[vsnet-grb-info 16523] GRB 150424A: 9.8 GHz VLA detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17804
SUBJECT: GRB 150424A: 9.8 GHz VLA detection
DATE:    15/05/07 17:03:52 GMT
FROM:    Wen-fai Fong at U of Arizona  <wfong at email.arizona.edu>

W. Fong (Univ. of Arizona) reports:

"We observed the position of the short-duration GRB 150424A (Beardmore et
al., GCN 17743) with the Karl G. Jansky Very Large Array (VLA) beginning on
2015 Apr 25.073 UT (18.02 hr post-burst) at a mean frequency of 9.8 GHz. In
1 hour of observations, we detect a faint radio source at the position:

RA(J2000) = 10:09:13.37
Dec(J2000) = -26:37:51.49

with an uncertainty of 0.5" in each coordinate. This position is coincident
with the position of the X-ray afterglow (Goad et al., GCN 17749) as well
as the position of the optical afterglow (Perley and McConnell., GCN 17745;
Malesani et al., GCN 17756; Kann et al., GCN 17757; Butler et al., GCN
17762).

We measure a 9.8 GHz flux density of ~31 microJy. To assess the nature of
this radio source, we obtained two additional sets of VLA observations
starting at 4.67 and 7.88 days after the burst. The source is no longer
detected in each of these observations, as well as a deep, combined image,
to 3-sigma limits of 29 microJy and 20 microJy, respectively.

Due to the fading of the radio source, as well as the positional
coincidence with the X-ray and optical afterglows, we consider this source
to be the radio afterglow of GRB 150424A.

We thank the VLA staff for quickly executing these observations."