GCN Circular 9150
Subject
GRB 090418: ROTSE-III Confirmation of Optical Counterpart
Date
2009-04-18T12:10:59Z (15 years ago)
From
Fang Yuan at ROTSE <yuanfang@umich.edu>
F. Yuan (U Mich), B. E. Schaefer (Louisiana State), W. Rujopakarn
(Steward), report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
090418 (Swift trigger 349510; Mangano et al, GCN 9149) in twilight.
The first image was at 11:07:59.2 UT, 19.0 s after the burst (4.2 s
after the GCN notice time). The unfiltered images are calibrated
relative to USNO B1.0.
We detect the optical counterpart at the KAIT and UVOT position
(Chornock et al. GCN 9148; Mangano et al, GCN 9149) at the following
magnitude and limit:
start UT end UT mag magerr mlim(of image)
--------------------------------------------------------------------------------
11:07:59.2 11:09:06.3 15.9 0.1 17.0
11:09:19.6 11:14:02.1 15.9 0.1 16.8
11:14:11.3 11:25:31.5 - - 16.7