[vsnet-grb-info 14827] GRB 140419A: Mondy optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16141
SUBJECT: GRB 140419A: Mondy optical observations
DATE:    14/04/22 14:44:54 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

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

We observed the field of the Swift GRB 140419A (Marshall et al., GCN
16118) with AZT-33IK telescope of Sayan observatory (Mondy) on Apr. 
19-21. We took several images in R-filter of 60 s exposure. On stacked 
images we clearly detected the optical afterglow (Zheng et al., GCN 
16119; Guver et al., GCN 16120; Butler et al., GCN 16121; Kuin et al.,
GCN 16123; Hentunen et al., GCN 16126) except the combined image of
Apr. 19 due to unfavorable weather conditions. Our photometry is 
consistent with the decaying law derived from RATIR observations 
(Littlejohns et al., GCNs 16139, 16136).

The details of the photometry are the following:

date        UT start   t-T0     Filter  Exp.  OT             Uplim
                       (mid, days)       (s)                 3sigma

2014-04-19 16:26:35   0.52030   R      10*60  n/d             19.3
2014-04-20 14:49:15   1.47495   R      83*60  21.12 +/- 0.10  21.6
2014-04-21 14:58:36   2.49015   R     107*60  21.60 +/- 0.15  22.2

The photometry is based on nearby SDSS star, R (gri -> R transformations 
by Lupton 2005):

SDSS id              R
J082752.69+461357.4  17.381 +/- 0.018