{
"subject": "LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches",
"bibcode": "2020GCN.27043....1I",
"createdOn": 1581568826000,
"circularId": 27043,
"submitter": "Raamis Hussain at IceCube ",
"email": "raamis.hussain@icecube.wisc.edu",
"body": "IceCube Collaboration (http://icecube.wisc.edu/) reports:\n\nSearches for track-like muon neutrino events detected by IceCube consistent\nwith the sky\nlocalization of gravitational-wave candidate S200213t in a time range of\n1000 seconds [1]\ncentered on the alert event time (2020-02-13 04:02:20.328 UTC to 2020-02-13\n04:19:00.328 UTC) have been performed.\nDuring this time period IceCube was collecting good quality data. Two\nhypothesis tests\nwere conducted. The first search is a maximum likelihood analysis which\nsearches for a\ngeneric point-like neutrino source coincident with the given GW skymap [2].\nThe\nsecond uses a Bayesian approach to quantify the joint GW + neutrino event\nsignificance, which\nassumes a binary merger scenario and accounts for known astrophysical\npriors in the\nsignificance estimate, such as GW source distance [3].\n\n1 track-like event is found in spatial and temporal coincidence with the\ngravitational-wave\ncandidate S200213t calculated from the map circulated in the 3-Initial\nnotice. This\nrepresents an overall p-value of 0.003 (2.75sigma) from the generic\ntransient search\nand an overall p-value of 0.0174 (2.11 sigma) for the Bayesian search.\nThese p-values\nmeasure the consistency of the observed track-like events with the known\natmospheric backgrounds.\n\nThe reported p-values can differ due to the estimated distance of the GW\ncandidate. The distance is used as a prior in Bayesian binary merger\nsearch, while it is not\ntaken into account in the generic transient point-like source search.\n\nProperties of the coincident events are shown below.\n\n dt ra dec Angular Uncertainty(deg) p-value(generic\ntransient) p-value(binary merger)\n-----------------------------------------------------------------------------------------------------\n -175.94 45.21 31.74 0.43 0.003\n 0.017\n\n\nwhere:\ndt = Time offset (sec) of track event with respect to GW trigger.\nAngular uncertainty = Angular uncertainty of track event: the radius of a\ncircle\n representing 90% CL containment by area.\nPvalue = the pvalue for this specific track event from each search.\n\n\nThe IceCube Neutrino Observatory is a cubic-kilometer neutrino detector\noperating at the\ngeographic South Pole, Antarctica. The IceCube realtime alert point of\ncontact can be\nreached at roc@icecube.wisc.edu\n\n\n[1] Baret et al., Astroparticle Physics 35, 1 (2011)\n[2] PoS(ICRC2019)918 Braun et al., Astroparticle Physics 29, 299 (2008)\n[3] Bartos et al. arXiv:1810.11467 (2018) and Countryman et\nal.arXiv:1901.05486 (2019)"
}