GCN Circular 22841
Subject
GRB 180613A: LCO Afterglow detection
Date
2018-06-25T11:26:35Z (6 years ago)
From
Antonino Cucchiara at UVI <antonino.cucchiara@uvi.edu>
A. Cucchiara, D. Morris (U. Virgin Islands), C. Guidorzi,
R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell
(U. Bath), report report on behalf of a larger collaboration:
"On June 13.84 UT (T_0 +4.5 hours) we began observing the
center of the field of GRB 180613A (Tohuvavohu et al. GCN 22769,
Beardmore et al. GCN 22773) using the Las Cumbres Observatory
1m telescope located South Africa Astronomical Observatory.
We performed a series of 5x120s observations in SDSS-i' and
SDSS-r' band for a total of 20 minutes on sky.
In the full median stacked i'-band images we clearly identified the
NIR counterpart reported by Thoene et al. (GCN #2275, #22820).
This object is also marginally detected in our r' band stack.
We estimate the following brightness for the optical counterpart:
i' = 19.3 +- 0.6
We caution the usage of this measurement due to the high sky
background near the GRB location caused by the presence of the
nearby by a nearby 5.6 mag star (Schady et al. GCN #22777).
This magnitude is calibrated against nearby UCAC4 sources,
and is not corrected for Galactic extinction."