TITLE: GCN CIRCULAR NUMBER: 27759 SUBJECT: GRB 200519A: LCO Optical Afterglow Detection DATE: 20/05/19 17:04:42 GMT FROM: Robert Strausbaugh at U. of the Virgin Islands R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (U. of the Virgin Islands/College of Marin) report on behalf of a larger collaboration: We observed Swift GRB 200519A (Sbarufatti et al., GCN 27756) with the LCO 1-m Sinistro instrument at the Siding Spring Observatory Australia site, on May 9, from 12:39 to 13:02 UT (corresponding to 1.05 to 1.38 hours from the GRB trigger time) with the Bessel R and I filters. We performed a series of 5x120s exposures in R and I. We detect an optical source in stacked images at the UVOT afterglow candidate position position. Using the USNO-B.1 catalog as reference, we calculate the following magnitudes: R = 17.07 +/- 0.02 I = 16.69 +/- 0.02 These magnitudes are not corrected for galactic extinction. R.S. is funded by NSF AST grant #1831682