GCN Circular 6995
Subject
GRB 071025: Early Super-LOTIS Observations
Event
Date
2007-10-25T09:54:28Z (19 years ago)
From
Grant Williams at Steward Observatory <ggwilli@gmail.com>
G. G. Williams (MMTO) and P. A. Milne (Steward Observatory), on behalf of the
Super-LOTIS Collaboration, report:
The robotic 0.6-m Super-LOTIS telescope began observing the error box
of GRB 071025 (Swift Trigger 295301, Pagani et al. GCN 6986) at
04:10:29.3 UT, 95 seconds after the trigger. Our initial observations
include 5 x 10s exposures, 5 x 20s exposures, and 30 x 60s exposures,
all in the R-band.
We detect the afterglow reported by Rykoff et al. (GCN 6987,
confirmed by Covino et al. GCN 6988) in the sum of our first ten 60s
exposures centered on 04:19:39 UT. We do not detect the afterglow in
our single 10s or 20s exposures. Using USNO-B1.0 stars we estimate the
following R-band magnitude and upper limits for the OT:
t_start (UT) t_mid (UT) exp t (s) t_start-t_0 (s) R Mag
-----------------------------------------------------------------------------------------------------
04:10:29.3 04:10:34.3 10 95.3 R > 17.3
04:13:42.1 04:13:52.1 20 288.1 R > 17.8
04:14:08.8 04:19:39.0 600 314.8 R =
17.97 +/- 0.17
Our upper limit of R > 17.8 was measured near the time of the
unfiltered m=17.3 peak reported by Rykoff et al. (GCN 6992).
Additional observations and analysis are ongoing.