[vsnet-grb-info 7927] GRB 090531B, RIMOTS optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9470
SUBJECT: GRB 090531B, RIMOTS optical upper limits
DATE:    09/06/01 13:32:06 GMT
FROM:    Eri Sonoda at U of Miyazaki/Japan  <sonoda at astro.miyazaki-u.ac.jp>

E. Sonoda, K. Noda, N. Ohmori, K. Kono, H. Hayasi,
A. Daikyuji, Y. Nisioka, M. Yamauchi
(University of Miyazaki)

 We have observed the field covering the error circle of
GRB090531B (Swift trigger 353728, GCN 9461(J. R. Cummings et al.))
with the unfiltered CCD camera on the 30-cm telescope
at University of Miyazaki.
 The observation was started 18:37:28 UT (92 s after the Swift trigger),
under cloudy condition.
First image was obtained at 18:41:05 UT (309 s after the Swift trigger).
 We have compared our data of 30 sec exposures with the USNO-A2.0 catalog.
There is no new source at the reported position.
(GCN 9462(B. E. Schaefer et al.), GCN 9464(C. Gronwall et al.)
 GCN 9465(T. N. Ukwatta et al.), GCN 9469(P. Schady et al.))

 Preliminary analysis shows there is no new source brighter than 14.6 mag.