GCN Circular 9880
Subject
GRB 090904A: ROTSE-III Optical Limits
Date
2009-09-04T01:25:32Z (15 years ago)
From
Shashi Bhushan Pandey at ROTSE <shaship@umich.edu>
S. B. Pandey (U Mich), W. Rujopakarn (Steward), W. Zheng (U Mich) report on
behalf of the ROTSE collaboration:
ROTSE-IIId, located at the Turkish National Observatory at Bakirlitepe,
Turkey, responded to GRB 090904A (Swift trigger 361830; Perri M., GCN
9879), producing images beginning 9.5 s after the GCN notice time. An
automated response took the first image at 01:02:31.6 UT, 84.7 s after the
burst, and during the gamma-ray emission, under fair conditions. We took 10
5-sec, 10 20-sec and 10 60-sec exposures. These unfiltered images are
calibrated relative to USNO A2.0 (R). Imaging is on going.
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle or the XRT error circle, for both single
images and coadding into sets of 10. Individual images have limiting
magnitudes ranging from 15.8-16.6; we set the following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
01:02:31.5 01:02:36.5 5 15.8 84.6 N
01:04:48.1 01:09:27.0 278 17.8 221.2 Y