GCN Circular 3455
Subject
GRB050509b: optical observations
Event
Date
2005-05-22T21:31:42Z (21 years ago)
From
Vasilij Rumjantsev at CrAO <rum@crao.crimea.ua>
V.Rumyantsev (CrAO), V.Biryukov (SAI, MSU), B. Kahharov, M. Ibrahimov, D.
Sharapov (MAO), A.Pozanenko (IKI) on behalf of larger GRB follow up
collaboration report:
We observed the refined XRT error circle (Rol et al, GCN3395) of GRB050509b
(Hurkett et al, GCN3381) with 2.6m F/3.85 Shajn telescope (ZTSh, CrAO)
equipped with FLI IMG1001E CCD camera and 1.5m telescope (Maidanak
Astronomical Observatory) on May 9 and 10. Maidanak observation took place
on May 9 (16:48 - 18:31 UT) and May 10 (16:15 - 18:20 UT) in R-band with
total exposure of 3600 sec in each date. ZTsh observation starts on May 9,
18:26 (UT) with total exposure of 3360 sec in R- and 1680 sec in I-band. The
source S1 (S. Bradley Cenko et al, GCN3391, 3401) is visible in R and I.
USNO B1.0 catalog is used for calibration and photometry of S1 source in R
and I band:
UT Telescope Exp. Band magnitude
May 9 16:48-18:31 1.5m 3600 R 22.88 +/-0.13
May 9 18:51-20:02 2.6m 1680 I 22.72 +/-0.23
May 9 18:26-21:16 2.6m 3360 R 22.79 +/-0.08
May 10 16:15-18:20 1.5m 3600 R 22.93 +/-0.18
May 9+10 1.5m 7200 R 22.92 +/-0.07
(Magnitude of the S1 may be biased due to highlighting of bright galaxy.)
Stacked images and stars used for calibration can be found in
http://grb.rssi.ru/GRB050509b.
While no variable optical source was found till now (G. Kosugi et al,
GCN3422) the data obtained may be useful for long term monitoring of S1.
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