GCN Circular 6356
Subject
GRB 070429: ROTSE-III Optical Limits
Event
Date
2007-04-29T01:57:07Z (19 years ago)
From
Eli Rykoff at U of Michigan/ROTSE <erykoff@umich.edu>
E.S. Rykoff (U Mich), B. E. Schaefer (Louisiana State), H. Swan (U
Mich), report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,
responded to GRB 070429 (Swift trigger 277571, GCN 6355, Barthelmy, et
al), producing images beginning 6.7 s after the GCN notice time. An
automated response took the first image at 01:36:46.7 UT, 96.6 s after
the burst, under good conditions. We took 10 5-sec, 10 20-sec exposures;
imaging is ongoing. These unfiltered images are calibrated relative to
USNO A2.0 (R).
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma BAT error circle or the XRT error circle, for both single images
and coadding into sets of 10; however, we are limited as the field is
somewhat crowded. Individual images have limiting magnitudes ranging
from 16.1-17.1; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
01:36:46.7 01:36:51.7 5 16.2 96.6 N
01:36:46.7 01:38:04.4 77 17.3 96.6 Y
01:38:19.4 01:43:08.1 288 18.0 189.3 Y