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

[vsnet-grb-info 40762] LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42698 SUBJECT: LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA DATE: 25/11/15 13:54:03 GMT FROM: Yodgor Rajabov at UBAI <rajabov(a)astrin.uz> O. Burkhonov, Y. Rajabov, Y. Tillayev (UBAI), P. Hello (IJCLAB), A. Klotz (IRAP), M. Coughlin (UMN), S. Karpov (FZU), M. Pillas (IAP), M. Mazek (FZU ), S. Antier (IJCLAB), O. Pyshna (Caltech) on behalf of GRANDMA: We detected transient event 2025adht in RA_J2000=12:00:24.3431, Dec_J2000=+49:02:51.7 reported by (GCN 42677 Anand et al., Franz GCN 42675 et al.,). Observations were carried out at the 1.5-meter telescope Maidanak Observatory by using 4Kx4K SNUCAM CCD. All observations were taken using a Bessel R filter. The observations started at 2025-11-15T00:13:15 UTC and ended at 2025-11-15T00:40:17 UTC. A total of 6 CCD images with an exposure of 300 seconds were obtained. Despite the fact that this object is located far from the equator, we checked for the presence of small bodies in this region using the small body database from 14 November 2025. The check was negative. Cross-identification results indicated the same galaxy without any transient events: DSS J120024.56+490254.3, WISEA J120024.53+490254.1, and GALEXASC J120024.49+490252.9. We analyzed our data using our standard pipeline and with STDWeb/STDPipe (Karpov, 2025). We present stacked results after galaxy soustraction. MJD | DATE-OBS | MAG |M_ERR|U.L.|FILTER| Telescope| MAG system -------------------------------------------------------------------------------------- 60994.00920139 | 2025-11-15 00:29 | 21.54|0.1|22.10|R|UBAI/AZT-22|Vega, Gaia DR3 Which has an equivalent using PS1 of 21.64+/- 0.1 in sdssr using PS1 (color term 0.13). More observations are planned. 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/) Maidanak astronomical observatory (MAO) is an observational facility of the Ulugh Beg Astronomical Institute (UBAI), Uzbekistan Academy of Sciences (http://maidanak.uz/) View this GCN Circular online at https://gcn.nasa.gov/circulars/42698. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40761] GRB 251115A: Tiled Swift observations
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42697 SUBJECT: GRB 251115A: Tiled Swift observations DATE: 25/11/15 13:11:54 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/LAT GRB 251115A. Automated analysis of the XRT data will be presented online at https://www.swift.ac.uk/xrt_products/TILED_GRB00140 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/LAT 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/42697. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40760] GRB 251115A: Fermi-LAT detection
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42696 SUBJECT: GRB 251115A: Fermi-LAT detection DATE: 25/11/15 12:51:17 GMT FROM: A. Holzmann Airasca at University of Trento and INFN Bari <a.holzmannairasca(a)unitn.it> E. Bissaldi (Politecnico and INFN Bari), A. Holzmann Airasca (UniTrento and INFN Bari), R. Gupta (NASA GSFC), T. Nymark (KTH), F. Longo (University and INFN, Trieste) and S. Lopez (CNRS / IN2P3) report on behalf of the Fermi-LAT Collaboration: On November 15, 2025, Fermi-LAT detected high-energy emission from GRB 251115A, which was also detected by Fermi-GBM (trigger 784869607 / 251115139, GCN 42692) and Global MASTER (GCN 42694). The best LAT on-ground location is found to be: RA, Dec = 330.18, -9.18 (J2000) with an error radius of 0.36 deg (90 % containment, statistical error only). This was 80 deg from the LAT boresight at the time of the GBM trigger (T0 = 03:20:02.67 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 - 600 s after the GBM trigger is (1.04 ± 0.34) E-5 ph/cm2/s. The estimated photon index above 100 MeV is -2.5 ± 0.4. The highest-energy photon is a 1.6 GeV event which is observed ~ 490 seconds after the GBM trigger. A Swift ToO has been approved for this burst. The Fermi-LAT point of contact for this burst is Tanja Kramer Nymark (tanjan(a)kth.se) 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/42696. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40759] GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42695 SUBJECT: GRB 251013C: joint SVOM/ECLAIRs-GRM refined analysis DATE: 25/11/15 11:31:15 GMT FROM: SVOM_group <svomgroup(a)bao.ac.cn> Nicolas Dagoneau (CEA), Chen-Wei Wang (IHEP), Frédéric Piron (LUPM), Jean-Luc Atteia (IRAP) Using the event-by-event data downloaded through the X-band ground station, we report the preliminary ECLAIRs-GRM joint analysis of GRB 251013C (SVOM burst-id sb2525101311, GCN 42222) detected at T0 = 2025-10-13T17:39:42, which was also detected Fermi/GBM (GCN 42259). The refined analysis for ECLAIRs only was reported in GCN 42292. T90s are given in the table below for both ECLAIRs and GRM. | Instrument | Energy Range | T90 (s) | |-----------------|------------------|-----------------| | ECLAIRs | 4–120 keV | 19 (-2 / +5) s | | GRM | 50–300 keV | 13 (-1 / +4) s | The ECLAIRs-GRM joint time-averaged spectrum (T0-0.83 s to T0+17.70 s) in the 8-5000 keV energy range is best fitted by a power-law model with a photon index of 1.55 -0.03/+0.02. With this model, the total 10-1000 keV fluence is (4.58 +/- 0.18)e-06 erg/cm^2. From the likelihood profile of Epeak obtained by iteratively fitting a cutoff power-law model with a frozen Epeak parameter, we derived a 95% confidence level lower limit of approximately 480 keV, which is consistent with the value measured by Fermi (GCN 42259). With a redshift of z = 0.572 (GCN 42227), the burst isotropic energy Eiso (from 1 keV to 10 MeV in its rest frame) is 5.6e51 erg, which makes this GRB consistent with type I GRBs in the 'Amati' relation diagram (Amati et al. 2002). All the quoted errors are at the 68% confidence level. 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. ECLAIRs was developed jointly by CNES, CEA-IRFU, CNRS-IRAP, CNRS-APC. The SVOM/ECLAIRs-GRM point of contact for this burst is: Nicolas Dagoneau (nicolas.dagoneau AT cea.fr). View this GCN Circular online at https://gcn.nasa.gov/circulars/42695. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40758] Fermi GRB 251115A: Global MASTER-Net observations report
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42694 SUBJECT: Fermi GRB 251115A: Global MASTER-Net observations report DATE: 25/11/15 04:30:41 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-OAFA robotic telescope [1] located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 251115A ( Fermi GBM team, GCN 42692) errorbox 41 sec after notice time and 74 sec after trigger time at 2025-11-15 03:21:17 UT, with upper limit up to 20.0 mag. The observations began at zenith distance = 64 deg. The sun altitude is -38.6 deg. The galactic latitude b = -47 deg., longitude l = 59 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3042754 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 80 | 2025-11-15 03:21:17 | MASTER-OAFA | (22h 03m 35.41s , -07d 54m 09.9s) | C | 10 | 18.6 | 101 | 2025-11-15 03:21:33 | MASTER-OAFA | (22h 03m 35.36s , -07d 54m 09.6s) | C | 20 | 19.0 | 141 | 2025-11-15 03:22:09 | MASTER-OAFA | (22h 12m 15.81s , -08d 11m 40.7s) | C | 30 | 19.4 | 178 | 2025-11-15 03:22:45 | MASTER-OAFA | (22h 12m 15.80s , -08d 11m 40.4s) | C | 30 | 19.4 | 219 | 2025-11-15 03:23:21 | MASTER-OAFA | (22h 12m 15.79s , -08d 11m 40.4s) | C | 40 | 19.5 | 270 | 2025-11-15 03:24:07 | MASTER-OAFA | (22h 12m 15.78s , -08d 11m 40.0s) | C | 50 | 19.7 | 331 | 2025-11-15 03:25:03 | MASTER-OAFA | (22h 12m 15.78s , -08d 11m 40.0s) | C | 60 | 19.8 | 658 | 2025-11-15 03:30:00 | MASTER-OAFA | (22h 18m 22.95s , -04d 21m 04.4s) | C | 120 | 20.0 | 794 | 2025-11-15 03:32:06 | MASTER-OAFA | (22h 18m 22.96s , -04d 21m 04.5s) | C | 140 | 20.0 | 955 | 2025-11-15 03:34:32 | MASTER-OAFA | (22h 18m 22.96s , -04d 21m 04.4s) | C | 170 | 20.0 | 1076 | 2025-11-15 03:37:28 | MASTER-OAFA | (22h 18m 22.99s , -04d 21m 04.2s) | C | 60 | 19.5 | 1141 | 2025-11-15 03:38:34 | MASTER-OAFA | (22h 18m 23.03s , -04d 21m 04.4s) | C | 60 | 19.5 | 1207 | 2025-11-15 03:39:39 | MASTER-OAFA | (22h 18m 23.03s , -04d 21m 04.4s) | C | 60 | 19.4 | 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/42694. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40757] LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42693 SUBJECT: LIGO/Virgo/KAGRA S251112cm: NED Galaxies in the 4-Update Localization Volume DATE: 25/11/15 03:46:56 GMT FROM: David Cook at Caltech/IPAC-NED <dcook(a)ipac.caltech.edu> David O. Cook (Caltech/IPAC), Rick Ebert (Caltech/IPAC), George Helou (Caltech/IPAC), Joseph M. Mazzarella (Caltech/IPAC), Marion Schmitz (Caltech/IPAC), and Leo Singer (NASA/GSFC) On behalf of the NASA/IPAC Extragalactic Database (NED) Team. We spatially cross-matched the LVK S251112cm-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023; https://ned.ipac.caltech.edu/NED::LVS/) which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 9047 galaxies within the 90% containment volume, and we list here the top 20 galaxies sorted by the joint probability of the 3D localization and the WISE W1 luminosity (an observable proxy for stellar mass). For the full or top 20 list of galaxies in the 90% volume go either to the NED Gravitational Wave Followup service at https://ned.ipac.caltech.edu/uri/NED::GWF/ or click on the following links: Full List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S251112cm/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S251112cm/4/20 The NED-GWF service provides downloadable galaxy lists and visualizations for candidate host galaxies. For each GW alert, these products are automatically generated and made available within minutes to expedite efficient electromagnetic follow-up observations. The NED top 20 list is sorted by the joint probability of the 3D localization and the WISE W1 luminosity, but users can sort on additional pre-computed prioritization metrics (star formation rate, P_3D * P_SFR; and specific star formation rate, P_3D * P_sSFR; etc.) which are available via downloading the entire galaxy list inside the event's probability volume. | objname| ra| dec|objtype| DistMpc|DistMpc_unc| m_NUV| m_NUV_unc| m_Ks| m_Ks_unc| m_W1| m_W1_unc| P_3D|P_3D_LumW1| |-------------------------|--------------|--------------|-------|-----------|-----------|------------|------------|------------|------------|------------|------------|--------|----------| | IC 1633| 17.48145| -45.93116| G| 96.06| 3.43| null| null| 8.396| 0.025| 8.999| 0.006|8.02e-06| 1.10e-08| | IC 0564| 146.58792| 3.07130| G| 75.75| 2.62| null| null| 10.033| 0.035| 10.010| 0.006|2.41e-05| 8.10e-09| | IC 1464B| 345.79587| -8.98909| G| 105.88| 0.59| null| null| 10.015| 0.036| 9.741| 0.006|8.31e-06| 6.98e-09| |WISEA J100012.04+093856.0| 150.05020| 9.64890| G| 78.82| 0.30| null| null| 11.073| 0.096| 10.233| 0.006|2.04e-05| 6.04e-09| | UGC 05226| 146.51479| 4.40348| G| 66.86| 15.78| 18.763| 0.092| 10.211| 0.041| 10.083| 0.089|2.21e-05| 5.42e-09| | ESO 197- G 021| 31.13585| -52.17213| G| 87.54| 0.39| null| null| 9.099| 0.026| 9.375| 0.006|6.49e-06| 5.21e-09| | MCG -01-24-010| 140.09147| -7.88074| G| 53.94| 2.54| 15.885| 0.007| 10.054| 0.032| 9.821| 0.030|2.49e-05| 5.05e-09| | MRK 0421| 166.11381| 38.20883| G| 85.15| 33.84| null| null| 9.996| 0.029| 9.258| 0.005|5.81e-06| 4.92e-09| | IC 1464A| 345.80030| -8.99285| G| 107.09| 0.04| null| null| 11.963| 0.011| 10.070| 0.006|7.57e-06| 4.81e-09| | NGC 7364| 341.10153| -0.16213| G| 76.48| 8.25| 16.366| 0.001| 9.478| 0.028| 9.218| 0.003|6.74e-06| 4.80e-09| | IC 1471| 347.18676| -12.63948| G| 83.00| 17.58| 17.246| 0.027| 10.334| 0.035| 10.290| 0.006|1.49e-05| 4.63e-09| | ESO 243- G 051| 17.83050| -45.93204| G| 94.78| 0.36| 17.032| 0.008| 10.015| 0.031| 10.036| 0.006|8.85e-06| 4.53e-09| | NGC 2951 NED01| 144.92019| -0.23515| G| 70.23| 0.53| 18.380| 0.003| 10.498| 0.057| 10.537| 0.004|2.33e-05| 4.19e-09| | IC 2471| 141.30071| -6.82994| G| 58.50| 12.39| 18.644| 0.054| 9.949| 0.034| 10.076| 0.006|2.19e-05| 4.12e-09| | NGC 3070| 149.52893| 10.35980| G| 60.25| 5.89| 18.225| 0.068| 9.260| 0.030| 9.503| 0.006|1.21e-05| 4.12e-09| | ESO 197- G 018| 30.62846| -50.93160| G| 110.00| 24.82| null| null| 9.612| 0.028| 9.779| 0.006|4.35e-06| 3.80e-09| | NGC 2951 NED02| 144.91664| -0.23524| G| 71.31| 0.04| 18.383| 0.003| 12.873| 0.052| 10.592| 0.004|2.13e-05| 3.75e-09| | ESO 243- G 045| 17.26888| -45.77349| G| 82.00| 9.44| 18.245| 0.024| 9.713| 0.035| 9.964| 0.006|9.07e-06| 3.71e-09| | IC 0563| 146.58473| 3.04574| G| 57.00| 22.05| 16.948| 0.010| 10.810| 0.054| 10.328| 0.027|2.54e-05| 3.62e-09| | ESO 197- G 010| 28.30237| -49.56039| G| 76.43| 6.54| null| null| 8.882| 0.034| 9.458| 0.006|6.17e-06| 3.50e-09| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S251112cm sorted by the joint probability of 3D position and WISE W1 luminosity (P_3D * P_LumW1). Galaxy is the NED preferred name. RA and Dec are the Equatorial coordinates in degrees (J2000). Objtype is the object type of the galaxy candidate. Distance is the distance to the galaxy in Mpc. m_NUV and mErr_NUV are the apparent magnitude and error from GALEX. m_Ks and mErr_Ks are the apparent magnitude and error from 2MASS. m_W1 and mErr_W1 are the apparent magnitude and error from AllWISE. P_3D is the probability that the galaxy is in the volume given the distance of GW event. P_3D_LumW1 is the joint probability within the volume weighted by the WISE1 luminosity of the galaxy (P_3D * P_LumW1). View this GCN Circular online at https://gcn.nasa.gov/circulars/42693. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40756] GRB 251115A: Fermi GBM Final Real-time Localization
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42692 SUBJECT: GRB 251115A: Fermi GBM Final Real-time Localization DATE: 25/11/15 03:30:39 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 03:20:02 UT on 15 Nov 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251115A (trigger 784869607.66655 / 251115139). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 334.5, Dec = -4.5 (J2000 degrees, equivalent to J2000 22h 18m, -4d 30'), with a statistical uncertainty of 4.1 degrees. The angle from the Fermi LAT boresight is 80.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251115139/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251115139/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251115139/… View this GCN Circular online at https://gcn.nasa.gov/circulars/42692. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40755] LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42691 SUBJECT: LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates DATE: 25/11/15 03:16:35 GMT FROM: Xander J Hall at Carnegie Mellon University <xjh(a)andrew.cmu.edu> Xander J. Hall (CMU), Tomás Cabrera (CMU), Julius Gassert (CMU/LMU), Lei Hu (UPenn), Antonella Palmese (CMU), Brendan O’Connor (CMU), Igor Andreoni (UNC), on behalf of the Gravitational Wave MultiMessenger Astronomy DECam Survey (GW-MMADS) team report: We observed the high probability area of the LVK gravitational wave candidate S251112cm (GCN 42650) using the wide-field Dark Energy Camera (DECam) on the 4m Blanco telescope. Observations started at 2025-11-14 00:03 UTC (Prop ID: 2023B-851374; PI Palmese & Andreoni) and focused on the southern lobe of the Bilby skymap (GCN 42690; 30% of the total posterior probability). We run the SFFT difference imaging (Hu et al. 2022) on the available images, filter out likely stars and moving objects, and then visually inspect the remaining transients. We report on TNS 54 new transients within the observed area, and we report here select transients: | id | AT name | ra | dec | discovery_date (UT) | mag_g | mag_g_err | mag_g-mag_i | NED separation | | ------------------------ | ---------- | ---------- | ---------- | ----------------------- | ------ | ----- | ----- | ----- | | T202511140018095m335115* | AT 2025adjp | 4.539622 | -33.854284 | 2025-11-14 02:08:26.016 | 21.13 | 0.04 | 0.25 | 92.7", 94.5", 94.6" | T202511140030086m410443 | AT 2025adkl | 7.535766 | -41.078709 | 2025-11-14 02:13:43.104 | 20.91 | 0.03 | -0.14 | 90.5" *This transient is within 2' of three NED in-volume galaxies. We note while both of these transients are within 2' of a NED in-volume galaxy (GCN 42653), they are both near galaxies with LS DR9 photo-z > 0.12 which would place them outside of the volume. Further analysis is underway. We thank the CTIO and NOIRLab staff for supporting these observations and the data calibration. View this GCN Circular online at https://gcn.nasa.gov/circulars/42691. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40754] LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate
by GCN Circulars 15 Nov '25

15 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42690 SUBJECT: LIGO/Virgo/KAGRA S251112cm: Updated Sky localization and false alarm rate estimate DATE: 25/11/15 00:41:29 GMT FROM: Colm Talbot at Princeton University <talbotcolm(a)gmail.com> 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 S251112cm (GCN Circular 42650). Parameter estimation has been performed using Bilby [1] and a new sky map, Bilby.multiorder.fits,1, distributed via GCN and SCiMMA notices, is available for retrieval from the GraceDB event page: https://gracedb.ligo.org/superevents/S251112cm For the Bilby.multiorder.fits,1 sky map, the 90% credible region is 1681 deg2. Marginalized over the whole sky, the a posteriori luminosity distance estimate is 93 +/- 27 Mpc (a posteriori mean +/- standard deviation). The false alarm rate, as estimated by the MBTA SSM analysis pipeline with an updated background model, has been updated to about one in 4 years. The online search for sub-solar-mass regions is covered by two independent pipelines: MBTA SSM and GstLAL SSM [2]. For the parameter space relevant to the present candidate, only MBTA SSM provides online coverage; therefore, the candidate was triggered solely by MBTA SSM. 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 [2] https://emfollow.docs.ligo.org/userguide/analysis/index.html#false-alarm-ra… View this GCN Circular online at https://gcn.nasa.gov/circulars/42690. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40753] GRB 251113A: Glowbug gamma-ray detection
by GCN Circulars 14 Nov '25

14 Nov '25

TITLE: GCN CIRCULAR NUMBER: 42689 SUBJECT: GRB 251113A: Glowbug gamma-ray detection DATE: 25/11/14 22:40:15 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> C.C. Cheung, R. Woolf, M. Kerr, J.E. Grove (NRL), A. Goldstein (USRA), C.A. Wilson-Hodge, D. Kocevski (MSFC), and M.S. Briggs (UAH) report: The Glowbug gamma-ray telescope [1,2,3], operating on the International Space Station, reports the detection of GRB 251113A, which was also detected by Fermi/GBM (GCN 42671, 42672) and AstroSat/CZTI (GCN 42688). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-11-13 17:37:28.512 with a duration of 24.6 s and a total significance of about 82 sigma. The light curve comprises three primary peaks at ~T0+8s, +12s, and +18s. Low-level emission may be present up to ~T0+37s. Note that data from ~T0+22s to T0+26s suffered from deadtime in various detectors. The analysis results presented here are preliminary and use a response function that lacks a detailed characterization of the surrounding passive structure of the ISS. Glowbug is a NASA-funded technology demonstrator for sensitive, low-cost gamma-ray transient telescopes developed, built, and operated by the U.S. Naval Research Laboratory (NRL) with support from the University of Alabama in Huntsville, USRA, and NASA MSFC. It was launched on 2023 March 15 aboard the Department of Defense Space Test Program’s STP-H9 to the ISS and operated until 2024 April when it was put in safe storage on orbit. Glowbug was removed from storage and resumed operation on 2025 September 12. [1] Grove, J.E. et al. 2020, Proc. Yamada Conf. LXXI, arXiv:2009.11959 [2] Woolf, R.S. et al. 2022, Proc. SPIE, 12181, id. 121811O [3] Woolf, R.S. et al. 2024, Proc. SPIE, 13151, id. 1315108 Distribution Statement A: Approved for public release. Distribution is unlimited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42689. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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