TITLE: GCN CIRCULAR
NUMBER: 26202
SUBJECT: LIGO/Virgo S191109d: Identification of a GW compact binary merger candidate
DATE: 19/11/09 01:50:16 GMT
FROM: Brandon Piotrzkowski at U of Wisconsin-Milwaukee
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We identified the compact binary merger candidate S191109d during
real-time processing of data from LIGO Hanford Observatory (H1) and
LIGO Livingston Observatory (L1) at 2019-11-09 01:07:17.221 UTC (GPS
time: 1257296855.221). The candidate was found by the SPIIR [1], CWB
[2], GstLAL [3], MBTAOnline [4], and PyCBC Live [5] analysis
pipelines.
S191109d is an event of interest because its false alarm rate, as
estimated by the online analysis, is 1.5e-13 Hz, or about one in 2e5
years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S191109d
The classification of the GW signal, in order of descending
probability, is BBH (>99%), Terrestrial (<1%), BNS (<1%), NSBH (<1%),
or MassGap (<1%).
Assuming the candidate is astrophysical in origin, the probability
that the lighter compact object has a mass < 3 solar masses (HasNS) is
<1%. Using the masses and spins inferred from the signal, the
probability of matter outside the final compact object (HasRemnant) is
<1%.
One sky map is available at this time and can be retrieved from the
GraceDB event page:
* “bayestar.fits.gz,0”, an initial localization generated by BAYESTAR
[6], distributed via GCN notice about 9 minutes after the candidate
event time.
For the bayestar.fits.gz,0 sky map, the 90% credible region is 1487
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 1810 +/- 604 Mpc (a posteriori mean +/- standard
deviation).
For further information about analysis methodology and the contents of
this alert, refer to the LIGO/Virgo Public Alerts User Guide
.
[1] Qi Chu, PhD Thesis, The University of Western Australia (2017)
[2] Klimenko et al. PRD 93, 042004 (2016)
[3] Messick et al. PRD 95, 042001 (2017)
[4] Adams et al. CQG 33, 175012 (2016)
[5] Nitz et al. PRD 98, 024050 (2018)
[6] Singer & Price PRD 93, 024013 (2016)