TITLE:   GCN CIRCULAR
NUMBER:  26235
SUBJECT: LIGO/Virgo S191110af: Upper limits from IceCube MeV neutrino searches
DATE:    19/11/11 23:39:39 GMT
FROM:    Erik Blaufuss at U. Maryland/IceCube  <blaufuss@umd.edu>

The IceCube Collaboration (http://icecube.wisc.edu/) has investigated the possibility that gravitational wave candidate S191110af is a burst 
event consistent with a core-collapse supernova in the Milky Way.  

IceCube can detect the O(10 MeV) neutrinos from a core-collapse supernova by searching for correlated increases in the hit rates of 
photosensors in the detector during the 10-second duration of the associated neutrino burst [1,2]. IceCube is primarily sensitive to 
inverse beta decay events produced by electron antineutrinos from the accretion phase of the supernova, and can observe a core-collapse 
event at any location in the Milky Way independent of the mass of the stellar progenitor [2].  

Two triggers in the IceCube MeV neutrino detection system bracket the time of the gravitational wave alert: one at 2019-11-10 16:21:11 and 
one at 2019-11-11 00:20:47. Both triggers are consistent with background fluctuations which occur at a false alarm rate of about 5/day.

Using the non-detection of a correlated increase in the hit rates in IceCube, we estimate the total energy emitted into neutrinos from the gravitational 
wave candidate to be

E < 6.5e50 erg * (d / 10 kpc)**2 * (15 MeV / E_avg)**2,

at 90% confidence, with d giving the distance to the burst and E_avg the average energy of emitted neutrinos.

The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole in Antarctica. 
The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu.

[1] R. Abbasi et al., Astronomy and Astrophysics 535, A109 (2011).
[2] R. Cross, A. Fritz, S. Griswold, PoS(ICRC2019) 889, arXiv:1908.07249 (2019).