[vsnet-grb-info 13658] GRB 130702A / Fermi394416326 : Nanshan optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14975
SUBJECT: GRB 130702A / Fermi394416326 : Nanshan optical observations
DATE:    13/07/03 19:20:27 GMT
FROM:    Dong Xu at DARK/NBI  <dong.dark at gmail.com>

D. Xu (DARK/NBI), A. Esamdin, L. Ma, X. Zhang (XAO) report:

We observed the field of GRB 130702A / Fermi394416326 (Singer et al.,
GCN 14967; Cheung et al., GCN 14971; Collazzi et al., GCN 14972) using
the 1m telescope located at Mt. Nanshan, Xinjiang Astronomical
Observatory, China. We obtained 3x600s R-band frames, starting from
17:43:25 UT on 2013-07-03 (i.e., 1.735 days after the Fermi trigger).

The optical transient reported in Singer et al. (GCN 14967) is clearly
detected in each of the frames. However, it is slightly overlapped
with its nearby bright galaxy, SDSS J142914.57+154619.3, due to seeing
and technical constraints. The transient has decayed to R~18.9,
calibrated with two bright SDSS stars converted to Johnson R. The
continuous decay makes it likely the optical counterpart of GRB
130702A / Fermi394416326.