[vsnet-grb-info 5304] GRB 071025: Early Super-LOTIS Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6995
SUBJECT: GRB 071025: Early Super-LOTIS Observations
DATE:    07/10/25 09:54:28 GMT
FROM:    Grant Williams at Steward Observatory  <ggwilli at 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.