TITLE:   GCN CIRCULAR
NUMBER:  15392
SUBJECT: GRB 131024B: AAO optical upper limit
DATE:    13/10/28 15:55:03 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of Swift GRB 131024B (Krimm et al., GCN 15371) 
with AS-32 telescope of Abastumani Observatory starting Oct., 25 (UT) 
00:26:12. We obtained several unfiltered images with exposures of 120 s. 
On stacked images within the enhanced XRT circle (Beardmore et al., GCN 
15374) we did not detect any optical counterpart.

The details of the photometry are the following:

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

00:26:12   0.16094     None   46x120   n/d     22.6

The photometry is based 3 SDSS stars, R (gri -> R transformations by
Lupton 2005):

SDSS id             R
J093757.56+441843.7 15.803
J093748.35+441919.6 17.774
J093744.86+441756.7 15.530