D. Malesani (DARK/NBI and DTU Space), A. de Ugarte Postigo (IAA-CSIC and
DARK/NBI), A. Somero (UTU), E. Gafton (NOT, SU, OKC), S. Damsted (Univ.
Helsinki), G. Erfanianfar (MPE), A. Finoguenov (Univ. Helsinki), C.
Gibson (Univ. Helsinki), F. Kiefer (MPE), C. Kirkpatrick (Univ.
Helsinki), M. Lumme (Univ. Helsinki), V. Oja (Univ. Helsinki), J.
Rantakyla (Univ. Helsinki), I. Salmenpera (Univ. Helsinki), and M.
Seppala (Univ. Helsinki), report on behalf of a larger collaboration:
We observed the field of GRB 161108A (Beardmore et al., GCN 20145) with
the Nordic Optical Telescope (NOT) equipped with the AlFOSC imager and
spectrograph. Observations started on Nov 8.2132 UT (94.4 min after the
GRB trigger) and were carried out in the r and z filters.
Within the currently available XRT position (Beardmore et al., GCN
20145), we detect a single object, at coordinates (J2000):
RA = 12:03:09.11
Dec = +24:52:04.9
This source has a magnitude r = 20.82 +- 0.05 AB, calibrated against
nearby SDSS stars. The same object is visible in the SDSS archival
images, at a significantly fainter magnitude r = 22.69 +- 0.20. It is
classified as a galaxy with a photometric redshift of 0.50 +- 0.12. The
most likely interpretation is that the object seen in the NOT images is
the superposition of afterglow and host galaxy, so we consider the
association with GRB 161108A secure.