GCN Circular 38805
Subject
GRB 250103B: LCOGT Optical Upper Limit
Date
2025-01-03T19:44:52Z (6 days ago)
From
Robert Strausbaugh at Eastern Illinois University <rstrausbaugh@eiu.edu>
Via
email
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.