TITLE:   GCN CIRCULAR
NUMBER:  38805
SUBJECT: GRB 250103B: LCOGT Optical Upper Limit
DATE:    25/01/03 19:44:52 GMT
FROM:    Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>

R. Strausbaugh (Eastern Illinois University), A. Cucchiara (NASA) report on behalf of a larger collaboration:

We observed the Swift GRB 250103B field (Eyles-Ferris et al., GCN 38796)  with the LCOGT 1-meter Sinistro instrument at the South African Astronomical Observatory site, on January 3, from 18:51 to 19:23 UT (corresponding to 4.12 to 4.65 hours after the GRB trigger time) with the Bessel I and R filters.

We performed a series of 3x300s exposures in I-band and R-band.  We do not detect a source within the  XRT error region in either band.

The following 5-sigma upper limits are calculated using the USNO-B1.0 catalog as reference:

R > 23.0
I > 22.1

These magnitudes are not corrected for galactic extinction.