | MASTER-Kislovodsk | (15h 37m 04.62s , +63d 04m 30.1s) | C | 120 | 17.3 | 3144 | 2025-11-06 20:47:45 | MASTER-Kislovodsk | (15h 37m 17.42s , +63d 27m 05.1s) | C | 120 | 17.4 | 3305 | 2025-11-06 20:50:26 | MASTER-Kislovodsk | (15h 37m 04.51s , +63d 05m 55.6s) | C | 120 | 17.3 | 3305 | 2025-11-06 20:50:26 | MASTER-Kislovodsk | (15h 37m 17.54s , +63d 28m 30.4s) | C | 120 | 17.5 | 3444 | 2025-11-06 20:52:46 | MASTER-Kislovodsk | (15h 37m 05.48s , +63d 04m 10.8s) | C | 120 | 17.2 | 3564 | 2025-11-06 20:52:46 | MASTER-Kislovodsk | (15h 37m 05.48s , +63d 04m 10.8s) | C | 360 | 17.9 | Coadd 3444 | 2025-11-06 20:52:46 | MASTER-Kislovodsk | (15h 37m 18.70s , +63d 26m 45.1s) | C | 120 | 17.5 | 3584 | 2025-11-06 20:55:05 | MASTER-Kislovodsk | (15h 37m 07.60s , +63d 05m 54.6s) | C | 120 | 17.2 | 3584 | 2025-11-06 20:55:05 | MASTER-Kislovodsk | (15h 37m 20.97s , +63d 28m 28.6s) | C | 120 | 17.4 | 3724 | 2025-11-06 20:57:25 | MASTER-Kislovodsk | (15h 37m 04.73s , +63d 05m 01.2s) | C | 120 | 17.2 | 3724 | 2025-11-06 20:57:26 | MASTER-Kislovodsk | (15h 37m 18.15s , +63d 27m 35.0s) | C | 120 | 17.4 | 3864 | 2025-11-06 20:59:45 | MASTER-Kislovodsk | (15h 37m 04.57s , +63d 05m 58.7s) | C | 120 | 17.1 | 3924 | 2025-11-06 20:59:45 | MASTER-Kislovodsk | (15h 37m 04.57s , +63d 05m 58.8s) | C | 240 | 17.5 | Coadd 3864 | 2025-11-06 20:59:45 | MASTER-Kislovodsk | (15h 37m 18.12s , +63d 28m 32.3s) | C | 120 | 17.4 | 3974 | 2025-11-06 21:02:05 | MASTER-Kislovodsk | (15h 37m 10.31s , +63d 04m 57.0s) | C | 60 | 16.8 | 3974 | 2025-11-06 21:02:05 | MASTER-Kislovodsk | (15h 37m 23.89s , +63d 27m 30.6s) | C | 60 | 17.2 | 4054 | 2025-11-06 21:03:25 | MASTER-Kislovodsk | (15h 37m 05.87s , +63d 03m 55.5s) | C | 60 | 16.8 | 4054 | 2025-11-06 21:03:25 | MASTER-Kislovodsk | (15h 37m 19.52s , +63d 26m 29.2s) | C | 60 | 17.2 | 4134 | 2025-11-06 21:04:45 | MASTER-Kislovodsk | (15h 37m 13.13s , +63d 04m 18.9s) | C | 60 | 16.8 | 4194 | 2025-11-06 21:04:45 | MASTER-Kislovodsk | (15h 37m 13.12s , +63d 04m 18.9s) | C | 180 | 17.3 | Coadd 4134 | 2025-11-06 21:04:45 | MASTER-Kislovodsk | (15h 37m 26.81s , +63d 26m 52.7s) | C | 60 | 17.1 | 4214 | 2025-11-06 21:06:05 | MASTER-Kislovodsk | (15h 37m 10.83s , +63d 05m 52.4s) | C | 60 | 16.6 | 4214 | 2025-11-06 21:06:05 | MASTER-Kislovodsk | (15h 37m 24.56s , +63d 28m 26.3s) | C | 60 | 16.9 | 4294 | 2025-11-06 21:07:25 | MASTER-Kislovodsk | (15h 37m 24.19s , +63d 26m 54.6s) | C | 60 | 16.9 | 4294 | 2025-11-06 21:07:25 | MASTER-Kislovodsk | (15h 37m 10.45s , +63d 04m 20.8s) | C | 60 | 16.4 | 4373 | 2025-11-06 21:08:45 | MASTER-Kislovodsk | (15h 37m 28.61s , +63d 28m 10.5s) | C | 60 | 16.8 | 4373 | 2025-11-06 21:08:45 | MASTER-Kislovodsk | (15h 37m 14.90s , +63d 05m 36.8s) | C | 60 | 16.5 | 4433 | 2025-11-06 21:08:45 | MASTER-Kislovodsk | (15h 37m 14.90s , +63d 05m 36.9s) | C | 180 | 17.0 | Coadd 4453 | 2025-11-06 21:10:04 | MASTER-Kislovodsk | (15h 37m 22.44s , +63d 27m 24.6s) | C | 60 | 16.7 | 4453 | 2025-11-06 21:10:04 | MASTER-Kislovodsk | (15h 37m 08.69s , +63d 04m 51.0s) | C | 60 | 16.4 | 4533 | 2025-11-06 21:11:24 | MASTER-Kislovodsk | (15h 37m 24.05s , +63d 28m 23.8s) | C | 60 | 16.7 | 4533 | 2025-11-06 21:11:24 | MASTER-Kislovodsk | (15h 37m 10.40s , +63d 05m 50.5s) | C | 60 | 16.3 | 4718 | 2025-11-06 21:14:29 | MASTER-Kislovodsk | (15h 37m 24.27s , +63d 28m 40.2s) | C | 60 | 16.6 | 4718 | 2025-11-06 21:14:29 | MASTER-Kislovodsk | (15h 37m 08.78s , +63d 05m 48.3s) | C | 60 | 16.3 | 4778 | 2025-11-06 21:14:29 | MASTER-Kislovodsk | (15h 37m 08.78s , +63d 05m 48.4s) | C | 180 | 17.0 | Coadd 4797 | 2025-11-06 21:15:49 | MASTER-Kislovodsk | (15h 37m 30.85s , +63d 27m 38.6s) | C | 60 | 16.6 | 4797 | 2025-11-06 21:15:49 | MASTER-Kislovodsk | (15h 37m 15.47s , +63d 04m 46.6s) | C | 60 | 16.2 | 4877 | 2025-11-06 21:17:09 | MASTER-Kislovodsk | (15h 37m 09.03s , +63d 03m 45.3s) | C | 60 | 16.1 | 4877 | 2025-11-06 21:17:09 | MASTER-Kislovodsk | (15h 37m 24.31s , +63d 26m 37.5s) | C | 60 | 16.4 | 4957 | 2025-11-06 21:18:28 | MASTER-Kislovodsk | (15h 37m 31.56s , +63d 27m 02.7s) | C | 60 | 16.4 | 4957 | 2025-11-06 21:18:28 | MASTER-Kislovodsk | (15h 37m 16.46s , +63d 04m 10.3s) | C | 60 | 16.1 | 5077 | 2025-11-06 21:18:28 | MASTER-Kislovodsk | (15h 37m 16.46s , +63d 04m 10.3s) | C | 300 | 17.1 | Coadd 5067 | 2025-11-06 21:19:48 | MASTER-Kislovodsk | (15h 37m 29.80s , +63d 28m 18.5s) | C | 120 | 16.6 | 5067 | 2025-11-06 21:19:48 | MASTER-Kislovodsk | (15h 37m 14.41s , +63d 05m 26.3s) | C | 120 | 16.5 | 5207 | 2025-11-06 21:22:09 | MASTER-Kislovodsk | (15h 37m 30.85s , +63d 27m 02.1s) | C | 120 | 16.7 | 5208 | 2025-11-06 21:22:09 | MASTER-Kislovodsk | (15h 37m 15.48s , +63d 04m 10.2s) | C | 120 | 16.5 | 5347 | 2025-11-06 21:24:28 | MASTER-Kislovodsk | (15h 37m 35.95s , +63d 28m 23.2s) | C | 120 | 16.8 | 5347 | 2025-11-06 21:24:28 | MASTER-Kislovodsk | (15h 37m 20.33s , +63d 05m 31.7s) | C | 120 | 16.6 | 5467 | 2025-11-06 21:24:28 | MASTER-Kislovodsk | (15h 37m 20.33s , +63d 05m 31.7s) | C | 360 | 17.3 | Coadd 5487 | 2025-11-06 21:26:48 | MASTER-Kislovodsk | (15h 37m 30.28s , +63d 27m 30.2s) | C | 120 | 17.0 | 5487 | 2025-11-06 21:26:48 | MASTER-Kislovodsk | (15h 37m 14.65s , +63d 04m 38.6s) | C | 120 | 16.7 | 5627 | 2025-11-06 21:29:08 | MASTER-Kislovodsk | (15h 37m 30.44s , +63d 28m 29.3s) | C | 120 | 17.0 | 5627 | 2025-11-06 21:29:08 | MASTER-Kislovodsk | (15h 37m 14.73s , +63d 05m 38.3s) | C | 120 | 16.8 | 5767 | 2025-11-06 21:31:29 | MASTER-Kislovodsk | (15h 37m 22.89s , +63d 04m 37.5s) | C | 120 | 16.9 | 5887 | 2025-11-06 21:31:29 | MASTER-Kislovodsk | (15h 37m 22.90s , +63d 04m 37.6s) | C | 360 | 17.5 | Coadd 5767 | 2025-11-06 21:31:29 | MASTER-Kislovodsk | (15h 37m 38.60s , +63d 27m 28.5s) | C | 120 | 17.3 | 5907 | 2025-11-06 21:33:48 | MASTER-Kislovodsk | (15h 37m 34.50s , +63d 26m 28.0s) | C | 120 | 17.1 | 5907 | 2025-11-06 21:33:48 | MASTER-Kislovodsk | (15h 37m 18.97s , +63d 03m 36.8s) | C | 120 | 16.9 | 6047 | 2025-11-06 21:36:08 | MASTER-Kislovodsk | (15h 37m 41.42s , +63d 26m 50.4s) | C | 120 | 17.1 | 6047 | 2025-11-06 21:36:08 | MASTER-Kislovodsk | (15h 37m 25.84s , +63d 03m 59.8s) | C | 120 | 16.9 | 6187 | 2025-11-06 21:38:28 | MASTER-Kislovodsk | (15h 37m 39.82s , +63d 28m 06.3s) | C | 120 | 17.1 | 6187 | 2025-11-06 21:38:28 | MASTER-Kislovodsk | (15h 37m 24.04s , +63d 05m 16.2s) | C | 120 | 16.9 | 6307 | 2025-11-06 21:38:28 | MASTER-Kislovodsk | (15h 37m 24.05s , +63d 05m 16.2s) | C | 360 | 17.6 | Coadd 6326 | 2025-11-06 21:40:48 | MASTER-Kislovodsk | (15h 37m 24.02s , +63d 03m 41.3s) | C | 120 | 16.9 | 6326 | 2025-11-06 21:40:48 | MASTER-Kislovodsk | (15h 37m 40.06s , +63d 26m 31.0s) | C | 120 | 17.0 | 6466 | 2025-11-06 21:43:07 | MASTER-Kislovodsk | (15h 37m 44.13s , +63d 27m 56.6s) | C | 120 | 17.0 | 6466 | 2025-11-06 21:43:07 | MASTER-Kislovodsk | (15h 37m 27.84s , +63d 05m 06.8s) | C | 120 | 17.0 | 6606 | 2025-11-06 21:45:27 | MASTER-Kislovodsk | (15h 36m 43.61s , +62d 51m 28.9s) | C | 120 | 16.5 | 6606 | 2025-11-06 21:45:27 | MASTER-Kislovodsk | (15h 36m 34.62s , +63d 14m 55.2s) | C | 120 | 16.4 | 6746 | 2025-11-06 21:47:47 | MASTER-Kislovodsk | (15h 36m 43.64s , +62d 52m 15.3s) | C | 120 | 17.0 | 6746 | 2025-11-06 21:47:47 | MASTER-Kislovodsk | (15h 36m 34.72s , +63d 15m 41.8s) | C | 120 | 16.8 | 6886 | 2025-11-06 21:50:07 | MASTER-Kislovodsk | (15h 36m 52.34s , +62d 51m 06.6s) | C | 120 | 17.1 | 6886 | 2025-11-06 21:50:07 | MASTER-Kislovodsk | (15h 36m 43.50s , +63d 14m 32.6s) | C | 120 | 16.9 | 7026 | 2025-11-06 21:52:27 | MASTER-Kislovodsk | (15h 36m 46.55s , +62d 50m 00.4s) | C | 120 | 17.1 | 7026 | 2025-11-06 21:52:27 | MASTER-Kislovodsk | (15h 36m 37.62s , +63d 13m 26.3s) | C | 120 | 16.9 | 7146 | 2025-11-06 21:52:27 | MASTER-Kislovodsk | (15h 36m 37.62s , +63d 13m 26.3s) | C | 360 | 17.6 | Coadd 7166 | 2025-11-06 21:54:47 | MASTER-Kislovodsk | (15h 36m 53.63s , +62d 50m 22.6s) | C | 120 | 17.1 | 7166 | 2025-11-06 21:54:47 | MASTER-Kislovodsk | (15h 36m 44.73s , +63d 13m 48.7s) | C | 120 | 16.9 | 7306 | 2025-11-06 21:57:07 | MASTER-Kislovodsk | (15h 36m 43.81s , +63d 14m 57.1s) | C | 120 | 16.9 | 7306 | 2025-11-06 21:57:07 | MASTER-Kislovodsk | (15h 36m 52.47s , +62d 51m 30.6s) | C | 120 | 17.4 | 7446 | 2025-11-06 21:59:27 | MASTER-Kislovodsk | (15h 36m 53.33s , +62d 50m 03.7s) | C | 120 | 17.4 | 7446 | 2025-11-06 21:59:27 | MASTER-Kislovodsk | (15h 36m 44.93s , +63d 13m 30.7s) | C | 120 | 16.9 | 7506 | 2025-11-06 21:59:27 | MASTER-Kislovodsk | (15h 36m 44.93s , +63d 13m 30.7s) | C | 240 | 17.4 | Coadd 7555 | 2025-11-06 22:01:47 | MASTER-Kislovodsk | (15h 36m 57.12s , +62d 51m 25.2s) | C | 60 | 17.1 | 7555 | 2025-11-06 22:01:47 | MASTER-Kislovodsk | (15h 36m 48.66s , +63d 14m 52.3s) | C | 60 | 16.8 | 7635 | 2025-11-06 22:03:07 | MASTER-Kislovodsk | (15h 36m 50.86s , +62d 50m 51.1s) | C | 60 | 17.1 | 7635 | 2025-11-06 22:03:07 | MASTER-Kislovodsk | (15h 36m 42.49s , +63d 14m 18.3s) | C | 60 | 16.7 | 7715 | 2025-11-06 22:04:26 | MASTER-Kislovodsk | (15h 36m 52.49s , +62d 51m 51.8s) | C | 60 | 17.1 | 7715 | 2025-11-06 22:04:26 | MASTER-Kislovodsk | (15h 36m 44.22s , +63d 15m 18.9s) | C | 60 | 16.7 | 7775 | 2025-11-06 22:04:26 | MASTER-Kislovodsk | (15h 36m 44.21s , +63d 15m 18.9s) | C | 180 | 17.4 | Coadd 7795 | 2025-11-06 22:05:46 | MASTER-Kislovodsk | (15h 36m 50.63s , +63d 14m 18.7s) | C | 60 | 16.8 | 7795 | 2025-11-06 22:05:46 | MASTER-Kislovodsk | (15h 36m 58.82s , +62d 50m 51.4s) | C | 60 | 17.1 | 7874 | 2025-11-06 22:07:05 | MASTER-Kislovodsk | (15h 36m 53.69s , +62d 49m 51.8s) | C | 60 | 17.1 | 7874 | 2025-11-06 22:07:05 | MASTER-Kislovodsk | (15h 36m 45.62s , +63d 13m 19.1s) | C | 60 | 16.6 | 7954 | 2025-11-06 22:08:25 | MASTER-Kislovodsk | (15h 36m 51.15s , +63d 13m 49.4s) | C | 60 | 16.6 | 8014 | 2025-11-06 22:08:25 | MASTER-Kislovodsk | (15h 36m 51.15s , +63d 13m 49.3s) | C | 180 | 17.4 | Coadd 7954 | 2025-11-06 22:08:25 | MASTER-Kislovodsk | (15h 36m 59.17s , +62d 50m 21.8s) | C | 60 | 17.0 | 8034 | 2025-11-06 22:09:45 | MASTER-Kislovodsk | (15h 36m 48.62s , +63d 15m 03.0s) | C | 60 | 16.7 | 8034 | 2025-11-06 22:09:45 | MASTER-Kislovodsk | (15h 36m 56.65s , +62d 51m 35.8s) | C | 60 | 17.1 | 8113 | 2025-11-06 22:11:05 | MASTER-Kislovodsk | (15h 36m 58.21s , +62d 50m 14.3s) | C | 60 | 16.9 | 8113 | 2025-11-06 22:11:05 | MASTER-Kislovodsk | (15h 36m 50.21s , +63d 13m 41.8s) | C | 60 | 16.6 | 8193 | 2025-11-06 22:12:24 | MASTER-Kislovodsk | (15h 36m 53.00s , +63d 15m 14.2s) | C | 60 | 16.6 | 8253 | 2025-11-06 22:12:24 | MASTER-Kislovodsk | (15h 36m 52.99s , +63d 15m 14.2s) | C | 180 | 17.4 | Coadd 8193 | 2025-11-06 22:12:24 | MASTER-Kislovodsk | (15h 37m 00.97s , +62d 51m 46.9s) | C | 60 | 16.9 | 8273 | 2025-11-06 22:13:44 | MASTER-Kislovodsk | (15h 36m 47.55s , +63d 14m 22.9s) | C | 60 | 16.5 | 8273 | 2025-11-06 22:13:44 | MASTER-Kislovodsk | (15h 36m 55.50s , +62d 50m 55.9s) | C | 60 | 16.9 | 8353 | 2025-11-06 22:15:04 | MASTER-Kislovodsk | (15h 36m 47.15s , +63d 15m 23.3s) | C | 60 | 16.5 | 8353 | 2025-11-06 22:15:04 | MASTER-Kislovodsk | (15h 36m 55.10s , +62d 51m 56.7s) | C | 60 | 16.8 | 8433 | 2025-11-06 22:16:24 | MASTER-Kislovodsk | (15h 36m 53.72s , +63d 14m 23.2s) | C | 60 | 16.4 | 8433 | 2025-11-06 22:16:24 | MASTER-Kislovodsk | (15h 37m 01.82s , +62d 50m 56.9s) | C | 60 | 16.8 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. [1] - V.M. Lipunov, V.G. Kornilov, E.S. Gorbovskoy, N.A. Tiurina & A.S.Kuznetsov, 2023, Astronomical Robotic Networks and Operative Multichanel Astrophysics, Lomonosov MSU PRESS, 591pp. http : // www.pereplet.ru/lipunov/625.html View this GCN Circular online at https://gcn.nasa.gov/circulars/42617. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40679] LIGO/Virgo/KAGRA S251105aj: Updated Sky localization
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42616 SUBJECT: LIGO/Virgo/KAGRA S251105aj: Updated Sky localization DATE: 25/11/07 17:23:04 GMT FROM: Lorenzo Pompili at Max Planck Institute for Gravitational Physics <lorenzo.pompili(a)aei.mpg.de> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S251105aj (GCN Circular 42587). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN and SCiMMA notices, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S251105aj For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 376 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2483 +/- 735 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] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 View this GCN Circular online at https://gcn.nasa.gov/circulars/42616. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40678] LIGO/Virgo/KAGRA S251103f: Updated Sky localization
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42615 SUBJECT: LIGO/Virgo/KAGRA S251103f: Updated Sky localization DATE: 25/11/07 17:19:59 GMT FROM: Lorenzo Pompili at Max Planck Institute for Gravitational Physics <lorenzo.pompili(a)aei.mpg.de> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We have conducted further analysis of the LIGO Hanford Observatory (H1), LIGO Livingston Observatory (L1), and Virgo Observatory (V1) data around the time of the compact binary merger (CBC) candidate S251103f (GCN Circular 42564). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,0, distributed via GCN and SCiMMA notices, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S251103f For the Bilby.multiorder.fits,0 sky map, the 90% credible region is 757 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2158 +/- 537 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] Ashton et al. ApJS 241, 27 (2019) doi:10.3847/1538-4365/ab06fc and Morisaki et al. PRD 108, 123040 (2023) doi:10.1103/PhysRevD.108.123040 View this GCN Circular online at https://gcn.nasa.gov/circulars/42615. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40677] IPN triangulation of GRB 251105B (possible sGRB with EE)
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42614 SUBJECT: IPN triangulation of GRB 251105B (possible sGRB with EE) DATE: 25/11/07 15:12:08 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, and T. Cline on behalf of the Konus-Wind team, Y. Zhang, C. Wang, S. Xiong, J. Wei, and B. Cordier on behalf of the SVOM-GRM team, A. Goldstein, M. S. Briggs, C. Wilson-Hodge, and E. Burns on behalf of the Fermi GBM team, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The possible short-duration GRB with extended emission GRB 251105B (SVOM-GRM detection: Wang et al., GCN 42586; Fermi-GBM detection: Hamburg eat al., GCN 42589; AstroSat-CZTI detection: Harsha et al., GCN 42591) was detected by SVOM (GRM), Konus-Wind, Fermi (GBM), AstroSat (CZTI), and Mars-Odyssey (HEND) at about 3514 s UT (00:58:34). We have triangulated it to a preliminary, 3 sigma error box whose coordinates are: --------------------------------------------- RA(2000), deg Dec(2000), deg --------------------------------------------- Center: 277.814 (18h 31m 15s) +9.028 ( +9d 01' 39") Corners: 277.022 (18h 28m 05s) +9.993 ( +9d 59' 36") 277.294 (18h 29m 11s) +9.729 ( +9d 43' 46") 278.607 (18h 34m 26s) +8.012 ( +8d 00' 43") 278.333 (18h 33m 20s) +8.303 ( +8d 18' 10") --------------------------------------------- The error box area is 362 sq. arcmin, and its maximum dimension is 2.5 deg (the minimum one is 3 arcmin). The Sun distance was 62 deg. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB251105_T03511/IPN The HEALPix triangulation map is the multi-order HEALPix in units of probability density. The Konus-Wind time history and spectrum will be given in a forthcoming GCN Circular. View this GCN Circular online at https://gcn.nasa.gov/circulars/42614. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40676] GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42613 SUBJECT: GRB 251106A: SVOM/COLIBRÍ (FM-GFT) fading of the optical counterpart DATE: 25/11/07 14:32:43 GMT FROM: F. Fortin at IRAP <ffortin.sci.edu(a)gmail.com> Francis Fortin (IRAP), Camila Angulo (UNAM), Jean-Luc Atteia (IRAP), Benjamin Schneider (LAM), Alan M. Watson (UNAM), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Dalya Akl (NYUAD), Sarah Antier (IJCLAB), Rosa L. Becerra (UNAM), Nathaniel R. Butler (ASU), Damien Dornic (CPPM), Jean-Grégoire Ducoin (CPPM), Leonardo García García (UNAM), Ramandeep Gill (UNAM), Noémie Globus (UNAM), Kin Ocelotl López (UNAM), Diego López-Cámara (UNAM), Francesco Magnani (CPPM), Enrique Moreno Méndez (UNAM), Margarita Pereyra (UNAM), Ny Avo Rakotondrainibe (LAM), Fredd Sánchez Álvarez (UNAM), and Antonio de Ugarte Postigo (LAM) report: We imaged the field of the SVOM GRB 251106A (Antier et al., GCN Circ. 42605) using the DDRAGO wide-field imager on the SVOM/COLIBRÍ (FM-GFT) telescope. We observed a second epoch from 2025-11-07 12:34 to 12:50 UTC (from 16.63 to 16.89 hours after the trigger) and obtained an additional 16 minutes of exposure in the r filter at high airmass (3 to 3.5). The photometry was calibrated using nearby stars from the PanSTARRS DR1 catalog, is in the AB system, and is not corrected for Galactic extinction. We detect the optical counterpart we previously reported (Angulo et al, GCN Circ. 42607) at the following preliminary magnitude: r = 21.85 +/- 0.13 Our photometry shows clear fading with respect to our earlier epoch, confirming that this is the optical counterpart of the GRB. We note that the position of the afterglow optical counterpart is coincident with a faint source in the Legacy Survey (Dey et al. 2019) at r = 22.56 +/- 0.17, which could be the host galaxy of the GRB. We thank the staff of the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir and the COLIBRÍ and DDRAGO engineering teams. COLIBRÍ is an astronomical observatory developed and operated jointly by France (AMU, CNES and CNRS) and Mexico (UNAM and SECIHTI). It is located at the Observatorio Astronómico Nacional on the Sierra de San Pedro Mártir, Baja California, Mexico. View this GCN Circular online at https://gcn.nasa.gov/circulars/42613. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40675] GRB 251106B: SVOM/GRM observation of a short burst
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42612 SUBJECT: GRB 251106B: SVOM/GRM observation of a short burst DATE: 25/11/07 10:13:32 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: Feliu Lacreu (IAP) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by a burst GRB 251106B (SVOM trigger reference: sb25110603) at 2025-11-06T18:14:44.300 UTC (T0). With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multiple spikes with a T90 of 1.3+0.5/-0.3 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251106B.png The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. GRM is developed by the Institute of High Energy Physics (IHEP) of CAS. The SVOM point of contact for this burst is: Chen-Wei Wang (IHEP)(cwwang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/42612. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40674] GRB 251106A: Swift-XRT afterglow detection
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42611 SUBJECT: GRB 251106A: Swift-XRT afterglow detection DATE: 25/11/07 10:12:12 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> A. D'Ai (INAF-IASFPA), S. Campana (INAF-OAB), J.A. Kennea (PSU), D.N. Burrows (PSU), S. Lanava (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAR) and P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: Swift-XRT has performed follow-up observations of GRB 251106A. We searched for X-ray sources in 2.0 ks of Photon Counting (PC) mode data. The total exposure at the position of the afterglow (see below) is 2.0 ks, obtained between T0+4.0 ks and T0+9.9 ks. Three uncatalogued X-ray sources are detected, of which one ("Source 1") is above the RASS 3-sigma upper limit at this position, and is therefore likely the GRB afterglow. Using 2020 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 234.46260, +63.36779 which is equivalent to: RA (J2000): 15h 37m 51.02s Dec(J2000): +63d 22' 04.0" with an uncertainty of 2.6 arcsec (radius, 90% confidence). This position is consistent with the optical afterglow candidate identified by Angulo et al. (GCN 42607). The light curve can be modelled with a power-law decay with a decay index of alpha=0.87 (+0.33, -0.29). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.96 (+0.23, -0.22). The best-fitting absorption column is 1.1 (+0.6, -0.5) x 10^21 cm^-2, in excess of the Galactic value of 1.7 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.2 x 10^-11 (3.9 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.1 (+0.6, -0.5) x 10^21 cm^-2 Galactic foreground: 1.7 x 10^20 cm^-2 Excess significance: 2.8 sigma Photon index: 1.96 (+0.23, -0.22) If the light curve continues to decay with a power-law decay index of 0.87, the count rate at T+24 hours will be 0.038 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-12 (1.5 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at https://www.swift.ac.uk/xrt_products/03000182. The results of the full analysis of the XRT observations are available at https://www.swift.ac.uk/SVOM/SVOM_FIELD00048. This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42611. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40673] GRB 251106A: Kilonova-Catcher optical upper limit
by GCN Circulars 07 Nov '25

07 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42610 SUBJECT: GRB 251106A: Kilonova-Catcher optical upper limit DATE: 25/11/07 08:48:49 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> M. Freeberg (KNC), D. Turpin (CEA-Saclay/Irfu), C. Andrade(UMN), S. Antier (OCA/IJCLab), M. Coughlin (UMN), S. Karpov (FZU), P. Hello (IJCLAB), M. Pillas (IAP) on behalf of the GRANDMA/Kilonova-Catcher collaboration: We observed the field of GRB 251106A detected by SVOM (Antier et al., GCN 42605), Swift/BAT-GUANO (Delaunay et al., GCN 42608) and Fermi/GBM subthreshold (Godwin et al., GCN 42608) with the GRANDMA citizen science project Kilonova-catcher (KNC). Our observations were performed with a TEC160FL telescope operated by M. Freeberg. Our observations started at TGRB+5.4hr and were taken with sdss ri filters. In our stacked frames, subtracted from the PanSTARRS DR2 template image, we do not detect the optical counterpart reported by the SVOM/COLIBRI (FM-GFT) (Angulo et al., GCN 42607). We report our follow-up results in the table below: +---------------+-----------+---------+----------------+-------------+ | Tmid-TGRB (hr)| Exp (s) | Filter | Magnitude | Instrument | +===============+===========+=========+================+=============+ | 5.77 | 15 x 180s | r (AB) | 19.7 (5 sigma) | TEC160FL | | 6.58 | 15 x 180s | i(AB) | 20.0 (5 sigma) | TEC160FL | +---------------+-----------+---------+----------------+-------------+ All the data have been reduced by a single data processing pipeline, STDPipe (Karpov et al., 2022). Images obtained with the sloan filters were calibrated using the PanSTARRS DR1 catalog. We use the SkyPortal application (skyportal.io) to monitor our observational campaign (Coughlin et al. 2023). GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr) devoted to the observation of transients in the context of multi-messenger astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/) View this GCN Circular online at https://gcn.nasa.gov/circulars/42610. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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