{
  "submittedHow": "web",
  "format": "text/plain",
  "bibcode": "2025GCN.41657....1I",
  "eventId": "LIGO/Virgo/KAGRA S250902av",
  "body": "IceCube Collaboration (http://icecube.wisc.edu/) reports:\n\nWe have performed a search for track-like muon neutrino candidate events detected by IceCube consistent with the sky localization of the low-significance gravitational-wave candidate event S250902av in a time range of 1000 seconds centered on the alert event time (2025-09-02T07:01:18.83 UTC to 2025-09-02T07:17:58.83 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].  \n\nOne track-like event was found in spatial and temporal coincidence with the gravitational-wave candidate S250902av calculated from the map circulated in the S250902av-2-Preliminary notice. This represents an overall p-value of 5.1e-03 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). \n\nFurther details are available at https://gcn.nasa.gov/missions/icecube and at https://roc.icecube.wisc.edu/public/LvkNuTrackSearch.\n\nProperties of the coincident event are shown below:\n\n dt(s)     RA(deg)       Dec(deg)    Angular uncertainty(deg)  p-value(Bayesian)\n-------------------------------------------------------------------------------------\n 134.47    15.51\t   24.37            \t1.54\t\t\t0.00533\n\nwhere:\ndt = Time of track event minus time of GW trigger (sec)\nAngular uncertainty = Angular uncertainty of track event: the radius of a circle \n     representing 90% CL containment by area.\np-value = the p-value for this specific track event from this search.\n\nThe IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the \ngeographic South Pole, Antarctica. The IceCube realtime alert point of contact can be \nreached at roc@icecube.wisc.edu\n\n[1] M. G. Aartsen et al 2020 ApJL 898 L10\n[2] Abbasi et al. Astrophys.J. 944 (2023) 1, 80\n[3] I. Bartos et al. 2019 Phys. Rev. D 100, 083017\n",
  "subject": "LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search",
  "createdOn": 1756818665409,
  "submitter": "Erik Blaufuss at University of Maryland, College Park <blaufuss@umd.edu>",
  "circularId": 41657
}