GCN Circular 9622
Subject
GRB 090708: ROTSE-III Optical Limits
Date
2009-07-08T03:58:49Z (15 years ago)
From
Fang Yuan at ROTSE <yuanfang@umich.edu>
F. Yuan (U Mich), E.S. Rykoff (UCSB), H. Flewelling (IfA/Hawaii), T.
Guver (U Arizona), S. B. Pandey (U Mich), W. Rujopakarn (Steward),
report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
090708 (Swift trigger 356776; Krimm et al., GCN 9621), producing
images beginning 7.4 s after the GCN notice time. An automated
response took the first image at 03:39:04.5 UT, 49.2 s after the
burst, under fair conditions. We took 10 5-sec, 10 20-sec and 10 60-
sec exposures. These unfiltered images are calibrated relative to USNO
A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle, for both single images and coadding
into sets of 10. Individual images have limiting magnitudes ranging
from 14.8-16.1; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
03:39:04.5 03:39:09.5 5 15.0 49.2 N
03:39:04.5 03:40:11.6 67 16.6 49.2 Y
03:40:27.8 03:45:35.8 308 17.4 132.5 Y