TITLE:   GCN CIRCULAR
NUMBER:  31974
SUBJECT: GRB 220430A: MeerLICHT optical upper limits
DATE:    22/04/30 19:04:51 GMT
FROM:    Paul Groot at Radboud University Nijmegen  <p.groot@astro.ru.nl>

P.J. Groot (Radboud/UCT/SAAO), S.de Wet (UCT), D.B. Malesani
(Radboud, DAWN/NBI), A.J. Levan (Radboud), P.M. Vreeswijk (Radboud),
report on behalf of the MeerLICHT consortium:

GRB220430A (Ambrosi et al., GCN 31972) triggered automatic observations
with the 0.6m wide-field MeerLICHT telescope, located at Sutherland,
South Africa. Observations started at 2022-04-30, 17:10:19 UT in a
series of 60s integrations in an alternating sequence of the
u,g,q,r,i,z bands. Observations were stopped after 2022-04-30,
17:27:48 UT due to the visibility of the source location. 

A preliminary analysis of the u, q and i-band images shows no new
optical transient in these bands within the Swift-BAT error circle,
including the position of the new X-ray source detected in the Swift-XRT
observations. 

Five-sigma limiting magnitudes for an optical transient located at the
Swift-XRT position are: 
u > 19.0 at 17:11:46 UT, 
q > 20.4 at 17:13:14 UT, 
i > 18.6 at 17:20:32 UT. 

Further analysis is ongoing

MeerLICHT is built and run by a consortium consisting of Radboud
University, the University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester
and the University of Amsterdam.