TITLE: GCN CIRCULAR NUMBER: 35365 SUBJECT: LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search DATE: 23/12/15 22:31:26 GMT FROM: acz2122@columbia.edu IceCube Collaboration (http://icecube.wisc.edu/) reports: We have performed a search for track-like muon neutrino events detected by IceCube consistent with the sky localization of the low-significance gravitational-wave candidate event S231215i in a time range of 1000 seconds centered on the alert event time (2023-12-15T02:22:01 UTC to 2023-12-15T02:38:41 UTC) [1,2]. During this time period IceCube was collecting good quality data. A single hypothesis test was conducted using a Bayesian approach to quantify the joint GW + neutrino event significance, which assumes a binary merger scenario and accounts for known astrophysical priors, such as GW source distance, in the statistical significance estimation [3]. Three track-like events are found in spatial and temporal coincidence with the gravitational-wave candidate S231215i calculated from the map circulated in the S231215i-2-Preliminary notice, although not in coincidence with each other. This represents an overall p-value of 0.0039 for the Bayesian search. The p-value measures the consistency of the observed track-like events with the known atmospheric backgrounds for this single map (not accounting for statistical trials from multiple GW events). Further details are available at https://gcn.nasa.gov/missions/icecube and at https://roc.icecube.wisc.edu/public/LvkNuTrackSearch. Properties of the coincident events are shown below: dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value(Bayesian) ------------------------------------------------------------------------------------- -199.53 311.05 +33.46 2.774 0.0063 -153.98 223.68 +7.51 1.723 0.0304 -322.42 220.21 +25.97 1.374 0.0398 where: dt = Time of track event minus time of GW trigger (sec) Angular uncertainty = Angular uncertainty of track event: the radius of a circle representing 90% CL containment by area. p-value = the p-value for this specific track event from this search. 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] M. G. Aartsen et al 2020 ApJL 898 L10 [2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80 [3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017 View this GCN Circular online at https://gcn.nasa.gov/circulars/35365. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...