GCN Circular 3256
Subject
GRB 050412: optical limit
Date
2005-04-13T19:04:59Z (19 years ago)
From
Weidong Li at UC Berkeley KAIT/LOSS <weidong@astron.berkeley.edu>
W. Li, R. Chornock, S. Jha, and A. V. Filippenko (University of
California, Berkeley) report:
"The Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory
robotically observed Swift GRB 050412 (Trigger #114485; Cummings et
al., GCN 3237). The first 3x15s grid image started at 05:45:09.0 UT
(66s after the burst), but it was not useful due to a technical
problem. Subsequent images have varying exposure times from 15s to
360s, and were observed with R, I, V, and z filters. Within the refined
XRT error circle (Mangano et al., GCN 3253) we did not detect any sources.
Our first useful 15s R-band exposure started at 05:45:53 UT (110s after
the burst) has a limiting magnitude of 17.5 when compared to the USNO
A2.0 caltalog. A 360s R-band exposure started at 06:12:02 UT has a
limiting magnitude of 19.6.
One of us (WL) also took two R-band images with the 1.0-m Nickel
telescope at Lick Observatory: one 1200s exposure started at 07:56:49
UT and the other 600s exposure started at 08:18:03 UT. The combined
image did not detect a source within the XRT error circle to a limiting
mag of about 21. "