Chandra observations of radio transients

The observations reach a limiting sensitivity of ~10^-4^counts/s, corresponding to a flux of a few times 10^-15^erg/s/cm^2^ for the models we explore. The Chandra observations were undertaken to search for X-ray counterparts to the eight transient sources without optical counterparts, and the two transient sources with optical counterparts seen by Bower et al. Neither of the sources with optical counterparts was detected in X-rays.

One of the eight optical non-detections is associated with a marginal (2.4{sigma}) X-ray detection in our Chandra image. A second optically undetected Bower et al. transient may be associated with a z=1.29 X-ray-detected quasar or its host galaxy, or alternatively is undetected in X-rays and is a chance association with the nearby X-ray source. The X-ray flux upper limits, and the one marginal detection, are consistent with the interpretation of Ofek et al. (2010ApJ...711..517O) that the optically undetected radio transients are flares from isolated old Galactic neutron stars.