TITLE:   GCN CIRCULAR
NUMBER:  14307
SUBJECT: GRB 130313A: TNG optical observations
DATE:    13/03/14 15:45:14 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo@brera.inaf.it>

P. D'Avanzo, S. Covino, A. Melandri (INAF/OAB), C. P. Padilla Torres, G.
Andreuzzi (INAF/TNG) report on behalf of the CIBO collaboration:

We observed the field of GRB 130313A (Gompertz et al., GCN 14293) with the
TNG telescope located in the Canary Islands. A total 1800 s exposure in
the SDSS r filter was acquired, with mean time 2013 Mar 14.2314 UT (13.4
hours after the GRB). Sky conditions were good and the seeing was 0.9".

No clear optical afterglow is detected inside the refined XRT error circle
(Osborne et al. GCN 14300; Gompertz et al., GCN 14305) down to a limiting
magnitude r~25 mag (3sigma c.l.; calibrated against nearby SDSS stars). In
particular, we do not detect the 3 optical sources reported by de Ugarte
Postigo et al. (GCN 14302).