Radio Remnants of Compact Binary Mergers
The question ``what is the observable electromagnetic (EM) signature of a compact binary
merger?" is an intriguing one with crucial consequences to the quest for gravitational
waves (GW). Compact binaries (Neutron star - Neutron star, NS-NS, or Black Hole -
Neutron star, BH-NS) are the prime candidates sources for gravitational radiation
emission. A detection of an electromagnetic signal accompanying a low significance
gravitational radiation signal would confirm the discovery, thereby increasing the GW
detectors sensitivity. Even before the advanced version of these detectors become
operational an electromagnetic detection would provide a reliable estimate of the
(presently highly uncertain) rate of these events. This is of substantial importance for
the design and the operational strategy of the advanced detectors.
Building on the theory and observations of radio supenovae we show that matter ejected
from a merger would produce a long lasting (typically a month) rather strong (a few
mJy) radio remnant. Future al sky radio surveys could detect a few dozen such remnants
in any give time. Detailed followup radio observations could easily reveal such a
remnant up to the advanced LIGO-Virgo's detection horizon.