GCN Circular 2650
Subject
GRB 040812: Optical counterparts of CXO sources
Date
2004-08-18T17:45:40Z (20 years ago)
From
Edo Berger at Caltech <ejb@astro.caltech.edu>
E. Berger (Carnegie Observatories) reports on behalf of a larger
collaboration:
"We inspected the positions of Chandra sources CXO 1-7 (GCN #2648),
detected in the error circle of GRB 040812 (GCN #2640), in our Keck LRIS
and Las Campanas Du Pont 2.5-m I-band images (GCN #2645):
CXO# RA Dec Counterpart?
---------------------------------------------------
1 16 26 00.47 -44 41 22.6 star
2 16 26 02.25 -44 43 49.4 ---- *
3 16 26 06.48 -44 43 20.8 star
4 16 26 08.44 -44 41 25.2 none **
5 16 25 54.65 -44 42 49.4 star/galaxy
6 16 25 58.73 -44 41 47.0 star/galaxy
7 16 26 1.21 -44 42 46.6 star
* CXO-2 is located about 20" away from a very bright star, and this
position is saturated in all of our images
** CXO-4 is located about 2" away from a galaxy/star
In addition, none of the optical counterparts (excluding CXO-2) exhibit
any significant variability either between the two Keck epochs (taken 47
and 104 minutes after the burst) or between the Keck and LCO observations
(taken 1.75 days after the burst)."