GCN Circular 2392
Subject
GRB030913, candidate afterglow observations
Date
2003-09-20T18:09:43Z (21 years ago)
From
Arne A. Henden at USNO/USRA <aah@nofs.navy.mil>
A. Henden (USRA/USNO) and A. Oksanen (Nyrola Obs.) report
on behalf of the AAVSO International High Energy Network:
We have examined the early-time R-band images from Nyrola
Observatory near the location of the proposed optical
transient of Guziy et al. (GCN 2391). A stack of the
f5.fit and f5b.fit composite images, giving an effective
mid-exposure time of t_0 + 3.5hrs, does not convincingly
show any object at the position shown in the Guziy et al.
finding chart. A jpeg copy of the stack can be found at
http://nyrola.jklsirius.fi/grb/grb030913/f5f5b.jpg
Based on nearby USNO-B stars, we can place a limiting
magnitude of R=19.5 for any object at this location.
Combined with the V=20.9 at t_0 + 4.25day measure of
Guziy et al., this would give an unrealistic decay slope
for a typical GRB. Either this object is unrelated to the
afterglow, or the afterglow increased in brightness after 4hrs.
The AAVSO International High Energy network is grateful for a
generous grant from the Curry Foundation and to NASA for the
financial support for the High Energy Workshops for Amateur
Astronomers.