[vsnet-grb-info 14970] GRB 140423A: AAO optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16264
SUBJECT: GRB 140423A: AAO optical upper limits
DATE:    14/05/14 14:27:00 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

A. Volnova (IKI), R. Inasaridze (AAO), O. Kvaratskhelia (AAO), V. 
Ayvazian (AAO), Yu. Krugly (IA KhNU), I. Molotov (KIAM), A. Pozanenko 
(IKI) report on behalf of larger GRB follow-up collaboration:

We observed the optical afterglow (Elenin et al., GCN 16143; Kaur et 
al., GCN 16144; Ferrante et al., GCN 16145; Chester et al., GCN 16147; 
Maehara et al., GCN 16151) of the Swift GRB 140423A (Sonbas et al., GCN 
16142) with AS-32 (0.7m) telescope of Abastumani Observatory on Apr. 24 
at (UT) 00:29-01:16 and Apr. 24 (UT) 17:46-19:16. We obtained several 
unfiltered   frames with exposures of 120 s. Within the enhanced XRT 
circle (Beardmore et al., GCN 16155) in the stacked images from both 
epochs we do not detect the afterglow.

The details of the photometry are the following:

UT start   t-T0         Filter   Exp.    Uplim
           (mid, days)   (s)              (3 sigma)
00:29:23  0.68139       None    16*120   20.3


The photometry is based on SDSS stars, R mag (R mag obtained using ugriz
transformations in BVRI (Lupton, 2005):

SDSS id                R_Lupton
J130858.37+494547.9   15.418 ± 0.018
J130914.51+494636.5   18.661 ± 0.019