TITLE:   GCN CIRCULAR
NUMBER:  19136
SUBJECT: GRB 160303A: Optical observations from the NOT
DATE:    16/03/03 23:39:37 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D. Malesani (DARK/NBI),
N.R. Tanvir (U. Leicester), Z. Cano (U. Iceland), M. Messa (Stockholm 
Univ., Oskar Klein Centre), E. Gafton (NOT, Stockholm Univ. and Oskar 
Klein Centre) and I. R. Losada (Nordita and Stockholm Univ.) report on 
behalf of a larger collaboration:

We observed the field of the possibly short GRB 160303A (Beardmore et al., 
GCN 19126) with MOSCA at the 2.5m Nordic Optical Telescope (La Palma, 
Spain). Observations started at 21:32 UT (10.63 hr after the burst). In an 
8x300s r-band exposure we detect a source consistent with the counterpart 
candidate identified by RATIR (Butler et al. GCN 19131), and also seen by 
UVOT (Emery et al. GCN 19134).

Comparing with SDSS field stars we obtain a photometric value of 
r=23.43+/-0.15 (AB). This would imply only a modest (if any) fading 
compared to the RATIR observation. This may be indicative of a significant 
contribution from an underlying host galaxy.

We do note that the coordinates that we measure are slightly offset from 
those given in the RATIR GCN, being our object marginally outside the 
refined XRT error circle(Evans et al., GCN 19132,  
http://www.swift.ac.uk/xrt_positions/00677495/ <http://www.swift.ac.uk/xrt_positions/00677495/>), at the following coordinates 
(J2000, +/- 0.3"):

RA = 11:14:48.06
Dec = +22:44:32.2