GCN Circular 14182
Subject
GRB 130131A: optical observation in Mondy observatory
Date
2013-02-06T20:27:48Z (11 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Volnova (SAI MSU/IKI), I. Korobtsev (ISTP), E. Klunko (ISTP), A.
Pozanenko (IKI) report on behalf of larger GRB follow-up collaboration:
We observed the field of the Swift GRB 130131A (Grupe et al., GCN 14156)
with AZT-33IK telescope of Sayan observatory (Mondy). We took several
images in R-filter of 60 s exposure on Jan. 31, between (UT)
14:12:36-15:36:53 under favorable weather conditions with a FWHM of
about 2.5". In the stacked images we detected a source which is
coincident with the source reported by Tanvir et al. (GCN 14157). The
photometry based on SDSS DR8 is the following:
t_start, T0+ (mid), filter, exp., OT+/-err UL (3 sigma)
(UT) d s
14:12:36 0.01640 R 10x60 22.5 +/-0.35 22.4
14:12:36 0.04053 R 79x60 23.4 +/-0.25 23.5
Taken coincidence with source detected in IR (Tanvir et al. GCN 14157)
and fading nature of the source we suggest that we detect OT of GRB
130131A. The detection in R filter confirms that the GRB 130131A is not
an extreme redshift event (Tanvir et al. GCN 14175). Also we compared
fluxes in X-ray and optic at ~0.016 days after trigger and found that
the GRB 130131A can be considered as optically dark burst following the
both criteria (Jakobsson et al., 2004; van der Horst et al., 2009).
The stars used for photometry and assumed R mags:
J112419.01+480710.6 11:24:19.01 +48:07:10.7 R = 18.93
J112414.86+480528.8 11:24:14.86 +48:05:28.9 R = 18.77
J112419.60+480357.4 11:24:19.61 +48:03:57.5 R = 20.32
The finding chart of the stacked image can be found in
http://grb.rssi.ru/GRB130131A/GRB130131A_130131_AZT33IK.png
