ABSTRACT
We present the first multi-wavelength follow-up observations of two candidate
gravitational-wave (GW) transient events recorded by LIGO and Virgo in their
2009–2010 science run. The events were selected with low latency by the network
of GW detectors (within less than 10 minutes) and their candidate sky locations
were observed by the Swift observatory (within 12 hr). Image
transient detection was used to analyze the collected electromagnetic data,
which were found to be consistent with background. Off-line analysis of the GW
data alone has also established that the selected GW events show no evidence of
an astrophysical origin; one of them is consistent with background and the other
one was a test, part of a “blind injection challenge.” With this work we
demonstrate the feasibility of rapid follow-ups of GW transients and establish
the sensitivity improvement joint electromagnetic and GW observations could
bring. This is a first step toward an electromagnetic follow-up program in the
regime of routine detections with the advanced GW instruments expected within
this decade. In that regime, multi-wavelength observations will play a
significant role in completing the astrophysical identification of GW sources.
We present the methods and results from this first combined analysis and discuss
its implications in terms of sensitivity for the present and future
instruments.
