GCN Circular 6495
Subject
GRB 070611: ROTSE-III Optical Limits
Date
2007-06-11T02:31:23Z (18 years ago)
From
Brad Schaefer at LSU <schaefer@grb.phys.lsu.edu>
Bradley E. Schaefer (Louisiana State), S.A. Yost (U Mich), E.S. Rykoff (U
Mich), and F. Yuan (U Mich) report on behalf of the ROTSE collaboration:
ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,
responded to GRB 070611 (Swift trigger 282003; M. C. Stroh et al. 2007,
GCN 6494), producing images beginning 7.6 s after the GCN notice time. An
automated response took the first image at 01:57:58.6 UT, 44.7 s after the
burst, under excellent conditions. We took 10 5-sec, 10 20-sec and 20
60-sec exposures, with further exposures now ongoing. These unfiltered
images are calibrated relative to USNO A2.0 (R).
Comparison to the DSS (second epoch) reveals no new sources within the
3-sigma Swift/BAT error circle; the field is not crowded. Individual
images have limiting magnitudes ranging from 15.7-17.2; we set the
following specific limits.
start UT end UT t_exp(s) mlim t_start-tGRB(s) Coadd?
--------------------------------------------------------------------
01:57:58.6 01:58:03.6 5 15.8 44.7 N
01:57:58.6 01:59:16.6 78 17.0 44.7 Y
02:04:20.5 02:15:45.2 684 18.3 426.6 Y