Skip to main content
New Swift-BAT/GUANO and IceCube Notice Types Available! See news and announcements

GCN Circular 32281

GRB 220627A: MeerLICHT detection of two afterglow candidates
2022-06-28T02:12:29Z (a year ago)
Paul Groot at Radboud University Nijmegen <>
P.J. Groot (Radboud/UCT/SAAO), S. de Wet (UCT/SAAO), P.M. Vreeswijk
(Radboud) report on behalf of the MeerLICHT consortium:

Following the detection of GRB220627A by Fermi (Fermi GBM team, GCN
32278) the MeerLICHT 0.6m wide-field optical telescope, located at
SAAO Sutherland, South Africa, started scanning the error box at
2022-06-27 21:43 UT (T0+23 minutes and 3 minutes after the alert was
received). Observations were obtained in the q-band (440-720nm), using
52 tiles (146 square degrees) to cover a 71% cumulative
probabilty. Before the observability limit of HA=+4.5 hr was reached
32.4 square degrees were covered at least twice, covering a cumulative
probability of 7.5% of the Fermi error box.

Automatic data processing using BlackBOX/ZOGY resulted in 7 new
transients that were observed at least twice and were detected with a
significance >12 in the difference images. Five of these candidates
can be associated to known asteroids. 

The remaining two candidates are uncataloged and are both detected
three times: 

Candidate 1 is MLTJ143615.50-360417.3,
at RA,Dec (ICRS) 14:36:15.50, -36:04:17.3 (219.06459,-36.07149),
first detected at q_AB = 18.13+/-0.03 on 2022-06-27 22:50:22/05 (MJD
59757.95164). Last non-detection was on MJD 58971.02.19 at q_AB > 20.35
(for a transient source).  

Candidate 2 is MLTJ143614.90-373629.0,
at RA,Dec (ICRS) 14:36:14.90. -37:36:29.0 (219.06217,-37.60809),
first detected at q_AB = 19.62+/-0.10, on 2022-06-27 22:53:20.54 (MJD
59757.95371). Last non-detection was on MJD 59737.8835 at q_AB > 20.82

Candidate 1 shows the presence of an underlying object in the MeerLICHT
reference image at q_AB = 20.72, possibly a host galaxy. 
Candidate 2 shows no underlying source in the MeerLICHT reference image
with a limiting magnitude of q_AB > 20.28. 

During the three MeerLICHT observations Candidate 1 evolved to q_AB =
18.21 +/-0.02 at 2022-06-27 23:16:51 (MJD 59757.97004). Candidate 2
brightened to q_AB = 19.43 +/- 0.10 at 2022-06-27 23:18:14 (MJD

Follow-up observations of both candidates are 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.
Looking for U.S. government information and services? Visit