GCN Circular 12062

A. Volnova (SAI MSU),   E. Klunko (ISTP),  A. Pozanenko (IKI) on behalf of 
larger GRB follow up collaboration report:

We observed the optical afterglow  of the Swift   GRB 110530A (D'Avanzo et 
al, GCN 12046
Not found
 
 
) with AZT-33IK telescope of Sayan observatory (Mondy) on May, 
30 between (UT) 16:06:01 - 19:14:06 (i.e. t0+0.0243 d -- t0+0.1549 days 
after burst trigger). We took several series of 60 s exposures in R. Optical 
afterglow is detected in single images in the beginning of the observations 
while in the end we stacked images in 180 - 300 s combined exposures. The 
photometry is based on the USNO-B1.0 1519-0265568 star (RA=18 48 15.86, 
Dec=+61 56 15.0) assuming R=16.08.   In particular, the photometry

UT (mid time), Exposure,   Filter,     OT
18:04               5x60          R           20.25 +/- 0.06
18:54               5x60          R           20.58 +/- 0.07

coincide with the photometry reported earlier (Andreev et al., GCN 12052
Not found
 
 
).

Preliminary light curve can be found at

http://grb.rssi.ru/GRB110530A/GRB110530A_AZT33IK_lc.png

One can note a non-monotonous light curve decay with possible rebrightening 
at  0.03 d and 0.53 d and general power law decay index of about 0.9.