[vsnet-grb-info 7703] GRB 090426, RIMOTS optical upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9257
SUBJECT: GRB 090426, RIMOTS optical upper limits
DATE:    09/04/26 15:53:43 GMT
FROM:    Kenta Kono at Miyazaki U  <kenta0514 at astro.miyazaki-u.ac.jp>

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

 We have observed the field covering the error circle of
GRB090426 (Swift trigger 350479, GCN 9254, J. R. Cummings et al.) 
with the unfiltered CCD camera on the 30-cm telescope 
at University of Miyazaki.
The observation was started 12:50:29 UT (1.7 min. after the Swift trigger), 
under cloudy condition.
First analyzable image was obtained at 12:57:06 UT (6.5 min. 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 9254, J. R. Cummings et al.)

the upper limits are as follows:
--------------------------------------------------------------
Start(UT)   End(UT)    Num. of frames    Limit (mag.)
--------------------------------------------------------------
12:57:06    12:57:36          1            15.3
12:57:06    13:17:26         10            16.8
---------------------------------------------------------------