GCN Circular 21657
Subject
LIGO/Virgo G298936: IceCube neutrino observations
Date
2017-08-23T14:12:33Z (8 years ago)
From
Stefan Countryman at LIGO Scientific Collaboration <stefan.countryman@ligo.org>
I. Bartos, S. Countryman (Columbia), C. Finley (U Stockholm), E. Blaufuss (U Maryland), R. Corley, Z. Marka, S. Marka (Columbia) on behalf of the IceCube Collaboration
In an analysis completed at 2017-08-23 13:41:57 UTC, we searched IceCube online track-like neutrino candidates (GFU) detected in a [-500,500] second interval about the LIGO-Virgo trigger G298936. We compared the candidate source directions of 8 temporally-coincident neutrinos to the BAYESTAR skymap, with the following parameters:
# dt[s] RA[deg] Dec[deg] E[TeV] Sigma[deg]
------------------------------------------------------------------
1. -398.00 226.9 -11.4 6.16 0.2
2. -172.94 84.3 19.3 0.99 0.9
3. -62.90 0.5 0.1 0.49 0.6
4. 155.56 36.5 39.7 0.82 0.7
5. 234.88 265.5 10.3 0.81 0.6
6. 263.89 174.4 23.7 1.61 3.4
7. 388.57 341.9 -26.9 15.35 0.2
8. 473.06 346.6 33.8 0.73 0.8
(dt--time from GW in [seconds]; RA/Dec--sky location in [degrees]; E--reconstructed secondary muon energy in [TeV]; Sigma--uncertainty of direction reconstruction in [degrees])
The analysis found NO COINCIDENT ONLINE TRACK-LIKE NEUTRINO CANDIDATES detected by IceCube within the 500 second window surrounding G298936 within the BAYESTAR skymap.
A coincident neutrino-GW skymap has been posted to GraceDB (<https://gracedb.ligo.org/apiweb/events/G298936/files/coinc_skymap_initial_icecube.png,0>). A JSON-formatted list of the above neutrinos can be downloaded from GraceDB at: <https://gracedb.ligo.org/apiweb/events/G298936/files/IceCubeNeutrinoList.json,0>
In addition, we are performing coincident searches with other IceCube data streams, including the high-energy starting events (HESE) and Supernova triggers. HESE events have typical energies > 60 TeV and start inside the detector volume, leading to a relatively pure event sample with a high fraction of astrophysical neutrinos. The SN trigger system is sensitive to sudden increases in photomultiplier counts across the detector, which could indicate a burst of MeV neutrinos. We will submit separate GCN circulars if coincident HESE or SN triggers are found.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. For a description of the IceCube realtime alert system, please refer to <http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1610.01814>; for more information on joint neutrino and gravitational wave searches, please refer to <http://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1602.05411>.