GCN Circular 17312
Subject
GRB 150120A: P60 optical observations
Date
2015-01-20T04:06:55Z (10 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) and S. B. Cenko (NASA/GSFC) report:
The Palomar 60-inch robotic telescope began automatic follow-up of the
location of possibly-short GRB 150120A (D'Elia et al. GCN 17310)
starting at 2015-01-20 03:00:33 UT, approximately 2.7 minutes after the
GRB trigger. A sequence of rotating r, i, and z 60-second exposures was
acquired, followed by five 180-second exposures in each of r and i
bands, under good conditions.
No sources are clearly detected inside the enhanced XRT error circle
(Evans et al., GCN 17311), either in either individual exposures or in
stacks of all 60-second exposures taken in each filter (approximate UT
center time 15 minutes post-trigger, limiting magnitudes r>22.5, i>22.4,
z>20.9). We detect two faint sources slightly outside the error circle
in the stacked frames:
Source A: RA=00:41:16.55, dec=+33:59:42.87
Source B: RA=00:41:16.76, dec=+33:59:42.11
Both sources appear to be marginally detected in SDSS pre-imaging and we
do not yet have evidence of fading behavior. Further observations and
analysis are ongoing.
[GCN OPS NOTE(20jan15): Per author's request, the date in the third line
was changed from 2015-01-t0 to 2015-01-20.]