[vsnet-grb-info 9723] GRB 100901A: optical observation at Mt.Terskol
GCN Circulars
gcncirc at capella2.gsfc.nasa.gov
Fri Sep 3 15:56:26 JST 2010
TITLE: GCN CIRCULAR
NUMBER: 11191
SUBJECT: GRB 100901A: optical observation at Mt.Terskol
DATE: 10/09/03 06:56:22 GMT
FROM: Alexei Pozanenko at IKI, Moscow <apozanen at iki.rssi.ru>
M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy) and
A.Pozanenko (IKI) on behalf of larger GRB follow up collaboration report:
We are continuing observations of the Swift GRB 100901A (Immler et al., GCN
11159) with the Z-600 telescope of Mt.Terskol observatory in R-filter
(Andreev et al., GCN 11166). In a combined image at mid time Sep. 03 (UT)
00:36 we detect afterglow (Immler et al., GCN 11159; Guidorzi et al., GCN
11160; Ivanov et al., GCN 11161; Klunko et al., GCN 11162).
In comparison with our previous photometry (Andreev et al., GCNs 11166,
11168) below we used several reference stars of SDSS DR7 and Lupton
transformation ugriz -> BVRI:
T0+ Filter, Exposure, OT
(d) (s)
1.4599 R 10x120 19.22 +/- 0.05
The photometry above is consistent with steady decay based on early
photometry (Kann et al, GRB 11187). We note however the systematic faintness
of about ~0.25m in SDSS DR7 in comparison with USNO-B1.0 R2 which can
explain possible contradiction of MITSUME observation calibrated against
SDSS (Kuroda et al, GCN 11189) and photometry reported in Yoshida et al
(GCN 11190). Detailed calibration of the field stars is necessary.
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