//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23338 SUBJECT: IceCube-181014A - IceCube observation of a high-energy neutrino candidate event DATE: 18/10/14 14:54:49 GMT FROM: Ignacio Taboada at Georgia Inst of Tech The IceCube Collaboration (http://icecube.wisc.edu/) reports: On October 14, 2018, IceCube detected a track-like, very-high-energy event with a high probability of being of astrophysical origin. The event was identified by the High Energy Starting Event (HESE) track selection. The IceCube detector was in a normal operating state. HESE tracks have a neutrino interaction vertex inside the detector and produce a muon that only partially traverses the detector volume, and have a high light level (a proxy for energy). An inspection of the event does not reveal any feature to rule out this event as an astrophysical candidate. However, this event has a light level that is right above the analysis threshold so there is a non-negligible probability that this event is an atmospheric background. After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon/12296708_131624.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2018/10/14 Time: 11:52:46 UT RA: 225.15 [-2.85,+1.40] (deg 90% PSF containment) J2000 Dec: -34.80 [-1.85,+1.15] (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. 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: 23339 SUBJECT: Fermi-LAT Gamma-ray Observations of IceCube-181014A DATE: 18/10/15 00:42:07 GMT FROM: Sara Buson at GSFC/Fermi T. Venters (tonia.m.venters at nasa.gov), S. Garrappa (DESY-Zeuthen), S. Buson (Univ. of Wuerzburg) on behalf of the Fermi-LAT collaboration: We report an analysis of observations of the vicinity of the very high-energy IC181014A neutrino event (GCN 23338) 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 2018-10-14 11:52:46 UTC (T0) with J2000 position RA = 225.15 (-2.85,+1.40) deg, Decl. = -34.80 (-1.85,+1.15) deg 90% PSF containment. Two cataloged >100 MeV gamma-ray sources are located within the 90% IC181014A localization error. These are 3FGL J1457.4-3539 at a distance of roughly 1deg and associated with the flat-spectrum-radio-quasar PKS 1454-354, and 3FGL J1505.0-3432 at a distance of roughly 0.9deg and associated with the BL Lac object PMN J1505-3432 (Ackermann et al. 2015 ApJS 810, 14). Based on a preliminary analysis of the LAT data over the past month, neither of these two objects is detected in a high gamma-ray state. We searched for the existence of intermediate (months to years) timescale emission from a new gamma-ray transient source. Preliminary analysis indicates no significant (>5sigma) new excess emission (0.1 - 300 GeV) within the IC181014A 90% confidence localization. Assuming a power-law spectrum (photon index = 2.2 fixed) for a point source at the IceCube best-fit position, the >100 MeV flux upper limit (95% confidence) is < 4.5e-8 (< 2.74e-8) ph cm^-2 s^-1 for a 1-month (7-month) integration time before T0. Since Fermi normally operates in an all-sky scanning mode, regular monitoring of this source will continue. For this source the Fermi-LAT contact persons are T. Venters (tonia.m.venters at nasa.gov), S. Garrappa (simone.garrappa at desy.de) and S. Buson (e-mail: sara.buson at gmail.com). 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: 23340 SUBJECT: Search for counterparts to IceCube-181014A with IceCube DATE: 18/10/15 17:58:24 GMT FROM: Alex Pizzuto at ICECUBE/U of Wisconsin The IceCube Collaboration (http://icecube.wisc.edu/) reports: IceCube has performed a search for additional track-like muon neutrino events arriving from the direction of the IceCube-181014A alert (https://gcn.gsfc.nasa.gov/gcn3/23338.gcn3) in a time range of 2 days centered on the alert event time (2018-10-13 11:52:46 UTC to 2018-10-15 11:52:46 UTC) during which IceCube was collecting good quality data. Excluding the event that prompted the alert, two additional track-like events are found in spatial coincidence with the 90% PSF containment of IceCube-181014A. We find that these data are well described by atmospheric background expectations, with a p-value of 1.0. Accordingly, these tracks would represent a time-integrated muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 5.59 x 10^-4 TeV cm^-2 for this observation period. A subsequent search was performed to include the previous month of data (2018-09-14 11:52:46 UTC to 2018-10-15 11:52:46 UTC). In this case, we also report a p-value of 1.0, consistent with no significant excess of track events, and a corresponding time-integrated muon-neutrino flux upper limit assuming an E^-2 spectrum (E^2 dN/dE) at the 90% CL of 1.21 x 10^-1 TeV cm^-2. 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. [GCN OPS NOTE(16oct18): Per author's request, the "two additional neutrino track events are found in spatial coincidence with..." was changed to "two additional track-like events are found in spatial coincidence with...".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 23346 SUBJECT: Fermi GBM Observation of IceCube-181014A DATE: 18/10/17 20:37:56 GMT FROM: C. Michelle Hui at MSFC/Fermi-GBM B. Mailyan (UAH), P. Veres (UAH), P. Jenke (UAH), A. Goldstein (USRA), and C. M. Hui (MSFC) report on behalf of the Fermi GBM team: We have searched the Fermi Gamma-ray Burst Monitor data for a gamma-ray counterpart to IceCube-181014A (GCN 23338). The position was occulted by the Earth for Fermi at the time the neutrino was detected. GBM therefore cannot set any limits on impulsive emission. The ground-based untargeted search of GBM data did not find any candidates within +/- 1 hour of the event time. Measurements using the Earth Occultation technique around this position place a three sigma flux upper limit of about 190 mCrab for 12-100 keV between Oct 13th and Oct 15th.