[vsnet-grb-info 22404] LIGO/Virgo S190512at: Identification of a GW compact binary merger candidate

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  24503
SUBJECT: LIGO/Virgo S190512at: Identification of a GW compact binary merger candidate
DATE:    19/05/12 19:05:01 GMT
FROM:    Deep Chatterjee at University of Wisconsin, Milwaukee  <deep at uwm.edu>

The LIGO Scientific Collaboration and the Virgo Collaboration report:


We identified the compact binary merger candidate S190512at during

real-time processing of data from LIGO Hanford Observatory (H1), LIGO

Livingston Observatory (L1), and Virgo Observatory (V1) at 2019-05-12

18:07:14.422 UTC (GPS time: 1241719652.422). The candidate was found

by the PyCBC Live [1], CWB [2], GstLAL [3], MBTAOnline [4], and spiir

[5] analysis pipelines.


S190512at is an event of interest because its false alarm rate, as

estimated by the online analysis, is 1.9e-09 Hz, or about one in 16

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


https://gracedb.ligo.org/superevents/S190512at


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, 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 skymap is available at this time and can be retrieved from the

GraceDB event page:

* bayestar.fits.gz, an updated localization generated by BAYESTAR

[6], distributed via GCN notice about 53 minutes after the candidate.


For the bayestar.fits.gz skymap, the 90% credible region is 399 deg2.

Marginalized over the whole sky, the a posteriori luminosity distance

estimate is 1331 +/- 341 Mpc (a posteriori mean +/- standard

deviation).


No Preliminary Notice was sent for this event due to a technical problem.


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/><https://emfollow.docs.ligo.org/userguide/>.


[1] Nitz et al. PRD 98, 024050 (2018)

[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] Qi Chu, PhD Thesis, The University of Western Australia (2017)

[6] Singer & Price PRD 93, 024013 (2016)