GCN Circular 12251
Subject
GRB 110726A: two epochs of SAO RAS optical observations
Date
2011-08-06T07:04:37Z (13 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
A.S.Moskvitin, V.V.Sokolov
report on behalf of the SAO RAS GRB follow-up team:
We observed the field of GRB 110726A (Wolf et al., GCN 12196) with two
optical telescopes of SAO RAS: the 1-m Zeiss-1000 on July, 26/27 in B
and Rc bands and the 6-m BTA + Scorpio on July, 29/30 in Rc band.
We clearly detected an optical transient at the place reported by
Schaefer, Zheng & Flewelling (GCN Circ. 12197, ROTSE-III) and
Siegel & Wolf (GCN Circ. 12199, Swift/UVOT). Results of SAO RAS
observations of OT are presented in the following table.
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date of July, UT filter exp. magnitude telescope
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26.833 -- 27.017 Rc 17 x 300 sec. 22.17 +/- 0.12 Zeiss-1000
26.856 -- 27.022 B 16 x 300 sec. 23.47 +/- 0.17 Zeiss-1000
29.819 -- 29.861 Rc 15 x 180 sec. 23.34 +/- 0.09 BTA
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We use USNO-B.1 1460-0295684 (R. A. = 19:06:51.53, Dec. = +56:04:41.2,
Epoch = 2000.0) with the magnitudes B2 = 20.39, R2 = 18.06
(Gorosabel et al. GCN Circ. 12206) as the reference star.
At the BTA image (ftp://ftp.sao.ru/pub/grb/GRB110726A/GRB110726A_BTA.jpeg)
we detected one more faint object with R = 25.21 +/- 0.30, located 3.5"
North-East from the Swift/UVOT position. According to the Gemini-N redshift
range 1.036 < z < 2.7 reported by Cucchiara Bloom & Cenko (GCN Circ. 12202)
this angle size corresponds to (110 -- 370) +/- 20 kpc.
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