[vsnet-grb-info 5108] GRB 070920b, SMARTS optical observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6814
SUBJECT: GRB 070920b, SMARTS optical observation
DATE:    07/09/21 18:11:29 GMT
FROM:    Bethany Cobb at Yale U  <cobb at astro.yale.edu>

B. E. Cobb, part of the larger SMARTS consortium, reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical imaging of the error region of GRB 070920b
(Racusin et al. GCN 6808) with a mid-exposure time of ~4.4 hours
post-burst (2007-09-21 01:29 UT).  The total summed exposure
time amounted to 36 minutes in I, but images were taken under poor
weather conditions.

Comparison to the DSS reveals no new sources in the
refined GRB error region (Barthelmy et al. GCN 6811).
Our I-band limiting magnitude is I~20.8 (calibrated using
several USNO-B1.0 stars).