GCN Circular 325
Subject
GRB 990510: optical observation
Date
1999-05-14T00:45:00Z (26 years ago)
From
Gabriele Ghisellini at Obs.Astro. di Brera <gabriele@merate.mi.astro.it>
D. Lazzati, S. Covino and G. Ghisellini, of the Observatory of Brera
(Milan, Italy) report:
In the 600 s VLT-FORS1 image taken at May 11.13509 with 1.2" seeing, the
faint source 2.1" south of the OT of GRB990510 is completely consistent
with being a pointlike object, 2.86+-0.02 mag (in the R band) fainter
than the source located 3.9" north, 0.8" west of the OT.
At this time the latter source and the OT had the same magnitude,
R=19.10+-0.02 (assuming R=16.5 for the USNO star at RA = 13:38:00.82,
DEC=-80:29:11.7).
This suggests that the faint source is not the host galaxy of the GRB.
See in http://www.merate.mi.astro.it/~lazzati/GRB990510/ the original
image, the image with the OT subtracted, and the residuals after having
subtracted also the faint object, assuming it is a point source.
This message is citeable.