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GCN Circular 15485

GRB 131108A: ISON Blagoveshensk upper limit
2013-11-14T06:21:44Z (11 years ago)
Alina Volnova at SAI MSU <>
A. Volnova (IKI), D. Varda (ISON), E. Sinyakov (ISON), I. Molotov
(KIAM), A. Pozanenko (IKI) report on behalf of larger GRB follow-up

We observed the field of GRB 131108A (Racusin et al., GCN 15464,
Hurley et al., GCN 15466) with ORI-25 telescope of ISON-Blagoveshensk
observatory starting Nov., 9 (UT) 16:40:45. We took several unfiltered
images with exposures of 30 seconds. In the combined images in the
enhanced XRT circle (Stroth & Kennea, GCN 15474) we do not detect the
OT reported by Gorosabel et al. (GCN 15469).

The details of the photometry are the following:

UT start      t-T0     Filter    Exp.    OT         UL (3sigma)
               (mid, days)           (s)
16:40:45   0.85072  None  95x30  n/d   17.1

The photometry is based on a nearby bright SDSS star, R (gri -> R
transformations by Lupton 2005):

SDSS id                      R
J102613.43+094109.5  13.318 +/- 0.013
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