TITLE:   GCN CIRCULAR
NUMBER:  5845
SUBJECT: GRB 061121: ART detection in Ic
DATE:    06/11/23 05:22:27 GMT
FROM:    Ken ichi Torii at Osaka U  <torii@ess.sci.osaka-u.ac.jp>

K. Torii (Osaka U.) reports on behalf of the ART collaboration:

 The error region of the bright GRB 061121 (Page et al. GCN
5823) was observed with the 14 inch ART-3a in Toyonaka. The
imaging started at about 5 minutes after the trigger while
the useful frames were obtained after 17:15 UT (t=113
minutes) when the object rose to 20 degrees above the horizon.

 The optical afterglow (GCN 5823) is detected at 3.2 sigma
in a stacked frame. Comparison with the USNO-B1.0 I2 mag
gave the following measurement.

-----------------------------------------
StartUT         Filter  Mag     Exposure
=========================================
17:15:24        Ic      18.1    60s x 100
=========================================