[vsnet-grb-info 17098] GRB 151006A: Mondy optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18416
SUBJECT: GRB 151006A: Mondy optical upper limit
DATE:    15/10/11 10:03:30 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

E. Mazaeva (IKI), E. Klunko (ISTP), A. Volnova (IKI), I. Korobtsev 
(ISTP),  A. Pozanenko (IKI) report on behalf of larger GRB follow-up 
collaboration:

We observed the field of Swift GRB 151006A (Kocevski et al., GCN 18398) 
with AZT-33IK telescope of Sayan observatory (Mondy) starting on Oct. 18 
(UT) 16:50:47. We obtained several images in R-filter of 120 s exposure. 
    Within XRT error circle (Goad et al., GCN 18403)  we do not detect 
any optical source. Upper limit is following

Date       UT start   t-T0     Filter   Exp.    UL (3 sigma)
                       (mid, days)       (s)

2015-10-06 16:50:47   0.31306  R        35*120  22.4

Photometry is based on USNO-B1.0 stars:
USNO-B1.0_id R2
1604-0085829 18.23
1604-0085812 16.90