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[vsnet-grb-info 40350] IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42277 SUBJECT: IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 25/10/15 01:31:07 GMT FROM: Erik Blaufuss at University of Maryland, College Park <blaufuss(a)umd.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 25-10-14 at 18:33:11.58 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_BRONZE alert stream. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 2.226 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/141484_75492250.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 25-10-14 Time: 18:33:11.58 UT RA: 2.81 (+0.48/-0.49 deg 90% PSF containment) J2000 Dec: 2.91 (+0.49/-0.49 deg 90% PSF containment) J2000 We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event. 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 View this GCN Circular online at https://gcn.nasa.gov/circulars/42277. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40349] GRB 251013C: OHP/T193 further optical observations and possible color evolution
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42276 SUBJECT: GRB 251013C: OHP/T193 further optical observations and possible color evolution DATE: 25/10/15 00:11:23 GMT FROM: Christophe Adami at LAM <christophe.adami(a)lam.fr> C. Adami (LAM/Pytheas/AMU), B. Schneider (LAM), E. Le Floc'h (CEA/Irfu), N.A. Rakotondrainibe (LAM), V. Buat (LAM/Pytheas/AMU), S. Basa (Pytheas/OHP/LAM), M. Dennefeld (IAP) report on behalf of the MISTRAL GRB collaboration: We carried out further observations of the GRB 251013C optical and NIR afterglow (Palmerio et al., GCN 42223 ; Perez-Garcia et al., GCN 42225 ; Konno et al., GCN 42226 ; Martin-Carrillo et al., GCN 42227 ; Masi et al., GCN 42228 ; Palmerio et al., GCN 42229 ; Moskvitin et al., GCN 42230 ; Gompertz et al., GCN 42231 ; Lipunov et al., GCN 42235 ; Garnavich, GCN42240; Watson et al., GCN 42241 ; Lopez-Camara et al., GCN 42242 ; Zhang et al., GCN 42248; Brosio et al., GCN 42251; Reguitti et al., GCN 42253 ; Quintana-Ansaldo et al., GCN 42254; Maksut et al., GCN 42256; Ghosh et al., GCN 42261 ; Quadri et al., GCN 42262 ; Adami et al. GCN 42266 ; Peretto et al., GCN 42267 ; Ruocco et al., GCN 42269 ; Calapai, GCN 42275) using the T193cm telescope at Observatoire de Haute-Provence (France) equipped with the MISTRAL spectro-imager. We obtained 3 exposures of 10min followed by 1 exposure of 5min in the r-band, corresponding to T-T0 = 27.89 hr (mid-time). In addition, we obtained 2 exposures of 10min followed by 1 exposure of 15min in the g-band, corresponding to T-T0 = 28.71 hr (mid-time). The afterglow is well detected in the two bands and we measured the following preliminary magnitudes: g’ = 21.11 +/- 0.10 mag (AB) r’ = 21.29 +/- 0.07 mag (AB) This may suggest a color evolution compared to e.g. previous g-r values reported by Palmerio et al. (GCN 42229): 0.31 +/- 0.01 at T-T0 ~ 2.05 hr. In comparison, our preliminary values seem to indicate g’-r’ = -0.18 +/- 0.12 at T-T0 ~ 28.3 hr. The photometric calibration was performed using nearby stars from the PanSTARRS catalog and the magnitudes are not corrected for Galactic extinction. We used the STDWeb/STDPipe tools (Karpov 2025). We acknowledge the excellent support from the Observatoire de Haute-Provence and in particular Jean Balcaen and the SOPHIE observers J.B. Salomon and J.L. Halbwachs View this GCN Circular online at https://gcn.nasa.gov/circulars/42276. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40348] GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42275 SUBJECT: GRB 251013C: Calapai Observatory, Massa S. Giorgio (Messina), optical observation DATE: 25/10/14 23:48:43 GMT FROM: Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, Messina, Italy <giovannicalapai(a)tiscali.it> Giovanni Calapai at Calapai Astronomical Observatory, Massa S. Giorgio, (Messina) Italy Member of: GRB/UAI Gamma Ray Burst Section of Unione Astrofili Italiani. Report: We observed the field of GRB 251013C detected by SVOM (Rakotondrainibe et al., GCN 42222) with the 11 inches Schmidt-Cassegrain (Celestron 11) telescope F/D=6,3. The observations were started at 2025-10-13 19:01:08 UT (approximately 1.36 hours after burst) stacking 40 sets of unfiltered CCD image. The observations were carried out with clear skies and good visibility conditions. The OT was detected at the following position: RA (J2000.0) 23h 03m 20.56s Decl. (J2000.0) -00° 12' 37.00" We report our photometry analysis: HJD Exposure CR Mag Err ------------------------------------------- 2460962.295312 8x60s 15.56 0.01 2460962.301088 8x60s 15.75 0.01 2460962.306863 8x60s 15.97 0.01 2460962.312627 8x60s 16.09 0.01 2460962.318414 8x60s 16.16 0.01 2460962.324190 8x60s 16.20 0.01 2460962.329954 8x60s 16.27 0.01 2460962.335718 8x60s 16.41 0.01 2460962.341481 8x60s 16.53 0.01 2460962.347245 8x60s 16.61 0.01 2460962.353009 8x60s 16.68 0.01 2460962.358773 8x60s 16.69 0.01 2460962.364537 8x60s 16.72 0.01 2460962.370301 8x60s 16.80 0.01 2460962.376065 8x60s 16.80 0.01 2460962.381840 8x60s 16.90 0.01 2460962.387627 8x60s 16.91 0.01 2460962.393403 8x60s 17.02 0.01 2460962.399178 8x60s 17.02 0.01 2460962.404954 8x60s 17.17 0.01 2460962.410729 8x60s 17.17 0.02 2460962.416505 8x60s 17.22 0.02 2460962.422280 8x60s 17.23 0.02 2460962.428067 8x60s 17.31 0.02 2460962.433843 8x60s 17.35 0.02 2460962.439618 8x60s 17.38 0.02 2460962.445382 8x60s 17.44 0.02 2460962.451157 8x60s 17.43 0.02 2460962.456933 8x60s 17.58 0.03 2460962.462697 8x60s 17.56 0.03 2460962.468461 8x60s 17.70 0.03 2460962.474224 8x60s 17.62 0.03 2460962.479618 8x60s 17.72 0.03 2460962.485903 8x60s 17.75 0.03 2460962.491678 8x60s 17.86 0.04 2460962.497454 8x60s 18.02 0.05 2460962.503241 8x60s 18.03 0.05 2460962.509016 8x60s 17.97 0.05 2460962.514792 8x60s 17.99 0.05 2460962.521667 11x60s 18.06 0.05 Magnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied. Our observations are consistent with other already reported Perez-Garcia et al. (GCN circ. 42225), Konno et al. (GCN circ. 42226), Martin-Carrillo et al. (GCN circ. 42227), Masi (GCN circ. 42228), Palmerio et al. (GCN circ. 42229), Moskvitin et al. (GCN circ. 42230), Gompertz et al. (GCN circ. 42231), Watson et al. (GCN circ. 42241), López-Cámara et al. (GCN circ. 42242), Zhang et al. (GCN circ. 42248), Brosio et al. (GCN circ. 42251), Quintana-Ansaldo et al. (GCN circ. 42254), Maksut et al. (GCN circ. 42256), Quadri et al.(GCN 42262), Adami et al.(GCN 42266), Peretto et al.(GCN 42267), Ruocco et al. (GCN 42269). The message may be cited. View this GCN Circular online at https://gcn.nasa.gov/circulars/42275. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40347] GRB 251014D: Swift detection of a burst
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42274 SUBJECT: GRB 251014D: Swift detection of a burst DATE: 25/10/14 22:50:35 GMT FROM: Simone Dichiara at Pennsylvania State University <sbd5667(a)psu.edu> N. J. Klingler (GSFC/UMBC/CRESSTII), S. Dichiara (PSU), R. Gupta (NASA GSFC), N. P. M. Kuin (UCL-MSSL), A. Mei (INAF-OAB), C. Salvaggio (INAF-OAB) and T. Sbarrato (INAF-OAB) report on behalf of the Neil Gehrels Swift Observatory Team: At 21:54:40.55 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 251014D (trigger=1404126). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 323.918, -41.839 which is RA(J2000) = 21h 35m 40s Dec(J2000) = -41d 50' 20" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve is not available because of a telemetry gap; however, the rate significance of 8.71 indicates that the event is likely real. The XRT began observing the field at 21:57:16.2 UT, 155.7 seconds after the BAT trigger. No source was detected in the 2.5-s promptly available image. We are waiting for the full dataset to detect and localise the XRT counterpart. The UVOT source list for the first white image shows no detection of a new source. Typical upper limits are 17th magnitude. Further details will become available when the full data are downloaded. Burst Advocate for this burst is N. J. Klingler (noelklin AT umbc.edu) Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/) View this GCN Circular online at https://gcn.nasa.gov/circulars/42274. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40346] GRB 251014A: PRIME near-infrared upper limits
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42273 SUBJECT: GRB 251014A: PRIME near-infrared upper limits DATE: 25/10/14 22:47:00 GMT FROM: Joe Durbak at UMD <gcn.joedurbak(a)gmail.com> J. Durbak (UMD), O. Guiffreda (UMD), N. Passaleva (U Rome), M. Elkabir (U Rome), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), S. B. Cenko (NASA/GSFC) Following the Swift BAT (Ambrosi et al, GCN 42238) and Fermi GBM (Fermi GBM Team, GCN 42237) detection, we observed the transient field in J-filter with PRIME ~1 hour after Swift and Fermi detection. After comparing a previous J-band epoch observed in this location on 2024-11-17, we detect no new sources in J-band within the Swift BAT localization region. Using nearby 2MASS stars for preliminary calibration we derive a limiting magnitude >19.7 AB for the previous epoch, not corrected for Galactic extinction. Further observations are planned to obtain deeper imaging. 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/42273. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40345] GRB 251014A: PRIME near-infrared upper limits
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42273 SUBJECT: GRB 251014A: PRIME near-infrared upper limits DATE: 25/10/14 22:47:00 GMT FROM: Joe Durbak at UMD <gcn.joedurbak(a)gmail.com> J. Durbak (UMD), O. Guiffreda (UMD), N. Passaleva (U Rome), M. Elkabir (U Rome), A. S. Kutyrev (NASA/GSFC), E. Troja (U Rome), S. B. Cenko (NASA/GSFC) Following the Swift BAT (Ambrosi et al, GCN 42238) and Fermi GBM (Fermi GBM Team, GCN 42237) detection, we observed the transient field in J-filter with PRIME ~1 hour after Swift and Fermi detection. After comparing a previous J-band epoch observed in this location on 2024-11-17, we detect no new sources in J-band within the Swift BAT localization region. Using nearby 2MASS stars for preliminary calibration we derive a limiting magnitude >19.7 AB for the previous epoch, not corrected for Galactic extinction. Further observations are planned to obtain deeper imaging. 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/42273. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40344] GRB 251014A: VLT/FORS2 Optical Observation
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42270 SUBJECT: GRB 251014A: VLT/FORS2 Optical Observation DATE: 25/10/14 21:28:42 GMT FROM: Roberto Ricci at INAF-IRA <ricci(a)ira.inaf.it> Muskan Yadav (U Rome), Roberto Ricci (U Rome), Yu-Han Yang (U Rome), Rosa L. Becerra (U Rome) and Eleonora Troja (U Rome) report on behalf of the ERC BHianca team: We observed the field of GRB 251014A detected by Fermi (Fermi Team et al., GCN 42237) and Swift/BAT (Ambrosi et al., GCN 42238) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began 7.55 hours after the trigger and were carried out in the R filter with an average airmass of ~1.5. Having no reference image deep enough to compare with our science image, at this stage we are not able to determine whether there are new sources down to the limiting magnitude probed by FORS2. Further observations or an arcsec X-ray counterpart are required to make such a claim. We thank the staff at the VLT for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42270. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40343] GRB 251014C: Fermi GBM Final Localization
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42272 SUBJECT: GRB 251014C: Fermi GBM Final Localization DATE: 25/10/14 21:48:07 GMT FROM: Suman Bala at USRA <sumanbala2210(a)gmail.com> The Fermi GBM team reports the detection of a likely LONG GRB "At 20:45:58.96 UT on 14 October 2025, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 251014C (trigger 782167563/251014865). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 133.36, Dec = 14.24 (J2000 degrees, equivalent to J2000 8h 53m, +14d 14'), with a statistical uncertainty of 5.09 degrees. The angle from the Fermi LAT boresight is 84 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251014865/… The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251014865/… The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2025/bn251014865/…" View this GCN Circular online at https://gcn.nasa.gov/circulars/42272. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40342] GRB 251014A: Glowbug gamma-ray detection of a likely short burst
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42271 SUBJECT: GRB 251014A: Glowbug gamma-ray detection of a likely short burst DATE: 25/10/14 21:37:02 GMT FROM: C.C. Cheung at Naval Research Lab <Teddy.Cheung(a)nrl.navy.mil> R. Woolf, C.C. Cheung, 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 251014A, which was also detected by Fermi/GBM (GCN 42237, 42249) and Swift/BAT (GCN 42238). Using an adaptive window with a resolution of 32-ms, the burst onset is determined to be 2025-10-14 00:28:30.032 with a duration of 1.02 s and a total significance of about 9.9 sigma. The light curve is dominated by a single peak. 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/42271. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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[vsnet-grb-info 40341] GRB 250821A: VLT/FORS2 Optical Observation
by GCN Circulars 14 Oct '25

14 Oct '25

TITLE: GCN CIRCULAR NUMBER: 42270 SUBJECT: GRB 250821A: VLT/FORS2 Optical Observation DATE: 25/10/14 21:28:42 GMT FROM: Roberto Ricci at INAF-IRA <ricci(a)ira.inaf.it> Muskan Yadav (U Rome), Roberto Ricci (U Rome), Yu-Han Yang (U Rome), Rosa L. Becerra (U Rome) and Eleonora Troja (U Rome) report on behalf of the ERC BHianca team: We observed the field of GRB 251014A detected by Fermi (Fermi Team et al., GCN 42237) and Swift/BAT (Ambrosi et al., GCN 42238) with the FORS2 imager on the ESO VLT UT1 (Antu). Observations began 7.55 hours after the trigger and were carried out in the R filter with an average airmass of ~1.5. Having no reference image deep enough to compare with our science image, at this stage we are not able to determine whether there are new sources down to the limiting magnitude probed by FORS2. Further observations or an arcsec X-ray counterpart are required to make such a claim. We thank the staff at the VLT for the rapid execution of these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/42270. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

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