{
  "submittedHow": "web",
  "bibcode": "2025GCN.41817....1I",
  "eventId": "LIGO/Virgo/KAGRA S250912s",
  "subject": "LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search",
  "circularId": 41817,
  "format": "text/plain",
  "createdOn": 1757708029967,
  "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 S250912s in a time range of 1000 seconds centered on the alert event time (2025-09-12 18:13:09 UTC to 2025-09-12 18:29:49 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\nTwo track-like events were found in spatial and temporal coincidence with the gravitational-wave candidate S250912s calculated from the map circulated in the S250912s-2-Preliminary notice. This represents an overall p-value of 0.00927 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-276.12 \t284.52 \t\t44.13 \t\t16.11 \t\t\t0.0115\n  19.10 \t275.72 \t\t24.65 \t\t 1.44 \t\t\t0.0530\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 individual p-value for the specific track event from this search.\n\nThe 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\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",
  "submitter": "Zsuzsa Marka at IceCube/Columbia University <zsuzsa@astro.columbia.edu>"
}