GRB 100305A VOEvent-triggered optical observations

[Bob Denny]

TITLE:   GCN CIRCULAR
NUMBER:  10475
SUBJECT: GRB 100305A Optical Observations
DATE:    10/03/05 14:57:01 GMT
FROM:    Arne A. Henden at AAVSO  <arne at aavso.org>

A. Henden (AAVSO), J. Gross (SRO), B. Denny (DC-3), D. Terrell (SwRI), and
W. Cooney (SRO) report:

We obtained imagery of the GRB 100305A burst reported by Troja et al.
(GCN 10470) using the Sonoita Research Observatory (SRO) 35cm telescope
in southern Arizona, utilizing an automatic VOevent trigger.  The
exposures began about 3 minutes after the burst and continued
for approximately two hours.  20 Rc-band, 10 V-band, and a set of
BVRI exposures for field calibration were acquired.
Inspection of the enhanced Swift-XRT position given by Osborne, et al.
(GCN 10474) does not show any optical afterglow to the following limits,
based on using star USNOB 1323-0268523 at 11:13:38.45 +42:23:45.7
as having magnitudes R=15.98 and V=16.67):

UTmid     delT    exp   filt  lim
(hrs)     (min)  (# x s)
09.1544  003.63  01x060  Rc  19.1
09.2379  008.64  10x060  Rc  20.5
09.4821  023.29  05x180  Rc  21.3
09.8411  044.83  05x300  Rc  21.6
10.8564  105.75  10x300  V   21.1

The AAVSO thanks the Curry Foundation for its support of the AAVSO
International High Energy Network.