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

[vsnet-grb-info 40380] GRB 251014B: PRIME J-band upper limit
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42305 SUBJECT: GRB 251014B: PRIME J-band upper limit DATE: 25/10/16 00:42:42 GMT FROM: N. Passaleva at Sapienza University of Rome <niccolo.passaleva(a)uniroma1.it> J. Durbak (UMD), N. Passaleva (U Rome), O. Guiffreda (UMD), M. El Kabir (U Rome), E. Troja (U Rome), A. S. Kutyrev (NASA/GSFC), S. B. Cenko (NASA/GSFC) Following the Swift/BAT-GUANO (Ronchini et al., GCN 42263) detection of Fermi/GBM-detected event, we observed the transient field in J filter with PRIME. Observations started ~16 hours after the initial Fermi trigger. Using VISTA Kilo-degree Infrared Galaxy (VIKING) Survey nearby stars for preliminary calibration we do not detect any uncatalogued source down to J>21 AB (3-sigma) not corrected for galactic extinction at the position of the candidates reported by Swift/XRT (Lanava et al. GCN 42289), confirming the optical non-detection reported by Yadav et al. (GCN 42287) PRIME is a 1.8m telescope with 1.56 square degree FOV (0.5 arcsec/pixel) located in Sutherland, South Africa at the South African Astronomical Observatory (SAAO) (Kutyrev et al. 2023, Yama et al. 2023, Durbak et al. 2024). We thank the Osaka University observers at PRIME and the staff at SAAO for their support with these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42305. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40379] Upper limits from a search for additional neutrino events in IceCube
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42304 SUBJECT: Upper limits from a search for additional neutrino events in IceCube DATE: 25/10/15 23:27:15 GMT FROM: Yuhua Yao at IceCube/UW-Madison <yyao255(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search [1] for additional track-like muon neutrino events arriving from the direction of IceCube-251014A (https://gcn.nasa.gov/circulars/42277) in a time range of 1000 seconds centered on the alert event time (2025-10-14 18:24:51.580 UTC to 2025-10-14 18:41:31.580 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, zero track-like events are found within the 90% containment region of IceCube-251014A. We report a p-value of 1.00 in this time window. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2dN/dE evaluated at 1 TeV, is 1.4e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-251014A in a 1000 second time window. 90% of events IceCube would detect from a source at this declination with an E^-2.5 spectrum have energies in the approximate energy range between 3e+02 GeV and 1e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2025-10-13 18:33:11.580 UTC to 2025-10-15 18:33:11.580 UTC). In this case, we report a p-value of 1.00, consistent with no significant excess of track events. IceCube’s sensitivity to neutrino point sources with an E^-2.5 spectrum, expressed as E^2 dN/dE evaluated at 1 TeV, is 1.6e-01 GeV cm^-2 within the 90% spatial containment region of IceCube-251014A in a 2 day time window. The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc(a)icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) View this GCN Circular online at https://gcn.nasa.gov/circulars/42304. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40378] IceCube Alert 251014.77: Global MASTER-Net observations report
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42303 SUBJECT: IceCube Alert 251014.77: Global MASTER-Net observations report DATE: 25/10/15 22:39:32 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the IceCube Alert 251014.77 (trigger No 75492250,00h 11m 35.28s , +02d 54m 43.2s, R=0.51) errorbox 1 days 12049 sec after notice time and 1 days 12105 sec after trigger time at 2025-10-15 21:54:57 UT, with upper limit up to 19.5 mag. The observations began at zenith distance = 36 deg. The sun altitude is -48.7 deg. The galactic latitude b = -58 deg., longitude l = 105 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3014752 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 98536 | 2025-10-15 21:54:57 | MASTER-SAAO | (00h 08m 40.80s , +02d 48m 16.0s) | C | 60 | 19.4 | 98536 | 2025-10-15 21:54:57 | MASTER-SAAO | (00h 10m 29.80s , +02d 32m 25.7s) | C | 60 | 19.5 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42303. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40377] Swift GRB251015.60: Global MASTER-Net observations report
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42302 SUBJECT: Swift GRB251015.60: Global MASTER-Net observations report DATE: 25/10/15 22:02:26 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov(a)xray.sai.msu.ru> V.Lipunov, E.Gorbovskoy, A.Kuznetsov, K.Zhirkov, I.Panchenko, N.Tiurina, P.Balanutsa, V.Topolev, D.Vlasenko, G.Antipov, A.Sankovich, Yu.Tselik, Ya.Kechin, V.Senik, A.Chasovnikov, K.Labsina, I. Gorbunov (Lomonosov MSU), O.Gress, N.Budnev (ISU), C.Francile, F. Podesta, R.Podesta, E. Gonzalez (Observatorio Astronomico Felix Aguilar (OAFA), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), A.Sosnovskij (CrAO), A. Gabovich, V.Yurkov (Blagoveschensk Educational StateUniversity), D.Buckley (SAAO), R.Rebolo (The Instituto de Astrofisica de Canarias), L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory) MASTER-SAAO robotic telescope (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB251015.60 (trigger No 1404295,16h 20m 01.68s , -54d 51m 10.8s, R=0.05) errorbox 27211 sec after notice time and 27228 sec after trigger time at 2025-10-15 21:51:12 UT, with upper limit up to 16.1 mag. The observations began at zenith distance = 83 deg. The sun altitude is -48.5 deg. The galactic latitude b = -4 deg., longitude l = 330 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=3015339 We obtain a following upper limits. Tmid-T0 | Site |Filt.| Expt. | Limit| Comment _________|_____________________|_____|_______|______|________ 27319 | MASTER-SAAO | C | 180 | 15.1 | 27319 | MASTER-SAAO | C | 180 | 16.1 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42302. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40376] GRB 251013C: Kilonova-Catcher optical afterglow detection
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42301 SUBJECT: GRB 251013C: Kilonova-Catcher optical afterglow detection DATE: 25/10/15 20:35:57 GMT FROM: Damien Turpin at CEA-Saclay <dturpin-astro(a)hotmail.com> S. Leonini, M. Freeberg, R. Hellot (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 251013C detected by Fermi/GBM (Fermi GBM team, GCN 42221), SVOM/ECLAIRs and GRM (Rakotondrainibe et al., GCN 42223) and AstroSat CZTI (Arya et al., GCN 42246) with the GRANDMA citizen science project Kilonova-catcher (KNC). Our observations were performed with the TEC180FL, iT32 and iT72 telescopes operated by M. Freeberg, the automated and remoted 0.53m Ritchey-Chretien telescope at Montarrenti Observatory (Siena, Italy, IAU code C88) operated by S. Leonini and a CDK17 telescope located at AITP San Pedro Chile Observatory operated by R. Hellot. Our observations started at TGRB+3.0hr and were taken with Clear, sdss gri and Rc Ic filters. In our stacked frames, subtracted from the PanSTARRS DR2 template image, we detect the optical counterpart firstly reported by SVOM/VT (Palmerio et al., GCN 42223) and later confirmed by many other teams. We report part of our follow-up results in the table below: +---------------+----------+------------+----------------+------------------+ | Tmid-TGRB (hr)| Exp (s) | Filter | Magnitude | Instrument | +===============+==========+============+================+==================+ | 3.18 | 30 x 30s | Rc (Vega) | 16.29 +/- 0.04 | Montarrenti Obs. | | 6.47 | 5 x 300s | Rc (Vega) | 17.63 +/- 0.02 | iT72 | | 8.26 | 6 x 300s | r (AB) | 18.24 +/- 0.05 | CDK17 AITP | +---------------+----------+------------+----------------+------------------+ 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. Images obtained with the Johnson-cousins filters were calibrated using the GAIA DR3 synphot 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/42301. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40375] Fermi-LAT Gamma-ray Observations of IceCube-251014A
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42300 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-251014A DATE: 25/10/15 20:30:22 GMT FROM: Leo Pfeiffer at University of Würzburg <pfeiffer.leo(a)gmail.com> L. Pfeiffer (Univ. of Wuerzburg), S. Buson (DESY, Univ. of Wuerzburg) and S. Garrappa (Weizmann Institute of Science) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC251014A neutrino event (GCN 42277) with all-sky survey data from the Large Area Telescope (LAT), on board the Fermi Gamma-ray Space Telescope. The IceCube event was detected on 25-10-14 at 18:33:11.58 UTC (T0) with J2000 position RA = 2.81 (+0.48, -0.49) deg, Decl. = 2.91 (+0.49, -0.49 ) deg 90% PSF containment (J2000). No cataloged gamma-ray sources are found within the 90% IC251014A localization error (4FGL-DR4; The Fourth Fermi-LAT catalog Data Release 4, The Fermi-LAT collaboration 2023, arXiv:2307.12546). We searched for the existence of intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (> 100 MeV) within the IC251014A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC251014A best-fit position, the >100 MeV flux upper limit (95% confidence) is <1.9e-10 ph cm^-2 s^-1 for ~17-years (2008-08-04 / T0), <1.6e-08 (<8.0e-07) ph cm^-2 s^-1 for a 1-month (1-day) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this analysis, the Fermi-LAT contact person is L. Pfeiffer (leonard.pfeiffer at uni-wuerzburg.de). 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/42300. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40374] GRB 251013D: Swift/UVOT Observations
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42299 SUBJECT: GRB 251013D: Swift/UVOT Observations DATE: 25/10/15 20:20:03 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251013D 71 ks after the Fermi/GBM trigger (GCN Circ. 42224; DeLaunay et al., GCN Circ. 42244). We detect an uncatalogued optical source near the position of XRT source #2 (Burrows et al., GCN Circ. 42291). There is no evidence of fading in the UVOT data thus far. The preliminary UVOT position is: RA (J2000) = 03:07:52.73 = 46.96971 (deg.) Dec (J2000) = +08:48:57.4 = 8.81595 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 71081 72734 1622 20.98+/-0.16 white 76655 78444 1758 20.78+/-0.13 white 82245 83695 1423 20.68+/-0.13 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.312 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/42299. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40373] GRB 251013C: Swift ToO observations
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42281 SUBJECT: GRB 251013C: Swift ToO observations DATE: 25/10/15 05:41:19 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: EDIT: This circular was submitted as the result of a system error regarding the follow up ToO observation for this GRB. The correct URL for GRB 251013C products is https://www.swift.ac.uk/xrt_products/01404126 This circular is, nonetheless, an official product of the Swift-XRT team. View this GCN Circular online at https://gcn.nasa.gov/circulars/42281. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40372] GRB 251013D: Fermi GBM Observation
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42280 SUBJECT: GRB 251013D: Fermi GBM Observation DATE: 25/10/15 05:08:37 GMT FROM: Eva MP <eva.palafox(a)gmail.com> E. Palafox (INAOE) and C. Meegan (UAH) report on behalf of the Fermi Gamma-ray Burst Monitor Team: "At 18:17:00.39 UT on 13 October 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251013D (trigger 782072225/251013762). which was also detected by Swift BAT (J. DeLaunay et al. 2025, GCN 42244). The Fermi GBM on-ground location is consistent with the Swift BAT position. The angle from the Fermi LAT boresight is 70 degrees. The GBM light curve consists of a single emission episode with a duration (T90) of about 42 s (50-300 keV). The time-averaged spectrum from T0-2.0 to T0+53.2 s is best fit by a Comptonized function with Epeak = 129 +/- 12 keV, alpha = -0.9 +/- 0.1. A Band function fits equally well with Epeak = 103 +/- 16 and alpha = -0.8 +/- 0.2, and beta -2.3 +/- 0.2. The event fluence (10-1000 keV) in this time interval is (4.4 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+4.9 s in the 10-1000 keV band is 0.83 +/- 0.03 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/" View this GCN Circular online at https://gcn.nasa.gov/circulars/42280. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40371] GRB 251013C: Swift/UVOT Detection
by GCN Circulars 15 Oct '25

15 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42298 SUBJECT: GRB 251013C: Swift/UVOT Detection DATE: 25/10/15 19:54:12 GMT FROM: Mike Siegel at PSU/Swift MOC <mhs18(a)psu.edu> M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 251013C 0.4 ks after the Fermi/SVOM trigger (GCN Circ. 42221, Rakotondrainibe et al., GCN Circ. 42222). A bright source consistent with the XRT position (Evans et al., GCN Circ. 42232) and optical counterpart (Palmerio et al., GCN Circ. 42223, Perez-Garcia et al., GCN Circ. 42225; Konno et al., GCN Circ. 42226; Masi et al., GCN Circ. 42228; Moskvitin, GCN Circ. 42230; Gompertz et al., GCN Circ. 42231; Garnavich, GCN Circ. 42240; Watson et al., GCN Circ. 42241) is detected in the UVOT exposures. The preliminary UVOT position is: RA (J2000) = 23:03:20.55 = 345.83562 (deg.) Dec (J2000) = -00:12:36.9 = -0.21024 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag u 480 5581 1785 15.22+/-0.03 white 129831 141519 2753 21.66+/-0.20 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.045 in the direction of the burst (Schlegel et al. 1998). View this GCN Circular online at https://gcn.nasa.gov/circulars/42298. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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