GCN Circular 25606
Subject
LIGO/Virgo S190901ap: Identification of a GW compact binary merger candidate
Date
2019-09-02T00:18:29Z (5 years ago)
From
Shasvath J. Kapadia at U. of Wisconsin, Milwaukee <kapadia@uwm.edu>
The LIGO Scientific Collaboration and the Virgo Collaboration report:
We identified the compact binary merger candidate S190901ap during
real-time processing of data from LIGO Livingston Observatory (L1) and
Virgo Observatory (V1) at 2019-09-01 23:31:01.838 UTC (GPS time:
1251415879.838). The candidate was found by the GstLAL [1] analysis
pipeline.
S190901ap is an event of interest because its false alarm rate, as
estimated by the online analysis, is 7e-09 Hz, or about one in 4
years. The event's properties can be found at this URL:
https://gracedb.ligo.org/superevents/S190901ap
The classification of the GW signal, in order of descending
probability, is BNS (86%), Terrestrial (14%), BBH (<1%), MassGap
(<1%), or NSBH (<1%).
Assuming the candidate is astrophysical in origin, there is strong
evidence for the lighter compact object having a mass < 3 solar masses
(HasNS: >99%). Using the masses and spins inferred from the signal,
there is strong evidence for matter outside the final compact object
(HasRemnant: >99%).
One sky map is available at this time and can be retrieved from the
GraceDB event page:
* bayestar.fits.gz, an updated localization generated by BAYESTAR
[2], distributed via GCN notice about 5 minutes after the candidate
For the bayestar.fits.gz sky map, the 90% credible region is 13613
deg2. Marginalized over the whole sky, the a posteriori luminosity
distance estimate is 242 +/- 81 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
<https://emfollow.docs.ligo.org/userguide/>.
[1] Messick et al. PRD 95, 042001 (2017)
[2] Singer & Price PRD 93, 024013 (2016)