GCN Circular 6771
Subject
GRB 070810b: Image Subtraction of Multiple Keck Observations
Date
2007-09-01T04:05:55Z (18 years ago)
From
Daniel Kocevski at UC Berkeley <kocevski@berkeley.edu>
D. Kocevski, J.S. Bloom, C. C. Thoene, and J. Prochaska report:
We performed image subtraction between multiple R-band observations
of the error box of short burst GRB070810b (Marshall et al., GCN
6743) with the Keck I telescope (+LRIS). The first epoch of
observations began at (UT) 2007-08-11 14:45:00 followed by a second
epoch six nights later at (UT) 2007-08-17 12:02:00, with equivalent
exposures of 630 and 900 seconds respectively. Image subtraction
using the public POIS-IPP package(*) software shows no variable
sources associated with the S1, S2 XRT positions (GCN 6754 , Starling
et al.) or the S3 position (Thoene et al., GCN 6756) nor any
significant residual sources within the BAT error circle down to a
limiting magnitude of ~25.5 mag in R band. The potential candidate
afterglow close to S2, reported by Pozanenko et al. can be resolved
as two objects in our images, which show no sign of variability
between the two epochs.
* See http://pan-starrs.ifa.hawaii.edu/project/IPP/software/