GCN Circular 30027
Subject
GRB 210504A: LCO Optical Afterglow Detection
Date
2021-05-16T17:00:44Z (3 years ago)
From
Robert Strausbaugh at U. of the Virgin Islands <robert.strausbaugh@uvi.edu>
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 210504A (Beardmore, et al., GCN 29929) with the LCO 1-m Sinistro instrument at the South African Astronomical Observatory site, on May 5, from 18:49 to 18:56 UT (corresponding to 4.92 to 5.03 hours from the GRB trigger time) with the Bessel R filter.
We performed a series of 3x180s exposures in R. We detect an uncatalogued optical source in the coadded images consistent with the UVOT position (Breeveld, et al., GCN 29933). Using the USNO-B.1 catalog as reference, we calculate the following magnitude:
R=20.29+/-0.18
These magnitudes are not corrected for galactic extinction.
R.S. is funded by NSF AST grant #1831682