Electromagnetic follow-up of gravitational wave transient signal   candidates
  Pioneering efforts aiming at the development of multi-messenger gravitational wave and electromagnetic astronomy have been made. An electromagnetic observation follow-up program of candidate gravitational wave events has been performed (Dec 17 2009 to Jan 8 2010 and Sep 4 to Oct 20 2010) during the recent runs of the LIGO and Virgo gravitational wave detectors. It involved ground-based and space electromagnetic facilities observing the sky at optical, X-ray and radio wavelengths. The joint gravitational wave and electromagnetic observation study requires the development of specific image analysis procedures able to discriminate the possible electromagnetic counterpart of gravitational wave triggers from contaminant/background events. The paper presents an overview of the electromagnetic follow-up program and the image analysis procedures. 
M. Branchesi (for the LIGO Scientific Collaboration and for the Virgo   Collaboration)
astro-ph.IM astro-ph.HE