TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1936
SUBJECT: GRB 030227: Optical limit at RIKEN
DATE:    03/03/10 11:14:26 GMT
FROM:    Ken ichi Torii at RIKEN  <torii@crab.riken.go.jp>

K. Torii (RIKEN), T. Kato (Kyoto U.), and H. Yamaoka (Kyushu U.)
report:

 In response to the IBAS alert message (INTEGRAL Trigger #214), the
entire error region of GRB 030227 (Gotz, et al., GCN 1895 and 1896)
was observed by the automated system at RIKEN (0.25-m f/6.8 reflector
equipped with unfiltered CCD AP6E). The observation started at 2003
Feb. 27 09:31:39 UT (49 minutes after the burst). After 73 frames of
40-s integration were acquired, 60-s integration was repeated.

 We have applied PSF photometry to these data. The optical transient
(Casto-Tirado, et al., GCN 1904; Soderberg, et al., GCN 1907; Berger,
et al., GCN 1910) is not significantly detected.

 By using Henden's sequence (GCN 1917), we preliminarily estimate a
star at (04:57:16.351, +20:27:00.66) (USNO-A2.0 position) as Rc = 11.7
and derive 3-sigma upper limits for the optical transient as follows.

-------------------------------------------------------
Rc Mag. / Mean Epoch (UT) / (Start - End) / Integration
-------------------------------------------------------
>20.3  09:41:03 (09:31:39 - 09:50:26) 40-s x 24 frames
>20.4  10:08:45 (09:50:31 - 10:26:58) 40-s x 49 frames
-------------------------------------------------------