GCN Circular 16221
Subject
GRB 140502A: ISON-NM early optical limit
Date
2014-05-07T20:16:19Z (10 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
L. Elenin (KIAM), A. Volnova (IKI), I. Molotov (KIAM), A. Pozanenko
(IKI) report on behalf of larger GRB follow-up collaboration:
We observed of the field of Swift GRB GRB 140502A with 0.4-m
telescope of ISON-NM observatory starting on May, 02 (UT) 08:31:32,
i.e. 72 s after BAT trigger (Swenson et al., GCN 16202). We took series
of unfiltered images of 30 s - 60 s exposures. A bright star (USNO-B1.0
1389-0392112) already mentioned (Oates et al., GCN 16210) lies within
enhanced XRT error circle (Goad et al., GCN 16206). We investigate
variability of a possible OT in presence in near vicinity of the
bright star. The upper limit of possible variation of the OT is 16.6m
within any of 60 s interval of our observations between (UT) 08:31:32
and 09:24:25 which can be considered as an upper limit on the OT
associated with GRB 140502A.
Formal photometry and limiting magnitude of point-like source in the
observed field is following
UT start t-T0 Exp. Filter OT UL(3 sigma)
(mid.,days) (s)
08:31:32 0.00383 10*30 None n/d 18.8
and based on nearby USNO-B1.0 stars, R2 magnitudes.