[vsnet-grb-info 13089] GRB 130420B: Weihai optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14426
SUBJECT: GRB 130420B: Weihai optical upper limit
DATE:    13/04/20 22:06:40 GMT
FROM:    Dong Xu at DARK/NBI  <dong.dark at gmail.com>

Dong Xu (DARK/NBI), Chen Cao, Shaoming Hu, Dayong Ren (SDU) report:

We observed the field of GRB 130420B (Oates et al., GCN 14411) using
the 1m telescope located in Weihai, Shandong Province, China. We
obtained 12x300s I-band frames with a mean time of 2.973 hr after the
BAT trigger.

No optical source is detected within the enhanced XRT error circle
(Page et al., GCN 14421) in the stacked image, down to a limiting
magnitude of I>21.2 mag.