TITLE:   GCN CIRCULAR
NUMBER:  2819
SUBJECT: GRB 041016: Optical limits
DATE:    04/10/17 08:14:58 GMT
FROM:    Ken ichi Torii at RIKEN  <torii@crab.riken.go.jp>

K. Torii and Yuuichi Fukazawa (Osaka University) report:

 We have further analyzed the data reported in GCN #2813 and derived
the following limits on the optical afterglow of GRB 041016 (HETE
Trigger #3578). We made two pointings
and obtained 12 x 300-s frames for each pointing. The 12 frames from
each pointing was stacked to yield a single frame and compared with
the USNO-A2.0 (R) catalog. We found no new source brighter than the
limiting magnitude of each frame as given below.

 The first pointing (07:14 UT - 08:26 UT) 
was 24x24 arcmin field centered at 
(RA, Dec.) = (01 44 53, -04 17 12) (J2000). The limiting magnitude
of the stacked frame was 18.4.

 The second pointing (08:36 UT - 09:48 UT)
was 24x24 arcmin field centered at 
(RA, Dec.) = (01 44 48, -04 24 21) (J2000). 
The limiting magnitude of the stacked frame was 18.7.

 Starting at 11:54 UT on 2004 October 16, a part of the GRB 041016
error region was also observed at Osaka University with the 14-inch
telescope and unfiltered CCD. We stacked the first 60 frames of 60-s
exposure and compared it with the USNO-A2.0 (R) catalog. No new source
brighter than 18.2 mag was found in the 25x25 arcmin field centered at
(RA, Dec.) = (01 44 39, -04 12 13) (J2000).

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