[vsnet-grb-info 4539] GRB 070419A: ROTSE-III Optical Limits
GCN Circulars
gcncirc at capella.gsfc.nasa.gov
Thu Apr 19 19:33:39 JST 2007
TITLE: GCN CIRCULAR
NUMBER: 6303
SUBJECT: GRB 070419A: ROTSE-III Optical Limits
DATE: 07/04/19 10:33:32 GMT
FROM: Brad Schaefer at LSU <schaefer at grb.phys.lsu.edu>
B. E. Schaefer (Louisiana State), F. Yuan (U Mich), S.A. Yost (U Mich),
report on behalf of the ROTSE collaboration:
ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB
070419A (Swift trigger 276205), producing images beginning 6.3 s after the
GCN notice time. An automated response took the first image at 10:00:47.3
UT, 81.2 s after the burst, under excellent conditions. We took 10 5-sec,
10 20-sec and 20 60-sec eposures, with further exposures still continuing.
These unfiltered images are calibrated relative to USNO A2.0 (R).
There is a bright star in the BAT error circle, but this is well removed
from the XRT position. Comparison to the DSS (second epoch) reveals no new
sources within the 3-sigma XRT error circle, for both single images and
coadding into sets of 10; the field is not crowded. Individual images
have limiting magnitudes ranging from 15.2-17.6; we set the following
specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
10:00:47.3 10:00:52.3 5 16.0 81.2 N
10:00:47.3 10:01:54.4 67 17.8 81.2 Y
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