GCN Circular 3455
Subject
GRB050509b: optical observations
Date
2005-05-22T21:31:42Z (20 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.
This message may be cited.