GCN Circular 2225
Subject
GRB 030329: Optical limit (contemporaneous imaging)
Date
2003-05-12T03:55:03Z (22 years ago)
From
Ken ichi Torii at RIKEN <torii@crab.riken.go.jp>
Y. Okamoto (NIFTY-Serve Space Forum), K. Ohnishi (Nagano National
College of Technology), and K. Torii (RIKEN) report:
The sky area of the GRB 030329 (Vanderspek, et al., GCN 1997) was
contemporaneously imaged with the Yatsugatake Camera between 2003
March 29 10:00 UT (97 minutes before burst) and 14:00 UT. The
Yatsugatake Camera is an ultra wide field (85 x 70 deg) video camera
(focal length 3.5mm, f/1.4 lens equipped with Sony XC-75) placed at an
altitude of 1000m in Yatsugatake, Japan. Images are output in NTSC
format after 8-s (on-chip) integrations, stored to frame memory (MSJ
SS-10), and recorded to timelapse video tape. The camera has built-in
infrared-cut filter while no additional filter is used.
By now, we have digitized and inspected the data between 10 minutes
before and after the burst and created running mean images of four
consecutive frames. In these images, a neighboring V=5.1 star (41 LMi)
is clearly detected while no transient stellar object brighter than 41
LMi is seen at the position of the optical afterglow (Peterson and
Price, GCN 1985; Torii, GCN 1986). We therefore derive preliminary
upper limit of 5.1 mag for an optical transient associated with this
GRB on continuous 32-s time bins between 2003 March 29 11:27 UT and
11:47 UT. Further analysis is in progress.