TITLE:   GCN CIRCULAR
NUMBER:  7374
SUBJECT: GRB 080307: Early RAPTOR Limits
DATE:    08/03/07 18:59:18 GMT
FROM:    James Wren at LANL  <jwren@nis.lanl.gov>

J. Wren, W.T. Vestrand, P.R. Wozniak, H. Davis
of Los Alamos National Laboratory report:

Our Raptor telescopes responded to Swift trigger 305011
(Holland et al., GCN 7362) at 11:24:30.8 UTC, 60.0 seconds
after the trigger and 7.3 seconds after receipt of the GCN
packet.  We detect no new optical source at the Swift XRT
position.  Five sigma limiting magnitudes are given for
three of our unfiltered response images in the table below.
Calibration was performed using the USNO B1.0 R-band
magnitudes.

T-start (UTC)           T-exp (s)    mag limit
-------------------------------------------------
2008-03-07 11:24:30.81    5            16.9
2008-03-07 11:25:53.96    10           17.3
2008-03-07 11:30:12.01    30           18.0