TITLE: GCN CIRCULAR NUMBER: 32596 SUBJECT: GRB 220921A: LCOGT Optical Observations DATE: 22/09/27 18:10:04 GMT FROM: Robert Strausbaugh at University of Minnesota rstrausb@umn.edu
R. Strausbaugh (University of Minnesota), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:
We observed the Fermi-LAT detection GRB 220921A (Pillera et al., GCN 32568) field with the Las Cumbres Observatory Global Telescope Network (LCOGT) 1-meter Sinistro instrument at the South African Astronomical Observatory site, on September 22, from 00:18 to 00:45 (corresponding to 13.22 to 14.57 hours from the GRB trigger time) with the Bessel I and R filters.
We performed a series of 3x300s exposures in R and I bands. We detect the MASTER optical afterglow candidate (Lipunov et al., GCN 32570), in both bands, consistent with other optical detections (de Wet et al., GCN 32572; Watson et al., GCN 32576).
The following magnitudes are calculated using the USNO-B1 catalog as reference:
R= 18.02 +/- 0.27 I= 17.78 +/- 0.36
We also observed the afterglow of GRB 220921A with the LCOGT 1-meter Sinistro instrument at the Cerro Tololo Interamerican Observatory, Chile site, on September 23, from 04:50 to 05:18 (corresponding to 41.75 to 42.22 hours from the GRB trigger time) with the Bessel I and R filters.
We performed a series of 3x300s exposures in R and I bands. We detect the MASTER optical afterglow candidate (Lipunov et al., GCN 32570) in both bands.
The following magnitudes are calculated using the USNO-B1 catalog as reference:
R= 19.26 +/- 0.34 I= 19.03 +/- 0.39
These magnitudes are not corrected for galactic extinction. Further observations are planned.