TITLE:   GCN CIRCULAR
NUMBER:  10533
SUBJECT: GRB 100316D: ATCA radio observations
DATE:    10/03/20 15:52:22 GMT
FROM:    Alicia Soderberg at Harvard/CfA  <asoderbe@cfa.harvard.edu>

Mark Wieringa (CSIRO), Alicia Soderberg (Harvard/CfA), and Phil Edwards
(CSIRO) report:

"We observed the field of GRB 100316D (Stamatikos et al. GCN 10496) with
the Australia Telescope Compact Array beginning on Mar 18.35 for 3.5 hrs.
Data were collected at central frequencies of 5.4 and 9.0 GHz with 2 GHz
bandwidth each.  We do not detect any radio sources within the refined
XRT error circle (Starling et al. GCN 10519).  We place upper
limits of 104 microJy at 5.4 GHz and 165 microJy at 9.0 GHz (4 sigma).
At the redshift of the host galaxy (z=0.059; Vergani et al. GCN 10512),
these limits imply a radio spectral luminosity below 8e+27 erg/s/Hz
which is a factor of 2 to 10 lower than the radio afterglow luminosities
observed for nearby long-duration GRBs 980425 (Kulkarni et al. 1998),
031203 (Soderberg et al. 2004), and 060218 (Soderberg et al. 2006) on
comparable timescales.  Further observations are planned."