TITLE: GCN CIRCULAR NUMBER: 42043 SUBJECT: GRB 251001B: LCOGT Optical Observations DATE: 25/10/01 15:44:16 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 251001B field (Beardmore et al., GCN 42039) with the LCOGT 1-meter Sinistro instrument at the Siding Spring Observatory, Australia site, on October 1, from 14:51 to 15:23 UT (corresponding to 0.57 to 1.10 hours after the GRB trigger time) with the SDSS i and r filters. We performed a series of 3x300s exposures in i-band and r-band. We detect an uncatalogued source consistent with other optical counterpart observations (Gompertz et al., GCN 42040; An et al., GCN 42041) in both bands. We note that our r-band measurement implies a rapidly fading source. The following magnitudes are calculated using the PanSTARRS catalog as reference: r = 20.26 +/- 0.04 i = 19.81 +/- 0.03 These magnitudes are not corrected for galactic extinction. View this GCN Circular online at https://gcn.nasa.gov/circulars/42043. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...