[vsnet-grb-info 23093] LIGO/Virgo S190728q: One neutrino candidate from IceCube search

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25192
SUBJECT: LIGO/Virgo S190728q: One neutrino candidate from IceCube search
DATE:    19/07/28 10:06:18 GMT
FROM:    Raamis Hussain at IceCube  <raamis.hussain at icecube.wisc.edu>

IceCube Collaboration (http://icecube.wisc.edu/) reports:

A search for track-like muon neutrino events detected by IceCube consistent
with the sky
localization of gravitational-wave candidate S190728q in a time range of
1000 seconds [1]
centered on the alert event time (2019-07-28 06:36:50.529 UTC to 2019-07-28
06:53:30.529 UTC)
has been performed. During this time period IceCube was collecting good
quality data.
The search is a maximum likelihood analysis which searches for a generic
point-like neutrino
 source coincident with the given GW skymap [2].

One track-like event is found in spatial and temporal coincidence with the
gravitational-wave
candidate S190728q calculated from the map circulated in the 4-Initial
notice. This
represents an overall p-value of 0.03 (1.84 sigma).

An earlier search (GCN 25185) based on preliminary information of S190728q
yielded no significant
p-values for the worse GW localization [3].


Properties of the coincident events are shown below.

  dt        ra (deg)        dec (deg)    Angular Uncertainty(deg)
 p-value(generic transient)
----------------------------------------------------------------------------------------------
 -360      312.87             5.85                    4.81
     0.039


where:
dt = Time offset (sec) of track event with respect to GW trigger.
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
RA & Dec = Right ascension and declination in degrees quoted in J2000 epoch

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 at icecube.wisc.edu


[1] Baret et al., Astroparticle Physics 35, 1 (2011)
[2] Braun et al., Astroparticle Physics 29, 299 (2008)
[3] GCN 25185: https://gcn.gsfc.nasa.gov/gcn3/25185.gcn3