Skip to main content
New Swift-BAT/GUANO and IceCube Notice Types Available! See news and announcements

GCN Circular 18626

Subject
LIGO/Virgo G194575: Updated significance from offline GW analysis
Date
2015-11-20T13:33:17Z (8 years ago)
From
Leo Singer at NASA/GSFC <leo.p.singer@nasa.gov>
The LIGO Scientific Collaboration and Virgo report:

The routine offline compact binary coalescence (CBC) analysis of the span
of data containing the gravitational-wave candidate G194575 (GCN 18442)
has completed. The offline CBC analysis consists of a pair of matched
filter search pipelines, gstlal and pycbc. They are similar to the
low-latency CBC searches that generate real-time alerts, but analyze the
data in discrete two-week chunks, are sensitive to both neutron star and
black hole binary mergers, use additional data quality vetoes, and employ
more live time to estimate the significance of candidates.

In our initial circular, we had reported the false alarm rate (FAR)
estimated by the low-latency gstlal search, 9.654e-08, or about 1/120
days. As estimated by the offline gstlal search, the candidate has a FAR
of 5.87e-06 Hz, or 1/1.97 days. As estimated by the offline pycbc
search, G194575 has a FAR of 8.19e-6 Hz, or 1/1.41 days.

Though the low-latency FAR estimate for this event met our threshold for
distribution of an alert, from the offline analysis we conclude that
G194575 is no longer an event of interest.
Looking for U.S. government information and services? Visit USA.gov