[vsnet-grb-info 20677] GRB 180613A: Possible IR afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22775
SUBJECT: GRB 180613A: Possible IR afterglow
DATE:    18/06/14 01:45:46 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

C. C. Thoene (HETH/IAA-CSIC), N. Tanvir (Univ. of Leicester), A. de Ugarte
Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, L. Izzo (both
HETH/IAA-CSIC), G. Pugliese (API/U. Amsterdam), P. Schady (MPE) and D. Xu
(NAO/CAS) report on behalf of the Stargate consortium:


We observed the field of GRB 180613A (GCN 22769, Tohuvavohu et al.) with
HAWKI at the VLT (ESO, Paranal, Chile) starting on June 13, 2018, at 22:51
UT (7.25 days after the burst). Imaging observations were obtained in J, H
and Ks filters with exposure times of 11-12 min under thin clouds but
excellent seeing conditions (around 0.4 arcsec) and preliminary reductions
provided by the observatory.

The object reported in GCN 22772 (Kann & Izzo) is clearly detected and
likely a foreground star. Inside the refined XRT error circle (GCN 22771,
Evans) we detect a faint source in all three bands at the coordinates
(errors +/-0.5 arcsec):

RA 14:06:04.89
DEC -43:04:19.6

The source seems to be slightly extended to the NW and a point-like source
at the SW end of it. This could possibly be the underlying host +
afterglow. Further observations are needed to determine a possible fading
of the source. Preliminary photometry gives J = 22.86 +/- 0.25 mag using
aperture photometry centered on the point-like part of the source and
compared to field stars from the 2MASS catalogue.

We acknowledge the excellent support from ESO staff, in particular Frédéric
Vogt, Ivan Aranda and Stephane Brillant and enjoyed the great new option to
chat on Skype with the telescope during the observations.