GCN Circular 32032
Subject
GRB 220427A: MeerLICHT afterglow observations
Date
2022-05-13T08:01:30Z (2 years ago)
From
Simon de Wet at UCT <dwtsim002@myuct.ac.za>
S. de Wet (UCT), D.B. Malesani (Radboud), P.M. Vreeswijk (Radboud)
and P.J. Groot (Radboud/UCT/SAAO) report on behalf of the MeerLICHT
consortium:
Following the detection of GRB 220427A by Swift and its X-ray counterpart
(D'Ai et al., GCN 31960), the 0.6m MeerLICHT telescope, located at
Sutherland, South Africa obtained a repeating series of 60 s images in the
q,u,q,g,q,r,q,i,q,z bands. Observations began at 2022-04-27, 23:41:48 UT,
2 hours 41 minutes after the Swift detection, and continued for a further
4.5 hours. The median seeing was 2" under clear skies.
No source is detected at the optical transient position (D'Ai et al., GCN
31960)
in any individual 60 s exposure, hence we co-added all the images in each
filter and performed forced photometry at the transient position. The
afterglow
is detected with a SNR of at least 7 in the g,r,i,z and q bands. We
report the following upper limit and AB magnitudes, at 3 hours 50 minutes
post-trigger:
u > 21.83
g = 21.26 +/- 0.11
q = 21.14 +/- 0.09
r = 20.88 +/- 0.12
i = 20.49 +/- 0.13
z = 19.59 +/- 0.15
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.