GCN Circular 3994
Subject
GRB 050915b, SMARTS optical/IR observations of the XRT position
Event
Date
2005-09-16T23:09:33Z (21 years ago)
From
Bethany Cobb at Yale U <cobb@astro.yale.edu>
B. E. Cobb and C. D. Bailyn (Yale), part of the larger SMARTS
consortium, report:
Our ANDICAM observations reported in GCN 3988 were re-examined
following the detection of the X-ray afterglow of GRB 050915b (GCN 3989,
Falcone et al.). The position of the X-ray afterglow was captured in both
our optical and IR images.
Three sources are detected within the X-ray afterglow error region:
RA DEC
A) 14:36:26.04 -67:24:41.4
B) 14:36:26.35 -67:24:32.2
C) 14:36:27.30 -67:24:39.3
The first source (A) has a stellar profile and has previously been clearly
detected in both the SDSS and 2MASS surveys. The other two sources (B and C)
appear only slightly above the detection limits of our ANDICAM images.
Sources B and C are also weakly detected in the SDSS (and possibly in 2MASS).
These two sources, particularly source B, might be extended, though this is
uncertain due to the low significance of their detection.
The brightness of these sources does not vary significantly over our
period of observation.
Total summed exposure times amounted to 30 minutes in I and V and
24 minutes in J and K, with a mid-exposure time of 2005-09-15 00:01 UT
(~2.6 hours post-burst). The preliminary limiting magnitudes of our
images are as follows:
V < 21.4 +/- 0.1
I < 21.3 +/- 0.1
J < 18.3 +/- 0.2
K < 17.8 +/- 0.2