//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31093 SUBJECT: IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event DATE: 21/11/17 18:27:03 GMT FROM: Marcos Santander at U. Alabama/IceCube The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2021/11/17 at 03:50:57.184 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_GOLD alert stream. The average astrophysical neutrino purity for Gold alerts is 50%. This alert has an estimated false alarm rate of 1.166 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/135908_43512334.amon), more sophisticated reconstruction algorithms were attempted offline. However, the event topology of this event prevented this reconstruction from converging. Therefore, at this time we retain the online event direction as our best estimate of the event direction: Date: 2021/11/17 Time: 03:50:57.184 UT RA: 225.93 (+/- 0.51 deg 90% PSF containment) J2000 Dec: -0.20 (+/- 0.51 deg 90% PSF containment) J2000 We note that the online error estimates are unchanged from the initial online alert estimates, and are potentially underestimated compared to those from the offline reconstructions. We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. There are no Fermi 4FGL or 3FHL catalog sources in the 90% uncertainty region. The nearest gamma-ray source in either catalog is 4FGL J1512.2+0202 at RA: 228.07 deg, Dec: 2.04 deg (3.10 deg away from the best-fit event position). 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@icecube.wisc.edu //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31094 SUBJECT: Search for counterpart to IceCube-211117A with ANTARES DATE: 21/11/18 08:15:33 GMT FROM: Antoine Kouchner at ANTARES Collaboration Alexis Coleiro (APC/Universite de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration. Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported gold track event IceCube-211117A (GCN#31093 ). The reconstructed origin was 11.5 degrees below the horizon for ANTARES at the time of the alert. No muon neutrino candidate events were recorded within 90% error box of the IceCube event during a +/- 1h time-window centered on the IceCube event time, and over which the potential source remained visible. This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of about 15 GeV.cm^-2 over the energy range 3 TeV – 3.5 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 43 GeV.cm^-2 (610 GeV - 320 TeV) for an E^-2.5 spectrum. A search over an extended time window of +/- 1 day has also yielded no detection (50% visibility). ANTARES is the largest undersea neutrino detector (Mediterranean Sea) and it is primarily sensitive to astrophysical neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31097 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-211117A DATE: 21/11/20 10:52:28 GMT FROM: Sara Buson at GSFC/Fermi R. de Menezes (Univ. of Wuerzburg, Univ. of Sao Paulo), S. Garrappa (DESY-Zeuthen) and S. Buson (Univ. of Wuerzburg) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC211117A neutrino event (GCN 31093) 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 2021-11-17 at 18:27:03 UT (T0) with J2000 position RA = 225.93 (+0.51,-0.51) deg, Decl. = -0.20 (+0.51, -0.51) deg (90% PSF containment). No cataloged gamma-ray (>100 MeV) source is located within the 90% IC211117A localization region (4FGL-DR2, The Fermi-LAT collaboration 2020, ApJS, 247, 33). We searched for intermediate (days to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (> 5 sigma) new excess emission (> 100 MeV) at the IC211117A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC211117A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 9.5e-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 to 2021-11-17 UTC), and < 4.5e-9 (< 1.26e-7) 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 these observations the Fermi-LAT contact persons are R. de Menzes (raniere.menezes at uni-wuerzburg.de) and S. Garrappa (simone.garrappa at desy.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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31119 SUBJECT: IceCube-211117A: not observable by Fermi-GBM DATE: 21/11/24 20:41:10 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) reports on behalf of the Fermi-GBM team: At the time of the neutrino candidate IceCube-211117A (GCN 31093), Fermi was passing through the South Atlantic Anomaly from 25.8 minutes prior until 2.0 minutes after the trigger time; therefore the GBM detectors were disabled.