GCN Circular 32289

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

Following the Fermi/LAT detection and localisation of GRB 220627A (Di Lalla
et al., GCN 32283
Not found
 
 
), also proposed to be a lensed or ultra-long GRB
candidate by Fermi/GBM (Roberts et al., GCN 32288
Not found
 
 
), the 0.6 m wide-field
MeerLICHT optical telescope obtained 2x300s observations in the q-band of
two fields encompassing the LAT error box starting at 17:12:15 UT on 2022
June 28, approximately 1.17 days after the GBM trigger. We note that these
two fields were not observed during observations of the Fermi/GBM error box
from the previous night (Groot et al., GCN 32281
Not found
 
 
). We also note that the
two transient candidates from those observations are not consistent with
the Fermi/LAT errorbox, therefore we exclude their association with GRB
220627A.

Within the error box of the uncatalogued X-ray Source 3 discovered by
Swift/XRT through ToO observations (Evans, GCN 32284
Not found
 
 
), we detect a new
transient candidate at the following coordinates:

RA (J2000) = 13:25:28.49 (201.36872d)
Dec (J2000) = -32:25:33.31 (-32.42592d)

calibrated against Gaia DR2, with a positional uncertainty of 0.1" in each
coordinate. The same object is detected in a further 2x300s observations ~1
hour later. The source is detected with an AB magnitude of

q = 21.25 +/- 0.09

in the first exposure. We detect no source at the transient location in an
archival image of the same field down to a 3-sigma limiting magnitude of q
> 21.71. We suggest this may be the afterglow of GRB 220627A. Further
follow-up is encouraged.

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.