//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30957 SUBJECT: IceCube-211023A - IceCube observation of a high-energy neutrino candidate track-like event DATE: 21/10/23 09:47:02 GMT FROM: Dr. Massimiliano Lincetto at Ruhr-Universitaet Bochum The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2021/10/23 at 08:31:18.31 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 3.2 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/135832_55176071.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2021/10/23 Time: 08:31:18.31 UT RA: +253.30 (+1.05 / -1.08 deg 90% PSF containment) J2000 Dec: -1.72 (+1.16 / -1.11 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. One gamma-ray source, 4FGL J1653.6-0158, is located within the 90% of the error region, 0.27 deg away from the best-fit position. The source is associated with the pulsar PSR J1653-0158. 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: 30959 SUBJECT: IceCube Alert 211023.36: Global MASTER-Net observations report DATE: 21/10/23 17:52:18 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V. Lipunov, E. Gorbovskoy, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, F.Balakin, V.Vladimirov, D. Vlasenko, I.Gorbunov, D.Zimnukhov, V.Senik, T.Pogrosheva, D.Kuvshinov, D. Cheryasov (Lomonosov Moscow State University, SAI, Physics Department), R. Podesta, C.Lopez, F. Podesta, C.Francile (Observatorio Astronomico Felix Aguilar OAFA), R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias), D. Buckley (South African Astronomical Observatory), O.A. Gres, N.M. Budnev, O.Ershova (Irkutsk State University, API), A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo Observatory), V. Yurkov, A. Gabovich, Yu. Sergienko (Blagoveschensk Educational State University) 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 211023.36 (trigger No 55176071,16h 54m 20.18s , -01d 50m 11.0s, R=0.584) errorbox 33119 sec after notice time and 33168 sec after trigger time at 2021-10-23 17:44:07 UT, with upper limit up to 15.1 mag. Observations started at twilight. The observations began at zenith distance = 68 deg. The sun altitude is -10.5 deg. The galactic latitude b = 24 deg., longitude l = 17 deg. Real time updated cover map and OT discovered available here: https://master.sai.msu.ru/site/master2/observ.php?id=1762298 We obtain a following upper limits. Tmid-T0 | Date Time | Site | Coord (J2000) |Filt.| Expt. | Limit| Comment _________|_____________________|_____________________|____________________________________|_____|_______|_______|________ 33199 | 2021-10-23 17:44:07 | MASTER-SAAO | (16h 54m 34.56s , -00d 38m 15.7s) | C | 60 | 13.8 | 33279 | 2021-10-23 17:45:26 | MASTER-SAAO | (17h 02m 36.87s , -00d 38m 33.1s) | C | 60 | 15.1 | 33358 | 2021-10-23 17:46:46 | MASTER-SAAO | (16h 55m 32.02s , -02d 31m 53.9s) | C | 60 | 14.4 | Filter C is a clear (unfiltred) band. The observation and reduction will continue. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30971 SUBJECT: IceCube-211023A: No neutrino counterpart detected with ANTARES DATE: 21/10/24 12:37:26 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 bronze track event IceCube-211023A (GCN #30957 ). The reconstructed origin was slightly above the horizon for ANTARES at the time of the alert (+0.8 degrees). No horizontal 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 half of the time. This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of about 12 GeV.cm^-2 over the energy range 3 TeV – 3 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 48 GeV.cm^-2 (600 GeV - 300 TeV) for an E^-2.5 spectrum. A search over an extended time window of +/- 1 day has also yielded no detection (51% 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: 30978 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-211023A DATE: 21/10/24 20:50:39 GMT FROM: Simone Garrappa at DESY S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) and R. de Menezes (Univ. of Wuerzburg, Univ. of Sao Paulo) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the high-energy IC211023A neutrino event (GCN 30957) 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 2021-10-23 at 08:31:18.31 UT (T0) with J2000 position RA = 253.30 (+1.05,-1.08) deg, Decl. = -1.72 (+1.16, -1.11) deg (90% PSF containment). One cataloged gamma-ray (>100 MeV) source is located within the 90% IC211023A localization region. This is 4FGL J1653.6-0158 (4FGL-DR2, The Fermi-LAT collaboration 2020, ApJS, 247, 33), identified as PSR J1653-0158 (Nieder et al. 2020 ApJL 202, 46). Based on a preliminary analysis of the LAT data over the timescales of 1-day and 1-month prior to T0, this object is not significantly detected (> 5 sigma). 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 IC211023A best-fit position. Assuming a power-law spectrum (photon index = 2.0 fixed) for a point source at the IC211023A best-fit position, the >100 MeV flux upper limit (95% confidence) is < 8.8e-10 ph cm^-2 s^-1 for ~13-years (2008-08-04 to 2021-10-23 UTC), and < 1.6e-8 (< 1.9e-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 S. Garrappa (simone.garrappa at desy.de) and S. Buson (sara.buson 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 30999 SUBJECT: IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube DATE: 21/10/25 20:00:34 GMT FROM: Alex Pizzuto at ICECUBE/U of Wisconsin 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-211023A (https://gcn.gsfc.nasa.gov/gcn3/30957.gcn3) in a time range of 1000 seconds centered on the alert event time (2021-10-23 08:22:58.310 UTC to 2021-10-23 08:39:38.310 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-211023A. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-211023A is 1.5e-01 GeV cm^-2 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 range between 3e+02 GeV and 2e+05 GeV. A subsequent search was performed including 2 days of data centered on the alert event time (2021-10-22 08:31:18.310 UTC to 2021-10-24 08:31:18.310 UTC). In this case, we report a p-value of 0.09, consistent with no significant excess of track events. The IceCube sensitivity to neutrino point sources with an E^-2.5 spectrum (E^2 dN/dE at 1 TeV) within the locations spanned by the 90% spatial containment region of IceCube-211023A is 1.6e-01 GeV cm^-2 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@icecube.wisc.edu. [1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 31117 SUBJECT: IceCube-211023A: not observable by Fermi-GBM DATE: 21/11/24 20:38:04 GMT FROM: Cori Fletcher at USRA C. Fletcher (USRA) reports on behalf of the Fermi-GBM team: For the IceCube high-energy neutrino candidate event IceCube-211023A (GCN 30957), the reported position: RA: +253.30 (+1.05 / -1.08 deg 90% PSF containment) J2000 Dec: -1.72 (+1.16 / -1.11 deg 90% PSF containment) J2000 was occulted by the Earth for Fermi-GBM from approximately from 0.1 minutes prior until 34.4 minutes after event time. Therefore, the GBM observations are not constraining for prompt gamma-ray emission.