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

[vsnet-grb-info 39100] EP/WXT 01709181970: GOTO observations confirm stellar variability
by GCN Circulars 09 Jul '25

09 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41048 SUBJECT: EP/WXT 01709181970: GOTO observations confirm stellar variability DATE: 25/07/09 08:35:58 GMT FROM: Amit Kumar at Royal Holloway - UoL/ U of Warwick, UK <amitkundu515(a)gmail.com> A. Kumar, D. O'Neill, G. Ramsay, B. P. Gompertz, R. Starling, K. Ackley, M. J. Dyer, J. Lyman, K. Ulaczyk, B. Godson, D. Steeghs, D. K. Galloway, V. Dhillon, P. O'Brien, K. Noysena, R. Kotak, R. P. Breton, L. K. Nuttall, and J. Casares report on behalf of the GOTO collaboration: We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022, Dyer et al. 2024) in response to EP/WXT trigger ID 01709181970 (Peng et al. GCN 41045). Targeted observations were obtained using the GOTO North on 2025-07-08 22:31:40 UT (8.301 minutes post-trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm). Images were processed immediately after acquisition using the GOTO pipeline. Difference imaging was performed using deeper template observations of the same pointings. Source candidates were initially filtered using a classifier (Killestein et al. 2021) and cross-matched against a variety of contextual and minor planet catalogues. Human vetting was carried out in real time on any candidates that passed the above checks. No new transients within the EP/WXT localisation are found, except for a variable star Gaia DR3 4587345820285675136, which is also reported by Perez-Garcia et al. GCN 41047. This source exhibited significant variability in GOTO archival L-band images, brightening from magnitude 20.2 to 18.8 (AB) between 2025-04-07 and 2025-06-15. In our post-trigger observation on 2025-07-08 at 22:31:40 UT (8.30 minutes post-trigger), the source appeared much brighter and was saturated even in our single frames, indicating it was brighter than ~12 mag. Magnitudes were calibrated using ATLAS-REFCAT2 (Tonry et al. 2018) and are not corrected for Galactic extinction. GOTO (https://goto-observatory.org) is a network of telescopes that is principally funded by the STFC and operated at the Roque de los Muchachos Observatory on La Palma, Spain, and Siding Spring Observatory in NSW, Australia, on behalf of a consortium including the University of Warwick, Monash University, Armagh Observatory & Planetarium, the University of Leicester, the University of Sheffield, the National Astronomical Research Institute of Thailand (NARIT), the University of Turku, the University of Portsmouth, the University of Manchester and the Instituto de Astrofisica de Canarias (IAC). View this GCN Circular online at https://gcn.nasa.gov/circulars/41048. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39099] EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6
by GCN Circulars 09 Jul '25

09 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41047 SUBJECT: EP-WXT trigger 01709181970. confirmation of a stellar flare by BOOTES-6 DATE: 25/07/09 05:14:17 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia <ajct(a)iaa.es> I. Perez-Garcia, S.-Y. Wu, E. Fernandez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, G. Garcia-Segura and A. J. Castro-Tirado (IAA-CSIC, Granada), P. J. Meintjes and H. J. van Heerden (UFS, South Africa), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), M. Gritsevich (Univ. of Helsinki) and C. J. Perez del Pulgar (UMA, Malaga), on behalf of a larger collaboration, report: Following the detection of trigger 01709181970 by EP-WXT (Peng et al. GCNC 41045), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) responded to the alert on July 08, 22:29 UT (i.e. 6 min after detection and 2 min after notification). Within the reported EP-FXT error circle we find the star Gaia DR3 4587345820285675136 decreasing in brightness from 11.3 to 12.2 mag in clear filter and using Gaia DR3 Gmag magnitude as reference, during a ~1 hour time interval, confirming as due to a stellar flare. We thank the staff at Boyden Observatory for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/41047. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39098] EP250704a/GRB 250704B: 10 GHz VLA detection
by GCN Circulars 09 Jul '25

09 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41046 SUBJECT: EP250704a/GRB 250704B: 10 GHz VLA detection DATE: 25/07/09 04:57:07 GMT FROM: Roberto Ricci at INAF-IRA <ricci(a)ira.inaf.it> Roberto Ricci, Rosa L. Becerra, Eleonora Troja (Rome U.) report on behalf of the ERC BHianca team: We observed the field of GRB 250704B/EP250704a (Wang et al. GCN 40940; Li et al. GCN 40491) with the Jansky Very Large Array (VLA) at the center frequency of 10 GHz (with a bandwidth of 4 GHz) in C-array configuration on 2025 July 8th at mid observing time 07:53 UT (3.98 days after burst). A radio source was detected within the error circle of optical transient position (Schneider et al. GCN 40942) with a flux density of 92 +/- 7 microJy. This is consistent with the radio detection reported by Schroeder et al. GCN 41038. Further observations are planned. We thank the VLA staff for executing the observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/41046. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39097] The EP-WXT trigger 01709181970 is likely a flaring star
by GCN Circulars 09 Jul '25

09 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41045 SUBJECT: The EP-WXT trigger 01709181970 is likely a flaring star DATE: 25/07/09 03:30:49 GMT FROM: EP Team at NAOC/CAS <ep_ta(a)bao.ac.cn> H.L. Peng (NNU), C. Zhou, P. Y. Han (HUST) , Q. C. Liu (THU), B. B. Zhang (NAO, CAS), G. Y. Zhao (SYSU), Z. X. Ling (NAO, CAS) on behalf of the Einstein Probe (EP) team: The EP-WXT trigger 01709181970 at the time of 2025-07-08T22:23:23, is likely a stellar flare associated with Gaia DR3 4587345820285675136. The estimated flux of the flare is around 2.4 x 10^-10 erg/s/cm^2 in 0.5-4.0 keV, corresponding to an X-ray luminosity of around 4.5 x 10^31 erg/s. Launched on January 9, 2024, EP is a space X-ray observatory to monitor the soft X-ray sky with X-ray follow-up capability (Yuan et al. 2022, Handbook of X-ray and Gamma-ray Astrophysics). View this GCN Circular online at https://gcn.nasa.gov/circulars/41045. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39096] GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow
by GCN Circulars 09 Jul '25

09 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41044 SUBJECT: GRB250702 B,D,E / EP250702a: MOSFIRE imaging of the afterglow DATE: 25/07/09 03:22:13 GMT FROM: Tomas Ahumada Mena at Caltech <tahumada(a)caltech.edu> Kaustav K. Das, Kritti Sharma, Viraj Karambelkar, Mansi Kasliwal, Tomas Ahumada (Caltech), Xander J. Hall (CMU) on behalf of the ZTF collaboration: We used MOSFIRE on Keck I to image the afterglow candidate reported by Martin-Carrillo et al. (GCN 40924), likely associated with EP250702a (Cheng et al., GCNs 40906, 40917) and GRB 250702B, D, and E, detected by Fermi/GBM (Fermi GBM Team, GCNs 40883, 40886, 40890), Swift/BAT (via GUANO; DeLaunay et al., GCN 40903), and Konus/Wind (Frederiks et al., GCN 40914). Observations began at 2025-07-05T10:14:00 UTC and consisted of imaging in the J, H, and Ks bands. We detect the afterglow candidate in the Ks band with m_K = 21.7±0.1 (AB). The source is not detected in the H and J bands, with limiting magnitudes of m_H > 22.4 (AB) and m_J > 22.8 (AB), respectively. These results are consistent with a temporal decay index of ~1.7 (Martin-Carrillo et al., GCN 40924; Levan et al., GCN 40961). We thank the Keck Observatory staff for their support in facilitating these observations. View this GCN Circular online at https://gcn.nasa.gov/circulars/41044. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39095] LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume
by GCN Circulars 08 Jul '25

08 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41043 SUBJECT: LIGO/Virgo/KAGRA S250704ab: NED Galaxies in the 4-Update Localization Volume DATE: 25/07/08 23:42:55 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 S250704ab-4-Update sky localization with the NED Local Volume Sample (NED-LVS; Cook et al. 2023), which is a subset of NED with a redshift or redshift-independent distance less than 1000 Mpc. We find 611 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/S250704ab/4 Top 20 List Download: https://ned.ipac.caltech.edu/uri/NED::GWFglist/fits/S250704ab/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| |-------------------------|--------------|--------------|-------|-----------|-----------|-------|---------|------------|------------|------------|------------|--------|----------| |WISEA J053516.57+442623.7| 83.81906| 44.43992| G| 509.25| null| null| null| 13.033| 0.125| 10.237| 0.006|1.71e-06| 1.82e-08| |WISEA J054250.35+455634.2| 85.70983| 45.94286| G| 483.57| null| null| null| 12.898| 0.119| 10.988| 0.007|3.12e-06| 1.51e-08| |WISEA J053923.04+451743.3| 84.84603| 45.29538| G| 605.62| null| null| null| 12.453| 0.119| 11.620| 0.009|3.61e-06| 1.51e-08| |WISEA J053539.37+465222.0| 83.91405| 46.87278| G| 461.85| null| null| null| 13.055| 0.145| 11.308| 0.009|4.47e-06| 1.46e-08| |WISEA J054541.19+423211.5| 86.42163| 42.53653| G| 510.30| null| null| null| 13.697| 0.200| 10.637| 0.006|1.80e-06| 1.33e-08| |WISEA J054353.77+433318.3| 85.97407| 43.55511| G| 578.18| null| null| null| 13.998| 0.142| 11.554| 0.010|2.53e-06| 1.03e-08| |WISEA J053847.35+462114.1| 84.69732| 46.35394| G| 470.87| null| null| null| 12.551| 0.100| 12.067| 0.011|5.61e-06| 9.44e-09| |WISEA J053634.97+455156.1| 84.14573| 45.86561| G| 530.56| null| null| null| 13.218| 0.133| 12.261| 0.014|4.81e-06| 8.65e-09| |WISEA J053258.59+491405.3| 83.24413| 49.23481| G| 523.55| null| null| null| 13.311| 0.109| 9.424| 0.006|3.47e-07| 8.31e-09| |WISEA J053723.16+460044.4| 84.34651| 46.01236| G| 407.49| null| null| null| 13.495| 0.191| 11.529| 0.007|3.82e-06| 7.98e-09| |WISEA J054001.86+462259.3| 85.00789| 46.38354| G| 428.04| null| null| null| 12.805| 0.107| 11.667| 0.008|3.94e-06| 7.89e-09| |WISEA J054201.60+460028.5| 85.50669| 46.00793| G| 563.41| null| null| null| 12.939| 0.138| 11.887| 0.008|2.69e-06| 7.68e-09| |WISEA J053208.93+475055.0| 83.03725| 47.84862| G| 557.44| null| null| null| 13.767| 0.225| 11.121| 0.007|1.33e-06| 7.56e-09| |WISEA J053425.20+462348.5| 83.60502| 46.39682| G| 552.92| null| null| null| 13.309| 0.150| 12.061| 0.011|2.86e-06| 6.71e-09| |WISEA J054301.87+435708.0| 85.75780| 43.95222| G| 559.29| null| null| null| 13.811| 0.207| 12.385| 0.016|3.59e-06| 6.34e-09| |WISEA J053625.76+453611.0| 84.10735| 45.60307| G| 500.51| null| null| null| 13.030| 0.166| 12.439| 0.024|4.61e-06| 6.27e-09| |WISEA J054328.21+450858.0| 85.86756| 45.14945| G| 449.66| null| null| null| 13.406| 0.172| 11.996| 0.011|3.70e-06| 6.12e-09| |WISEA J053715.47+424503.7| 84.31447| 42.75103| G| 404.22| null| null| null| 12.767| 0.107| 9.881| 0.006|6.42e-07| 6.01e-09| |WISEA J053606.08+462143.1| 84.02537| 46.36199| G| 573.70| null| null| null| 13.989| 0.253| 12.477| 0.020|3.44e-06| 5.93e-09| |WISEA J054047.69+451204.5| 85.19873| 45.20127| G| 455.94| null| null| null| 13.402| 0.074| 12.608| 0.024|6.10e-06| 5.84e-09| Table 1: Top 20 galaxies in NED-LVS that fall in the 90% probability volume for S250704ab 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/41043. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39094] IceCube-250706A: No Candidates from WINTER
by GCN Circulars 08 Jul '25

08 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41042 SUBJECT: IceCube-250706A: No Candidates from WINTER DATE: 25/07/08 20:35:14 GMT FROM: Robert David Stein at JSI <rdstein(a)umd.edu> Robert Stein (UMD), Danielle Frostig (CfA), Viraj Karambelkar (Caltech), Mansi Kasliwal (Caltech), Nathan Lourie (MIT), Geoffrey Mo (MIT), and Robert Simcoe (MIT) report: On behalf of Wide-Field Infra-Red Transient Explorer (WINTER) collaboration: We observed the localization region of the neutrino event IceCube-250706A (Zegarelli et. al, GCN 40994) with the 1.2 sq. degree near-IR WINTER camera on the Palomar 1-m telescope (Lourie et al. 2021, Frostig et al. 2024). We conducted observations in J-band beginning at 2025-07-07 02:42 UTC, approximately 13.5 hours after event time. Our observations covered a total of 0.7 sq. deg. of sky for which reference images were available, corresponding to 77.3% of the total probability. Our observations reached a median depth of 18.8 AB mag. The images were processed using the WINTER data reduction pipeline implemented with mirar (https://github.com/winter-telescope/mirar, https://doi.org/10.5281/zenodo.13352565) We use data from the UKIRT Hemisphere survey (Dye et al. 2018) as references for image subtraction. We search for WINTER sources with multiple detections, and for WINTER sources with cross-matches in the alert stream of the Zwicky Transient Facility (Bellm et al. 2019). After removing likely stellar sources and likely subtraction artefacts, we find no candidate counterparts. This is consistent with similar non-detections reported in the optical by Globus et al. (GCN 41003), Becerra et al. (GCN 41004) and Stein et al. (GCN 41040). Observations of this field will continue as part of the WINTER neutrino follow-up program. WINTER (Wide-field INfrared Transient ExploreR) is a partnership between MIT and Caltech, housed at Palomar Observatory, and funded by NSF MRI, NSF AAG, the David and Lucile Packard Foundation, and the MIT Kavli Institute for Astrophysics and Space Research. View this GCN Circular online at https://gcn.nasa.gov/circulars/41042. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39093] IPN triangulation of GRB 250706C (consistent with the GRB 250706B)
by GCN Circulars 08 Jul '25

08 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41041 SUBJECT: IPN triangulation of GRB 250706C (consistent with the GRB 250706B) DATE: 25/07/08 19:30:06 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia(a)mail.ioffe.ru> A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin on behalf of the HEND/Mars Odyssey team, A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, E. Burns on behalf of the IPN, and W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr, and A.S. Gardner on on behalf of the GRS-Odyssey GRB team, report: The very bright, long-duration GRB 250706C (Konus-Wind detection: Frederiks et al., GCNs 41013, 41027; Fermi-LAT detection: Longo et al., GCN 41019) was detected by Konus-Wind and Mars-Odyssey (HEND) at about 60322 s UT (16:45:22), ~1200 s before GRB 250706B (SVOM detection: Palmerio et al, GCNs 40989, 41026) We have triangulated it to a Konus-HEND annulus centered at RA(2000)=342.841 deg (22h 51m 22s) Dec(2000)=-8.288 deg (-8d 17' 19"), whose radius is 63.671 +/- 0.024 deg (3 sigma). This localization may be improved. The SVOM/ECLAIRs source localization reported for GRB 250706B (GCN 40989) is consistent with the Konus-HEND annulus, the Konus-Wind ecliptic latitude response and the Fermi-LAT position (GCN 41019), indicating that GRB 250706B and GRB 250706C are distinct emission episodes of the same GRB. A triangulation map and HEALPix FITS file are posted at http://www.ioffe.ru/LEA/GRBs/GRB250706_T60322/IPN/ The HEALPix triangulation map is the multi-order HEALPix in units of probability density. View this GCN Circular online at https://gcn.nasa.gov/circulars/41041. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39092] IceCube-250706A: No Candidates from the Zwicky Transient Facility
by GCN Circulars 08 Jul '25

08 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41040 SUBJECT: IceCube-250706A: No Candidates from the Zwicky Transient Facility DATE: 25/07/08 19:04:15 GMT FROM: Robert David Stein at JSI <rdstein(a)umd.edu> Robert Stein (JSI), Jannis Necker (DESY), Anna Franckowiak (Ruhr University Bochum) and Akshay Eranhalodi (DESY) report: On behalf of the Zwicky Transient Facility (ZTF) and Global Relay of Observatories Watching Transients Happen (GROWTH) collaborations: As part of the ZTF neutrino follow up program (Stein et al. 2023), we observed the localization region of the neutrino event IceCube-250706A (Zegarelli et. al, GCN 40994) with the Palomar 48-inch telescope, equipped with the 47 square degree ZTF camera (Bellm et al. 2019, Graham et al. 2019). We started observations in the g- and r-band beginning at 2025-07-07 05:03 UTC, approximately 15.8 hours after event time. We covered 67.1% (0.6 sq deg) of the reported localization region. This estimate accounts for chip gaps. Each exposure was 300s with a typical depth of 21.0 mag. The images were processed in real-time through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts (Masci et al. 2019). AMPEL (Nordin et al. 2019, Stein et al. 2021) was used to search the alerts database for candidates. We reject stellar sources (Tachibana and Miller 2018) and moving objects, and apply machine learning algorithms (Mahabal et al. 2019). No candidate counterparts were detected. This is consistent with similar non-detections reported by Globus et al. (GCN 41003) and Becerra et al. (GCN 41004). Observations of this field will continue as part of our standard ToO cadence for high-energy neutrinos (Stein et al. 2023). Based on observations obtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project. ZTF is supported by the National Science Foundation under Award #2407588 and a partnership including Caltech, USA; Caltech/IPAC, USA; University of Maryland, USA; University of California, Berkeley, USA; University of Wisconsin at Milwaukee, USA; Cornell University, USA; Drexel University, USA; University of North Carolina at Chapel Hill, USA; Institute of Science and Technology, Austria; National Central University, Taiwan, and OKC, University of Stockholm, Sweden. Operations are conducted by Caltech's Optical Observatory (COO), Caltech/IPAC, and the University of Washington at Seattle, USA. GROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949. Alert distribution service provided by DIRAC@UW (Patterson et al. 2019). Alert database searches are done by AMPEL (Nordin et al. 2019). Alert filtering is performed with the nuztf (Stein et al. 2021, https://github.com/desy-multimessenger/nuztf ). View this GCN Circular online at https://gcn.nasa.gov/circulars/41040. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0

[vsnet-grb-info 39091] IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
by GCN Circulars 08 Jul '25

08 Jul '25

TITLE: GCN CIRCULAR NUMBER: 41039 SUBJECT: IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 25/07/08 18:56:33 GMT FROM: A. Zegarelli at Ruhr University Bochum <azegarelli(a)icecube.wisc.edu> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 25-07-08 at 14:05:19.54 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 1.6259 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/141112_11292662.amon) more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 25-07-08 Time: 14:05:19.54 UT RA: 222.71 (+0.52/-0.54 deg 90% PSF containment) J2000 Dec: 26.49 (+0.47/-0.47 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/41039. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0L…

1 0