GRB 241213A: LCOGT Optical Upper Limits

We observed the Swift GRB 241213A field (Gupta et al., GCN 38547) with the LCOGT 1-meter Sinistro instrument at the McDonald Observatory USA site, on December 13, from 06:49 to 07:19 UT (corresponding to 4.50 to 5.00 hours after the GRB trigger time) with the sdss r and i filters. We performed a series of 3x300s exposures in i-band and 2x300s in r-band. We do not detect a source within the Swift XRT enhanced error region (Osborne et al., GCN 38552) in either band, consistent with other optical upper limits (Lipunov et al., GCN 38548; Spiridonova et al., GCN 38550; Brivio et al., GCN 38553). The following 5-sigma upper limits are calculated using the PanSTARRS catalog as reference: r > 21.2 i > 21.5 These magnitudes are not corrected for galactic extinction.