[vsnet-grb-info 4949] Four radio sources in Swift-XRT error box of GRB 070724

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6667
SUBJECT: Four radio sources in Swift-XRT error box of GRB 070724
DATE:    07/07/25 18:21:35 GMT
FROM:    Poonam Chandra at U Virginia/NRAO  <pc8s at virginia.edu>

Poonam Chandra (NRAO/UVA) and Dale A. Frail (NRAO) report on
behalf of the Caltech-NRAO-Carnegie GRB Collaboration:


"We used the Very Large Array to observe the field of view toward
GRB 070724 (GCN 6654) at a frequency of 8.46 GHz on 2007 July 25th
at 12.50 UT, 25.4 hours after the burst. Owing to VLA A-array observation,
we obtained excellent resolution of 0.33"x0.24". We find four possible
sources in the Swift-XRT error box, which are above 3-sigma. These are

     Position (J2000)                           Flux density (Jy)

1:   RA 01 51 14.105    +/-  0.002         4.3899E-04 +/-  8.40E-05
     DEC -18 35 45.938  +/-  0.024

2:   RA 01 51 14.125    +/-  0.002         4.0976E-04 +/-  8.51E-05
     DEC -18 35 41.404  +/-  0.021

3:   RA 01 51 13.824    +/-  0.003         3.1155E-04 +/-  8.48E-05
     DEC -18 35 36.626  +/-  0.033

4:   RA 01 51 14.104    +/-  0.003         3.1204E-04 +/-  8.47E-05
     DEC -18 35 40.626  +/-  0.030

Here source 4 is closest to Josh Bloom's blue source (GCN 6658) with
offset of 1.7 arcsec. Source 2 is closest to P60 afterglow position of the
GRB (Cenko et al. GCN 6664) with offset of 1.3 arcsec.

NVSS does not show any radio source around this position.
More observations are planned to see the variability of these sources.


The National Radio Astronomy Observatory is a facility of the National
Science Foundation operated under cooperative agreement by Associated
Universities, Inc."