[vsnet-grb-info 18698] GRB 161108A: NOT candidate afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20146
SUBJECT: GRB 161108A: NOT candidate afterglow
DATE:    16/11/08 06:08:47 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

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.