[vsnet-grb-info 7991] GRB 090618 15GHz radio detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9532
SUBJECT: GRB 090618 15GHz radio detection
DATE:    09/06/19 09:50:32 GMT
FROM:    Guy Pooley at MRAO, Cambridge, UK  <ggp1 at cam.ac.uk>

Guy Pooley (Cavendish Astrophysics, U. Cambridge) reports on behalf 
of the AMI collaboration:

The AMI Large Array (the rebuilt Ryle Telescope) was used to observe 
the field of GRB 090618 (Schady et al, GCN9512) on 2009 June 19 
from 02h45m to 05h45m UT (18.25 to 21.25h after the burst) 
using the position from Cenko et al (GCN9213). 
The observing band was 14.6 to 17.5 GHz and the rms noise 85 microJy. 
The angular resolution is approx. 50" x 20".

We make a clear detection of a source at the position of the GRB
with a flux density 550 microJy. A split of the data suggests that 
the flux density increased from 425 to 640 microJy between the
first and second halves of the observation, but this is barely 
statistically significant. 

There is no radio source visible at that position in the NVSS (1.4GHz).

This report may be quoted in publications.