GCN Circular 24922

The LIGO Scientific Collaboration and the Virgo Collaboration report:



We identified the compact binary merger candidate S190630ag during

real-time processing of data from LIGO Livingston Observatory (L1) and

Virgo Observatory (V1) at 2019-06-30 18:52:05.180 UTC (GPS time:

1245955943.180). The candidate was found by the GstLAL [1] analysis

pipeline.


S190630ag is an event of interest because its false alarm rate, as

estimated by the online analysis, is 1.4e-13 Hz, or about one in 1e5

years. The event's properties can be found at this URL:


https://gracedb.ligo.org/superevents/S190630ag


The classification of the GW signal, in order of descending

probability, is BBH (94%), MassGap (5%), NSBH (<1%), Terrestrial

(<1%), or BNS (<1%).


Assuming the candidate is astrophysical in origin, there is strong

evidence against the lighter compact object having a mass < 3 solar

masses (HasNS: <1%). Using the masses and spins inferred from the

signal, there is strong evidence against matter outside the final

compact object (HasRemnant: <1%).


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 3 minutes after the candidate


The preferred sky map at this time is bayestar.fits.gz, with 90% credible

region of 8493 deg2. Marginalized over the whole sky, the a posteriori

luminosity distance estimate is 1059 +/- 307 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)