GCN Circular 32572
Subject
GRB 220921A: MeerLICHT afterglow observations
Date
2022-09-22T10:02:05Z (2 years ago)
From
Simon de Wet at UCT <dwtsim002@myuct.ac.za>
S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO) and D.A.H Buckley (SAAO)
report on behalf of the MeerLICHT consortium:
Following the detection of GRB 220921A by Fermi/LAT (Pillera et al., GCN
32568), the 0.6m wide-field MeerLICHT telescope, located at Sutherland,
South Africa, obtained a repeated series of 60s exposures of a field
encompassing the entire LAT error box in the q,u,g,r,i,z bands following
the sequence quqgqrqiqz. Observations started at 01:29:34 UT on September
22 and continued for approximately two hours.
We detect the previously reported afterglow to GRB 220921A at a position
consistent with the MASTER and Swift/XRT positions (Lipunov et al., GCN
32570; Kingler et al., GCN 32571) with the following AB magnitudes at a
mid-time of September 22 01:46:00 UT, 0.61 days after the LAT trigger time:
u = 19.28 +/- 0.14
g = 18.64 +/- 0.03
q = 18.47 +/- 0.02
r = 18.43 +/- 0.04
i = 18.25 +/- 0.05
z = 18.24 +/- 0.11
We note that the source is exhibiting fading behaviour with respect to the
previously reported MASTER brightness (Lipunov et al., GCN 32570).
MeerLICHT is built and run by a consortium consisting of Radboud
University, University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester and the
University of Amsterdam.