Poonam Chandra1 and Dale A. Frail2
Abstract.
In this paper, we review the afterglow properties of 304 Gamma
Ray Bursts observed with various
radio telescopes between the year 1997 to January
2011. Most of the observations in the sample presented here were
performed in the 8.5 GHz band with the Very Large Array.
Our sample shows that the detection rate
for the radio afterglows has stayed at about 31% for the
pre-Swift as well as the post-Swift bursts, in
contrast to large increases in the optical and X-ray afterglow
detection rates. Our detailed analysis of the detected versus the
non-detected radio afterglows shows that these are severely limited
by the instrument sensitivity. We also find that there is no obvious
correlation between the radio luminosity with the isotropic
γ-ray energy release, the γ-ray fluence, or with the
X-ray flux;
however, the optical afterglows fluxes show a weak correlation with
the radio flux density. Radio afterglow detection is dependent upon
a relatively narrow range of circumburst densities (1-10 cm-3)
and microscopic shock parameters, especially the magnetic energy
density. Finally we discuss the most interesting bursts and
some of the interesting current topics in the GRB field.
Keywords: gamma-ray burst: general -- hydrodynamics--radio continuum: general
1Department of Physics, Royal Military College of Canada, Kingston, ON K7M3C9, Canada
2National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801, USA