GCN Circular 9656
Subject
GRB 090621B: MTM-500 optical observations
Date
2009-07-11T20:19:43Z (15 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
A. Pozanenko (IKI), A. Volnova (SAI MSU), V. Kouprianov, Ya. Naiden, V.
Slesarenko, A. Devyatkin (Pulkovo Observatory), report on behalf of larger
GRB follow-up collaboration:
We observed the field of the Swift GRB 090621B (Curran et al, GCN 9545)
with MTM-500 telescope of Kislovodsk solar station of the Pulkovo
observatory in two series in R-filter between (UT) 2009-06-21 22:31 -
2009-06-22 00:01, i.e. starting ~24 minutes after burst onset. The upper
limit of a stacked image of first 15 frames based on USNO B1.0 stars is
following
T0+ Filter Exp. mag.
(mid, d) s
0.02147 R 15x60 >18.5 (3 sigma)
While we do not detect objects reported in GCN 9547 (Levan et al.) and GCN
9549 (Galeev et al.) in the stacked image above, we may suggest a possible
object near the edge of the refined XRT error box (Beardmore et al., GCN
9550) in coordinates (J2000) RA = 20:53:53.24 Dec = +69:01:45.5. This
possible object appears more intense in the stacked image of the first five
frames, and does not appear in the second epoch of our observations started
on Jun.21 (UT) 23:37. Due to low S/N ratio we cannot confirm the object is
real. We encourage re-analysis of later deep observations to clarify the
nature of the object.
The finding chart can be found at
http://grb.rssi.ru/GRB090621B/grb090621B_MTM.png , where source labeled #5
is the USNO B1.0 star 1590-0172172 (RA(J2000)=20:53:57.28,
Dec(J2000)=+69:01:47.8, R2=19.41)
