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

[vsnet-grb-info 40796] GRB 251117A: SVOM/GRM observation of a short burst
by GCN Circulars 18 Nov '25

18 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42731 SUBJECT: GRB 251117A: SVOM/GRM observation of a short burst DATE: 25/11/18 03:43:19 GMT FROM: Yue Wang <m18509381757(a)163.com> SVOM/GRM team: Yue Wang, Chen-Wei Wang, Wen-Jun Tan, Shi-Jie Zheng, Yue Huang, Shao-Lin Xiong, Shuang-Nan Zhang (IHEP) SVOM/ECLAIRs team: Olivier GODET (IRAP), Frédéric Piron (LUPM) Report on behalf of the SVOM team: SVOM/GRM was triggered in-flight by GRB 251117A (SVOM trigger reference: sb25111701) at 2025-11-17T12:19:52.200 (T0), which is also detected by Fermi/GBM (Fermi GBM Team, GCN #42719) and Fermi/LAT (Airasca et. al., GCN #42729) . With the event-by-event data downloaded through the X-band ground station, the GRM light curve shows that this burst consists of multi-peaks with a T90 of 1.2 +1.4/-0.2 s in the 15-5000 keV band. The SVOM/GRM light curve can be found here: https://www.bursthub.cn//admin/static/svgrb251117A.png In addition, the position of this burst, as determined by Fermi/LAT (RA=331.30, Dec = 5.57, GCN #42729), is located at about 39.52 degrees from the SVOM optical axis, which is inside the ECLAIRs field of view. But ECLAIRs was not taking data. With this localization, the time-averaged spectrum from T0-2 to T0+2 s is best fitted by a power law function with an exponential high-energy cutoff. The power law index is -1.05 +0.10/-0.12 and the cutoff energy, parameterized as Epeak, is 1320 +780/-440 keV. The event fluence (10-1000 keV) in this time interval is (2.10 +0.17/-0.16)E-06 erg/cm^2. The localization of GRB 251117A in the 'Amati' relation diagram is shown at: https://www.bursthub.cn//admin/static/svgrb251117A_amati.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/GRM point of contact for this burst is: Yue Wang (IHEP) (yuewang(a)ihep.ac.cn) View this GCN Circular online at https://gcn.nasa.gov/circulars/42731. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40795] GRB 251117A: Tiled Swift observations
by GCN Circulars 18 Nov '25

18 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42730 SUBJECT: GRB 251117A: Tiled Swift observations DATE: 25/11/18 01:52:11 GMT FROM: Phil Evans at U of Leicester <pae9(a)star.le.ac.uk> P. A. Evans (U. Leicester) reports on behalf of the Swift team: Swift has initiated a series of observations, tiled on the sky, of the Fermi/GBM GRB 251117A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/xrt_products/TILED_GRB00141 Any uncatalogued X-ray sources detected in this analysis will be reported on this website and via GCN COUNTERPART notices. The probability of finding serendipitous sources, unrelated to the Fermi/GBM event is high: any X-ray source considered to be a probable afterglow candidate will be reported via a GCN Circular after manual consideration. Details of the XRT automated analysis methods are detailed in Evans et al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8). This circular is an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42730. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40794] GRB 251117A: Fermi-LAT detection
by GCN Circulars 18 Nov '25

18 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42729 SUBJECT: GRB 251117A: Fermi-LAT detection DATE: 25/11/18 00:50:18 GMT FROM: Rahul Gupta at NASA GSFC <rahul.gupta(a)nasa.gov> A. Holzmann Airasca (UniTrento and INFN Bari), S. Lopez (CNRS / IN2P3), N. Di Lalla (Stanford University) and R. Gupta (NASA GSFC) report on behalf of the Fermi-LAT Collaboration: On November 17, 2025, Fermi-LAT detected high-energy emission from GRB 251117A, which was also detected by Fermi-GBM (trigger 785074797 / 251117514, GCN 42719). The best LAT on-ground location is found to be: RA, Dec = 331.30, 5.57 (J2000) with an error radius of 0.72 deg (90 % containment, statistical error only). This was 51 deg from the LAT boresight at the time of the GBM trigger (T0 = 12:19:52.14 UT). The data from the Fermi-LAT shows a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0 - 5 s after the GBM trigger is (3.4 ± 1.4) E-4 ph/cm2/s. The estimated photon index above 100 MeV is -2.8 ± 0.6. The highest-energy photon is a 0.9 GeV event which is observed ~ 2 seconds after the GBM trigger. A Swift ToO has been requested for this burst. The Fermi-LAT point of contact for this burst is Aldana Holzmann Airasca (a.holzmannairasca(a)unitn.it) The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden. View this GCN Circular online at https://gcn.nasa.gov/circulars/42729. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40793] LAT GRB251117.51: Global MASTER-Net observations report
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42728 SUBJECT: LAT GRB251117.51: Global MASTER-Net observations report DATE: 25/11/17 23:11:42 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-Tavrida robotic telescope [1] located in Russia (Lomonosov MSU, SAI Crimea astronomical station) was pointed to the LAT GRB251117.51 (trigger No 785074797,22h 05m 12.00s , +05d 34m 12.0s, R=0.719833) errorbox 11108 sec after trigger time at 2025-11-17 15:25:00 UT, with upper limit up to 16.0 mag. Observations started at twilight. The observations began at zenith distance = 39 deg. The sun altitude is -12.7 deg. MASTER-Kislovodsk robotic telescope located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the LAT GRB251117.51 errorbox 12105 sec after trigger time at 2025-11-17 15:41:37 UT, with upper limit up to 17.0 mag. The observations began at zenith distance = 38 deg. The sun altitude is -21.1 deg. The galactic latitude b = -39 deg., longitude l = 67 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3044995 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 11138 | 2025-11-17 15:25:00 | MASTER-Tavrida | (22h 06m 43.82s , +05d 59m 20.3s) | C | 60 | 15.1 | 11222 | 2025-11-17 15:26:23 | MASTER-Tavrida | (22h 10m 15.32s , +07d 18m 57.3s) | C | 60 | 16.0 | 11379 | 2025-11-17 15:29:01 | MASTER-Tavrida | (22h 03m 42.52s , +04d 40m 48.3s) | C | 60 | 16.0 | 12135 | 2025-11-17 15:41:37 | MASTER-Kislovodsk | (22h 06m 52.64s , +05d 11m 31.5s) | C | 60 | 16.6 | 12215 | 2025-11-17 15:42:57 | MASTER-Kislovodsk | (22h 03m 51.57s , +03d 16m 19.2s) | C | 60 | 16.4 | 12299 | 2025-11-17 15:44:20 | MASTER-Tavrida | (22h 01m 29.12s , +03d 23m 18.8s) | C | 60 | 16.0 | 13003 | 2025-11-17 15:56:04 | MASTER-Tavrida | (21h 59m 50.40s , +07d 17m 56.1s) | C | 60 | 15.8 | 13672 | 2025-11-17 16:07:13 | MASTER-Tavrida | (21h 55m 17.37s , +05d 59m 54.8s) | C | 60 | 16.0 | 13882 | 2025-11-17 16:10:44 | MASTER-Kislovodsk | (21h 56m 10.36s , +07d 02m 54.9s) | C | 60 | 17.0 | 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/42728. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40792] LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42727 SUBJECT: LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate DATE: 25/11/17 22:03:09 GMT FROM: Alicia Calafat <alicia.calafat(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S251117dq during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2025-11-17 21:38:33.119 UTC (GPS time: 1447450731.119). The candidate was found by the Aframe [1], cWB [2], cWB BBH [3], GstLAL [4], MBTA [5], PyCBC Live [6], and SPIIR [7] analysis pipelines. S251117dq is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.9e-15 Hz, or about one in 1e7 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S251117dq 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%. [8] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [8] 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 (22.0, 44.0) 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: * amplfi.multiorder.fits,0, an initial localization generated by AMPLFI [9], distributed via GCN and SCiMMA notices about 19 seconds after the candidate event time. * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [10], 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,0. For the bayestar.multiorder.fits,0 sky map, the 90% credible region is 1701 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2201 +/- 621 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] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [3] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [4] 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 [5] Alléné et al. CQG 42, 105009 (2025) doi:10.1088/1361-6382/add234 [6] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [7] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [8] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [9] Chatterjee et al. MLST 5, 045030 (2024) doi:10.1088/2632-2153/ad8982 [10] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/42727. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40791] LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42727 SUBJECT: LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate DATE: 25/11/17 22:03:09 GMT FROM: Alicia Calafat <alicia.calafat(a)ligo.org> The LIGO Scientific Collaboration, the Virgo Collaboration, and the KAGRA Collaboration report: We identified the compact binary merger candidate S251117dq during real-time processing of data from LIGO Hanford Observatory (H1) and LIGO Livingston Observatory (L1) at 2025-11-17 21:38:33.119 UTC (GPS time: 1447450731.119). The candidate was found by the Aframe [1], cWB [2], cWB BBH [3], GstLAL [4], MBTA [5], PyCBC Live [6], and SPIIR [7] analysis pipelines. S251117dq is an event of interest because its false alarm rate, as estimated by the online analysis, is 5.9e-15 Hz, or about one in 1e7 years. The event's properties can be found at this URL: https://gracedb.ligo.org/superevents/S251117dq 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%. [8] Using the masses and spins inferred from the signal, the probability of matter outside the final compact object (HasRemnant) is <1%. [8] 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 (22.0, 44.0) 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: * amplfi.multiorder.fits,0, an initial localization generated by AMPLFI [9], distributed via GCN and SCiMMA notices about 19 seconds after the candidate event time. * bayestar.multiorder.fits,0, an initial localization generated by BAYESTAR [10], 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,0. For the bayestar.multiorder.fits,0 sky map, the 90% credible region is 1701 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 2201 +/- 621 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] Klimenko et al. PRD 93, 042004 (2016) doi:10.1103/PhysRevD.93.042004 [3] T. Mishra et al. PRD 105, 083018 (2022) doi:10.1103/PhysRevD.105.083018 [4] 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 [5] Alléné et al. CQG 42, 105009 (2025) doi:10.1088/1361-6382/add234 [6] Dal Canton et al. ApJ 923, 254 (2021) doi:10.3847/1538-4357/ac2f9a [7] Chu et al. PRD 105, 024023 (2022) doi:10.1103/PhysRevD.105.024023 [8] Chatterjee et al. ApJ 896, 54 (2020) doi:10.3847/1538-4357/ab8dbe [9] Chatterjee et al. MLST 5, 045030 (2024) doi:10.1088/2632-2153/ad8982 [10] Singer & Price PRD 93, 024013 (2016) doi:10.1103/PhysRevD.93.024013 View this GCN Circular online at https://gcn.nasa.gov/circulars/42727. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40790] GRB 251116C: Swift/BAT arcminute localization of a burst
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42726 SUBJECT: GRB 251116C: Swift/BAT arcminute localization of a burst DATE: 25/11/17 19:29:14 GMT FROM: Jimmy DeLaunay at Penn State <delauj2(a)gmail.com> James DeLaunay (PSU), Samuele Ronchini (GSSI), Aaron Tohuvavohu (Cosmic Frontier), Jamie A. Kennea (PSU), Tyler Parsotan (NASA GSFC) report: Swift/BAT did not localize GRB 251116C onboard (T0: 2025-11-16T15:57:41 UTC, SVOM/ECLAIRS GCN 42703). In a ground search of BAT survey data, the GRB was detected at a S/N of 7.2 in a single 300 s image (14 - 80 keV) starting at ~T0 - 192 s. The BAT position is RA, Dec = 335.3327, -10.3401 deg which is RA(J2000) = 22h 21m 19.9s Dec(J2000) = -10d 20′ 24.4″ with an estimated uncertainty of 3 arcmin radius. Source X1 detected by Swift/XRT (GCN 42721) falls inside this error circle. View this GCN Circular online at https://gcn.nasa.gov/circulars/42726. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40789] LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42725 SUBJECT: LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations DATE: 25/11/17 18:02:48 GMT FROM: Kenta Taguchi <kentagch(a)kusastro.kyoto-u.ac.jp> Kenta Taguchi, Miho Kawabata (Kyoto U.); Ryosuke Itoh (Ibara City); Hiroshi Akitaya, Tomoki Morokuma (ARC/Chiba Tech); Jun Takahashi, Satoshi Honda, Miyako Tozuka, Shigeru Takahashi (Univ. of Hyogo/NHAO); Koji Kawabata, Tatsuya Nakaoka (Hiroshima U.); Haruna Hagio, Ryotaro Kato, Atsuya Ochi, Mahito Sasada, Ichiro Takahashi (Science Tokyo); Nozomu Tominaga, Yousuke Utsumi, Michitoshi Yoshida, Haibin Zhang, Masafumi Niwano, Mitsuru Kokubo, Yuhei Iwata (NAOJ); Masaomi Tanaka (Tohoku University); Yuu Niino, Taiga Sasaoka (U. of Tokyo); Yumiko Oasa, Takahiro Kanai (Saitama Univ.); Yuichiro Sekiguchi (Toho University) on behalf of the J-GEM collaboration We report imaging follow-up observations for the gravitational-wave event S251112cm (GCN 42650). Our observations started at 2025-11-12 19:09:29 UT (MJD=60991.80), approximately 3.8 hours after the event, and ended at 2025-11-17 10:18:47 UT (MJD=60996.43). We conducted galaxy-targeted observations of 135 galaxies (see the table below), selected from the GLADE catalog (v2.4; Dalya et al. 2018) within the probability skymap of S251112cm, using the telescopes and instruments listed below. After screening out known minor planets, we did not find any apparent transient candidates in these galaxies down to the 5-sigma limiting magnitudes in the AB magnitude system summarized below. galid ra dec dist g r R i I z J H Ks NoFilt obsid --------------- -------- -------- ------ ---- ---- ---- ---- ---- ---- ---- ---- ---- ------ ------- GL000835-335128 2.1441 -33.8578 97.4 -- -- 17.2 -- -- -- -- -- -- -- 1 GL094621+030417 146.5879 3.0713 86.9 19.6 18.6 -- 18.8 -- -- -- -- -- 18.3 2,3 GL095807+102135 149.5288 10.3598 77.8 20.4 19.9 19.8 19.8 18.0 -- -- 15.8 -- -- 4,5,2 GL102235+195314 155.6440 19.8871 82.7 19.9 19.6 18.7 19.6 18.0 -- -- -- -- 19.0 5,2,3 GL094620+030244 146.5848 3.0455 87.3 19.6 18.6 -- 18.8 -- -- -- -- -- 18.3 2,3 GL094604+042412 146.5148 4.4033 71.9 18.0 17.1 -- 17.2 -- -- -- -- -- 18.5 2,3 GL093427-023015 143.6119 -2.5041 78.1 19.6 18.6 20.1 18.9 -- -- -- 16.8 -- 14.9 2,3,4 GL100140+104523 150.4186 10.7564 78.3 19.9 19.5 18.6 19.5 17.9 -- -- -- -- 18.6 5,2,3 GL103939+251921 159.9126 25.3226 75.2 19.8 -- 19.9 19.1 -- -- -- 15.8 -- 18.9 2,3,4 GL092022-075250 140.0914 -7.8807 49.6 19.2 18.4 19.6 18.6 -- -- -- 17.2 -- 18.5 2,4,3 GL224424-000943 341.1015 -0.1620 70.1 -- -- 18.2 -- -- -- -- 18.8 -- 19.4 1,3,6 GL094909+022851 147.2866 2.4808 88.5 20.4 19.6 15.3 19.3 15.1 -- -- -- -- 14.5 5,2,3 GL094559+030843 146.4950 3.1453 85.8 19.7 19.0 -- 18.8 -- -- -- -- -- 18.2 2,3 GL102905+221246 157.2692 22.2128 92.9 20.0 19.4 -- 19.2 -- -- -- -- -- 19.1 2,3 GL230311-085921 345.7959 -8.9890 104.2 20.4 19.6 -- 19.8 -- -- -- -- 17.6 19.2 2,3,6 GL094036+033437 145.1516 3.5769 73.2 18.3 17.3 -- 17.5 -- 16.5 -- -- -- -- 7,2 GL234745-280828 356.9380 -28.1410 124.7 18.3 17.6 -- 23.8 -- -- -- -- -- -- 2 GL234045-244137 355.1890 -24.6937 98.5 -- 18.5 -- 19.2 -- -- -- -- -- 18.9 3,2 GL230344-071330 345.9325 -7.2250 74.5 20.2 19.7 18.6 19.9 18.2 18.2 -- -- -- 19.0 2,7,3,5 GL103958+240528 159.9915 24.0912 91.6 19.7 18.8 -- 18.8 -- -- -- -- -- -- 2 GL093941-001406 144.9204 -0.2351 72.2 17.1 16.5 -- 16.4 -- -- -- -- -- 17.8 2,3 GL103130+245210 157.8750 24.8693 90.7 19.6 18.6 -- 18.4 -- -- -- -- -- 18.7 2,3 GL110800+365220 166.9981 36.8722 116.9 20.2 19.4 -- 19.4 -- -- -- -- -- 19.0 2,3 GL234729-280634 356.8690 -28.1093 120.3 18.3 17.6 -- 23.8 -- -- -- -- -- -- 2 GL235137-282154 357.9030 -28.3651 121.0 18.4 18.0 -- -- -- -- -- -- -- 18.6 3,2 GL101229+122237 153.1220 12.3771 79.2 19.7 19.3 -- 19.2 -- -- -- -- -- 18.7 2,3 GL093411+001431 143.5443 0.2420 70.9 20.2 19.7 18.6 19.7 17.9 -- -- 17.8 -- 17.7 5,2,3,4 GL225651-085803 344.2120 -8.9674 72.7 -- -- -- -- -- -- 17.9 17.9 -- 19.0 3,6 GL225542-052943 343.9238 -5.4953 43.8 19.2 -- -- 18.2 -- -- -- -- -- 19.4 2,3 GL104801+281447 162.0045 28.2464 92.0 21.6 21.2 -- 21.2 -- -- -- -- -- 21.1 2,3 GL092514-064300 141.3074 -6.7166 88.7 20.0 19.4 -- 19.4 -- -- -- -- -- 18.9 2,3 GL104437+261054 161.1539 26.1816 90.8 -- -- -- -- -- -- -- -- -- 18.9 3 GL232431-190333 351.1310 -19.0591 110.5 19.9 18.8 -- 18.9 -- -- -- 18.1 18.1 19.0 2,3,6 GL000254-341408 0.7269 -34.2357 98.9 -- -- 16.7 -- 17.2 -- -- -- -- -- 5 GL091049-085331 137.7050 -8.8919 27.7 20.0 19.3 -- 19.4 -- -- -- -- -- 18.7 2,3 GL223407+053413 338.5282 5.5703 65.5 19.9 18.9 -- 19.6 -- -- 17.4 17.9 17.5 -- 2,6 GL235624-312111 359.0995 -31.3532 125.1 -- -- -- -- -- -- -- -- -- 17.9 3 GL104703+263235 161.7609 26.5430 91.8 19.7 -- -- 19.0 -- -- -- -- -- 18.7 2,3 GL225138-053326 342.9087 -5.5573 53.2 19.9 19.4 -- 19.8 -- -- -- -- -- 19.2 2,3 GL225641-072245 344.1724 -7.3790 64.2 19.2 18.1 -- 18.5 -- -- -- -- -- -- 2 GL095230+020916 148.1235 2.1544 72.2 19.6 19.0 -- 18.7 -- -- -- -- -- 18.6 2,3 GL095730+080729 149.3742 8.1246 94.6 -- -- -- -- -- -- -- -- -- 19.0 3 GL103617+265744 159.0691 26.9623 92.1 19.5 19.1 -- 19.0 -- -- -- -- -- 19.1 2,3 GL234743-280838 356.9300 -28.1439 117.6 18.3 17.6 -- 23.8 -- -- -- -- -- -- 2 GL093635+010700 144.1473 1.1165 71.3 19.5 18.6 20.6 18.8 -- -- -- 16.2 -- -- 2,4 GL092056-094336 140.2319 -9.7268 56.4 -- -- -- -- -- -- -- -- -- 18.7 3 GL094617+054231 146.5710 5.7087 44.7 19.4 18.8 19.9 18.7 -- 17.1 -- 15.3 -- -- 7,2,4 GL094541+045631 146.4228 4.9419 54.0 19.9 19.2 -- 19.3 -- 17.9 -- -- -- -- 7,2 GL104245+265038 160.6860 26.8438 87.9 20.1 19.6 -- 19.4 -- -- -- -- -- 18.8 2,3 GL110427+381232 166.1138 38.2089 135.9 -- 18.2 -- 17.9 -- 18.1 -- -- -- 18.5 7,3 GL094901+041811 147.2530 4.3030 88.8 -- -- -- -- -- -- -- -- -- 18.6 3 GL094410+022437 146.0433 2.4103 86.7 20.1 19.3 -- -- -- -- -- -- -- -- 2 GL232149-164309 350.4551 -16.7192 85.6 18.6 17.6 -- 18.0 -- -- -- -- -- 19.0 2,3 GL230658-091710 346.7422 -9.2861 103.7 19.8 18.9 -- 19.1 -- -- -- 17.7 -- 18.8 2,3,6 GL101301+170203 153.2554 17.0342 95.9 19.3 19.0 20.6 18.9 17.2 -- -- 16.0 -- 18.6 5,2,4,3 GL093434+000522 143.6430 0.0894 68.4 19.9 19.5 18.6 19.7 17.9 -- -- -- -- 17.6 5,2,3 GL104827+263502 162.1140 26.5838 88.5 27.3 27.3 -- 27.3 -- -- -- -- -- 27.0 2,3 GL110558+362425 166.4920 36.4070 108.1 20.2 19.8 -- 19.5 -- -- -- -- -- 18.6 2,3 GL225544-062712 343.9352 -6.4533 104.7 19.9 19.2 -- 19.5 -- -- -- -- -- -- 2 GL100135+124554 150.3962 12.7649 91.2 19.8 19.3 -- 19.2 -- -- -- -- -- 18.8 2,3 GL235754-314854 359.4764 -31.8151 126.6 -- -- -- -- -- -- -- -- -- 18.0 3 GL100430+144608 151.1230 14.7690 101.5 19.3 18.6 20.0 18.4 -- -- -- 18.0 -- 14.3 4,2,3 GL100545+101636 151.4356 10.2767 104.9 -- -- -- -- -- -- -- -- -- 18.7 3 GL095757+102556 149.4862 10.4323 76.5 20.3 19.8 19.8 19.7 18.0 -- -- 15.8 -- -- 4,5,2 GL095905+102140 149.7714 10.3611 77.6 18.0 16.7 18.6 -- 18.0 -- -- -- -- -- 5,2 GL110759+352748 166.9957 35.4633 125.8 19.7 19.0 -- 19.0 -- -- -- -- -- 18.4 2,3 GL104739+261746 161.9130 26.2961 91.8 19.1 18.0 -- 18.3 -- -- -- -- -- 18.4 2,3 GL095351+085241 148.4630 8.8781 92.4 19.6 18.7 18.4 18.5 17.6 -- -- -- -- 18.8 2,3,5 GL232338-190035 350.9101 -19.0097 112.2 19.7 18.5 -- 19.1 -- -- -- -- -- 19.2 2,3 GL233923-222956 354.8438 -22.4989 112.9 19.2 18.9 -- 19.2 -- -- -- -- -- -- 2 GL120532+513017 181.3840 51.5047 124.3 20.4 19.7 -- 19.4 -- -- -- -- -- 18.8 2,3 GL110916+360116 167.3172 36.0212 92.7 19.9 19.1 -- 19.3 -- -- -- -- -- 18.1 2,3 GL230009-083953 345.0359 -8.6647 107.0 20.2 19.6 -- 19.6 -- -- -- -- -- -- 2 GL110505+352157 166.2693 35.3657 108.9 20.1 19.4 -- 19.1 -- -- -- -- -- 18.1 2,3 GL104552+255705 161.4677 25.9515 90.5 19.6 18.9 -- 18.5 -- -- -- -- -- 18.2 2,3 GL110955+365648 167.4810 36.9465 132.5 20.6 20.0 -- 19.7 -- -- -- -- -- 19.1 2,3 GL094900+022748 147.2477 2.4633 82.6 -- -- -- -- -- -- -- -- -- 14.5 3 GL102626+173038 156.6065 17.5105 80.7 -- -- -- -- -- -- -- -- -- 18.8 3 GL104607+255417 161.5305 25.9049 92.1 19.6 18.9 -- 18.5 -- -- -- -- -- 18.2 2,3 GL234615-280557 356.5627 -28.0990 121.6 -- 18.5 -- 18.8 -- -- -- -- -- -- 2 GL103139+255902 157.9119 25.9840 91.5 18.9 18.6 -- 18.2 -- 18.0 -- -- -- 19.1 7,2,3 GL102241+205133 155.6709 20.8590 107.4 -- -- -- -- -- -- -- -- -- 19.2 3 GL113253+433054 173.2190 43.5150 106.2 23.4 23.1 -- 19.6 -- -- -- -- -- 21.3 2,3 GL095106+090031 147.7751 9.0085 75.2 20.4 19.8 20.0 19.6 18.1 -- -- 17.7 -- 18.9 5,4,2,3 GL093744+024542 144.4330 2.7616 97.9 20.4 19.5 20.7 19.7 -- -- -- -- -- -- 2,4 GL091711-044508 139.2939 -4.7521 51.0 19.6 19.1 19.6 18.8 -- -- -- 17.4 -- 18.0 2,3,4 GL104642+255554 161.6770 25.9317 89.6 20.0 19.4 -- 19.0 -- -- -- -- -- 18.6 2,3 GL102917+260557 157.3200 26.0991 73.6 17.7 -- -- -- -- -- -- -- -- -- 2 GL110958+370810 167.4932 37.1360 113.7 20.2 -- -- 19.4 -- -- -- -- -- -- 2 GL111208+352707 168.0335 35.4520 108.8 20.2 18.8 -- 19.5 -- -- -- -- -- 17.9 2,3 GL094955+090949 147.4781 9.1637 75.6 18.2 17.3 19.7 17.1 15.5 -- -- 17.8 -- -- 5,2,4 GL100836+181353 152.1515 18.2313 73.9 -- -- 20.0 -- -- -- -- 18.2 -- -- 4 GL093411+001430 143.5440 0.2417 66.7 20.2 19.7 17.4 19.7 17.0 -- -- 17.2 -- 13.9 5,2,3,4 GL130847+621618 197.1938 62.2716 118.2 19.8 19.1 -- 18.8 -- -- -- -- -- 18.0 2,3 GL121329+504429 183.3722 50.7415 134.9 19.7 19.2 -- 19.0 -- -- -- -- -- -- 2 GL110542+350704 166.4263 35.1178 125.8 -- -- -- -- -- -- -- -- -- 17.9 3 GL233707-202747 354.2789 -20.4631 115.3 19.0 17.8 -- 18.2 -- -- -- -- -- -- 2 GL225223+010533 343.0941 1.0926 71.3 20.2 18.9 -- 19.2 -- -- -- -- -- -- 2 GL123208+562816 188.0340 56.4711 66.5 20.4 19.9 -- 22.2 -- -- -- -- -- 19.8 2,3 GL123221+563923 188.0891 56.6564 66.6 -- -- -- -- -- -- -- -- -- 17.9 3 GL120251+483811 180.7111 48.6363 49.4 20.1 19.7 -- 19.8 -- -- -- -- -- 18.2 2,3 GL110841+360940 167.1716 36.1610 121.1 -- -- -- -- -- -- -- -- -- 12.3 3 GL092046-080322 140.1927 -8.0562 85.6 -- -- -- -- -- -- -- -- -- 18.5 3 GL231645-185257 349.1889 -18.8825 109.5 19.2 -- -- 18.4 -- -- -- -- -- -- 2 GL130737+621258 196.9038 62.2160 121.1 20.2 19.7 -- 19.6 -- -- -- -- -- 17.9 2,3 GL104827+263501 162.1137 26.5837 91.4 27.3 27.3 -- 27.3 -- -- -- -- -- -- 2 GL120945+563125 182.4386 56.5235 115.1 -- -- -- -- -- -- -- -- -- 17.8 3 GL231022-084119 347.5910 -8.6886 103.0 18.3 17.2 -- 17.4 -- -- -- -- -- -- 2 GL091906-064215 139.7744 -6.7042 87.6 -- -- -- -- -- -- -- -- -- 17.6 3 GL113906+431450 174.7746 43.2473 106.3 20.4 19.9 -- 19.7 -- -- -- -- -- -- 2 GL123600+541315 189.0006 54.2208 77.6 20.2 19.4 -- 19.6 -- -- -- -- -- -- 2 GL111118+352308 167.8252 35.3855 108.8 20.1 19.3 -- 19.9 -- -- -- -- -- 18.1 2,3 GL225716-105700 344.3147 -10.9499 105.2 19.7 18.4 -- 18.9 -- -- -- -- -- -- 2 GL094953+090545 147.4705 9.0959 81.5 15.9 -- 19.7 -- 15.5 -- -- -- -- -- 5,4 GL114916+460713 177.3185 46.1203 94.5 -- -- -- -- -- -- -- -- -- 18.3 3 GL230009-124828 345.0368 -12.8079 50.6 20.1 19.1 -- 19.3 -- -- -- -- -- -- 2 GL114803+461028 177.0139 46.1746 108.5 -- -- -- -- -- -- -- -- -- 18.3 3 GL111451+353008 168.7137 35.5022 93.5 19.9 19.1 -- 19.2 -- -- -- -- -- 17.9 2,3 GL093745+024450 144.4378 2.7473 101.6 20.4 19.5 -- 19.7 -- -- -- -- -- -- 2 GL104532+240900 161.3845 24.1501 88.9 20.2 19.5 -- 19.0 -- -- -- -- -- -- 2 GL120446+491112 181.1925 49.1865 104.5 -- -- -- -- -- -- -- -- -- 17.9 3 GL111522+353007 168.8413 35.5020 92.4 19.9 19.1 -- 19.2 -- -- -- -- -- 17.9 2,3 GL111507+363224 168.7802 36.5401 107.1 20.2 19.3 -- 19.2 -- -- -- -- -- 18.2 2,3 GL103546+210253 158.9420 21.0481 102.5 17.5 -- 18.8 -- 18.0 -- -- -- -- 18.8 5,3 GL111535+363033 168.8966 36.5092 108.8 20.2 19.3 -- 19.2 -- -- -- -- -- 17.9 2,3 GL232235-130539 350.6470 -13.0941 102.5 19.9 18.9 -- 19.0 -- -- -- -- -- -- 2 GL112646+391558 171.6918 39.2662 90.6 -- -- -- -- -- -- -- -- -- 17.8 3 GL111734+360351 169.3902 36.0641 112.8 19.9 19.3 17.8 19.2 16.9 -- -- -- -- 17.8 2,3,5 GL094937+090019 147.4041 9.0053 75.4 18.9 18.1 15.9 17.8 15.5 -- -- 18.1 -- -- 5,2,4 GL111703+360828 169.2646 36.1411 110.5 20.3 19.6 17.8 19.6 16.9 -- -- -- -- -- 2,5 GL112719+383952 171.8290 38.6645 93.8 20.3 -- -- 19.2 -- -- -- -- -- 17.7 2,3 GL122635+525934 186.6451 52.9929 94.6 -- -- -- -- -- -- -- -- -- 18.2 3 GL112001+360603 170.0025 36.1007 110.3 20.5 19.6 -- 19.5 -- -- -- -- -- -- 2 GL113009+383713 172.5390 38.6204 93.3 -- -- -- -- -- -- -- -- -- 17.8 3 GL232407-115139 351.0290 -11.8607 108.1 19.7 18.6 -- 19.1 -- -- -- -- -- -- 2 References for obsid: 1: BAO101cm: 101 cm telescope at Bisei Astronomical Observatory and CCD optical camera (B, V, Rc, Ic) 2: Seimei-TriCCS: 380 cm Seimei telescope (g, r, i) 3: Kiso Schmidt: 105 cm Schmidt telescope at Kiso Observatory and Tomo-e Gozen 20 deg2 fov camera (no filter) 4: Kanata-HONIR: 150 cm Kanata telescope at Higashi-Hiroshima Observatory and HONIR -- a 2 channel imager (Rc and H or J) (Akitaya et al. 2014, Proc. SPIE 9147, 91474O) 5: MITSuME-Akeno: 50 cm MITSuME telescope at Akeno Observatory and a 3 color imager (g, Rc, Ic); The images were processed in real-time through the MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, 73, 1, 4-24; https://github.com/MNiwano/Eclaire) 6: Nayuta-NIC: 200 cm Nayuta telescope at Nishi-Harima Astronomical Observatory and Nishiharima Infrared Camera, NIC (J, H, Ks) 7: SaCRA-MuSaSHI: 55 cm SaCRA telescope at Saitama University and MuSaSHI (r, i, z) (Oasa et al., 2020, proc. SPIE, 11447, 114475Z) View this GCN Circular online at https://gcn.nasa.gov/circulars/42725. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40788] LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42724 SUBJECT: LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman DATE: 25/11/17 16:41:19 GMT FROM: André Santos at Centro Brasileiro de Pesquisas Físicas (CBPF) <andsouzasanttos(a)gmail.com> A. Santos (CBPF), C. D. Kilpatrick (Northwestern), C. R. Bom (CBPF), L. Santana-Silva (CBPF), P. Darc (CBPF), Gabriel Teixeira (CBPF), C. Mendes de Oliveira (IAG-USP) report on behalf of the STEP-GW collaboration Following the subsolar-mass gravitational-wave candidate S251112cm (GCN 42650, 42690), we conducted optical spectroscopic follow-up of four transients: 2025adiw, 2025adim, 2025adhf, and 2025adjf using the Goodman High-Throughput Spectrograph on the SOAR 4.1 m telescope at Cerro Pachón, Chile. Observations were performed on UT 2025 Nov 17 with the 400 l/mm M1 grating, 2×2 binning. For each source we obtained two 900 s exposures and coadded them for analysis. Each target was submitted for spectrum acquisition using the AEON queue. We classified 2025adim, 2025adiw, and 2025adhf as Type Ia supernovae based on SNID-SAGE spectral matches and identifiable SN Ia features. For 2025adjf, the spectra were heavily contaminated by host-galaxy light, preventing a definitive classification, and we instead report the host galaxy redshift based on nebular emission lines in the extracted spectrum. Our classification and redshift estimates are listed as follows: | AT Name | Classification | redshift | |----------|----------------|----------| | [2025adim](https://www.wis-tns.org/object/2025adim) | SN Ia | 0.091 | | [2025adiw](https://www.wis-tns.org/object/2025adiw) | SN Ia | 0.165 | | [2025adhf](https://www.wis-tns.org/object/2025adhf) | SN Ia | 0.098 | | [2025adjf](https://www.wis-tns.org/object/2025adjf) | - | 0.124 | All classified events are best matched to templates of normal or 91T-like SNe Ia at redshifts inconsistent with the expected distance for S251112cm, and thus are unlikely to be associated with the GW candidate. These results are based on observations obtained through the Astronomical Event Observatory Network (AEON), a joint endeavor of Las Cumbres Observatory and NSF NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the U.S. National Science Foundation. View this GCN Circular online at https://gcn.nasa.gov/circulars/42724. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40787] GRB 251116B: SVOM/VT optical upper limit
by GCN Circulars 17 Nov '25

17 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42723 SUBJECT: GRB 251116B: SVOM/VT optical upper limit DATE: 25/11/17 16:17:41 GMT FROM: Huali Li at at NAOC, SVOM <lhl(a)nao.cas.cn> H. L. Li, L. P. Xin, Y. L. Qiu, C. Wu, Y. N. Ma, Z. H. Yao, Y. Xu, X. H. Han, J. Wang, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, L. Lan, J. R. Xu, J. S. Deng, J. Y. Wei (NAOC), J. Palmerio (CEA), M. Pillas (IAP), M.G. Bernardini (INAF-OAB, LUPM) report on behalf of the SVOM/VT team. SVOM/VT performed ToO observation on GRB 251116B (SVOM burst-id sb25111604, Pillas et al., GCN 42702). The observation started on 2025-11-17T01:05:38 UT (i.e. 9.55 hour post trigger) in VT_B (400nm-650nm) and VT_R (650nm-1000nm) channel simultaneously. Inside the error box of SVOM/ECL (Pillas et al., GCN 42702) and the 6 sources reported by EP-FXT (Li et al., GCN 42709), we did not detect any new uncatalogued sources. Also no significant variation was found for the catalogued sources within EP-FXT's error circles. The 3 sigma upper limit magnitudes are derived as below: Mid time | Band | Exposure Time | 3 sigma upper limit 10.0 hour VT_B 19*70 sec >23.3 mag 10.0 hour VT_R 22*70 sec >23.3 mag Our result is consistent with the LCO's observation (Turpin et al., GCN 42706). 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. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/42723. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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