TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1952
SUBJECT: GRB030323, ROTSE-III detection of possible optical counterpart
DATE:    03/03/24 21:15:18 GMT
FROM:    Don Smith at U michigan  <dasmith@rotse2.physics.lsa.umich.edu>

Smith, D. A. & Rykoff E. S. on behalf of the ROTSE collaboration report:

We have observed the full error box of GRB 030323 (HETE trigger 2640) using the
ROTSE-3B 0.45 meter telescope at McDonald Observatory, Texas, starting March
24, 5:47 UT (7.8 hours after the burst).  Ninety one-minute unfiltered
exposures were taken, yielding limiting magnitudes between 17.5 and 18.5,
calibrated against USNO A2.0 R-band.  A source is marginally detected in seven
of these images at the location of the optical counterpart candidate reported
by Gilmore et al.  (GCN Circ. 1949).  We co-added four consecutive sets of
twenty images, and the counterpart candidate is clearly detected in the first
co-added image at a magnitude of 18.4+-0.1 at 5:59 hours UT (limiting magnitude
for this co-added image is estimated at 19.5).  Visual inspection of the other
three co-added images indicate that the source is present near the limiting
magnitude in each frame, and we will continue analysis to derive a light curve.

Images and light curves will soon be available at http://www.rotse.net