GCN Circular 34142
Subject
LVK S230619bd/GBM-230619: Upper limits from a two-week IceCube neutrino search
Date
2023-07-04T16:14:26Z (10 months ago)
From
Jessie Thwaites at IceCube/U Wisc-Madison <thwaites@wisc.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed an additional search for track-like muon neutrino events consistent with the sky localization of the joint skymap for low significance gravitational-wave candidate S230619bd and GBM-230619 (https://gcn.nasa.gov/circulars/34054) in a time range of -0.1 day, +14 days from the GW alert event time (2023-06-19 17:01:06.4 UTC to 2023-07-03 19:25:06.4 UTC). During this time period IceCube was collecting good quality data. This is a maximum likelihood analysis which searches for a generic point-like neutrino source coincident with the given GW skymap [1,2].
In this case, we report a p-value of 0.31, consistent with no significant excess of track events. IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino point sources within the locations spanned by the 90% spatial containment of the joint skymap ranges from 0.037 to 0.061 GeV cm^-2 in this time window.
A Bayesian search [1,2] was also performed, using the standard time window of 1000 seconds centered on the alert event time (2023-06-19 19:16:46 UTC to 2023-06-19 19:33:26 UTC), and using the the map for S230619bd circulated in the 2-Preliminary notice. This 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]. For this search we report a p-value of 0.22, consistent with no significant events coincident with the map. IceCube's sensitivity assuming an E^-2 spectrum (E^2 dN/dE) to neutrino point sources within the locations spanned by the 90% spatial containment of the 2-Preliminary map ranges from 0.0277 to 1.0771 GeV cm^-2 in a 1000 second time window.
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