TITLE: GCN CIRCULAR NUMBER: 34953 SUBJECT: LIGO/Virgo/KAGRA S231106y: one counterpart neutrino candidate from IceCube neutrino searches DATE: 23/11/06 16:07:24 GMT FROM: Erik Blaufuss at University of Maryland, College Park The IceCube Collaboration (http://icecube.wisc.edu/) reports: A search for track-like muon neutrino events detected by IceCube consistent with the sky localization of the low-significance gravitational wave candidate S231106y in a time range of 1000 seconds centered on the alert event time (2023-11-06 06:48:08 UTC to 2023-11-06 07:04:48 UTC) has been performed [1,2]. During this time period IceCube was collecting good quality data. One hypothesis test was conducted for this low-significance gravitational wave event. The search uses 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 significance estimate [3]. One track-like event was found in spatial and temporal coincidence with the gravitational-wave candidate S231106y calculated from the map circulated by LVK as S231106y-2-Preliminary. This represents an overall pre-trial p-value of 0.0090 for the Bayesian search. The reported p-value here does not account for any trials correction (multiple hypotheses testing). The false alarm rate of this coincidence can be obtained by multiplying the p-value with the corresponding GW trigger rate. Further details are available at https://gcn.nasa.gov/missions/icecube and at https://roc.icecube.wisc.edu/public/LvkNuTrackSearch. . Properties of the coincident event(s) are shown below. dt(s) RA(deg) Dec(deg) Angular uncertainty(deg) p-value(generic transient) p-value(Bayesian) ----------------------------------------------------------------------------------------------------- 41.78 318.15 69.01 6.54 not applicable 0.0090 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 each 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