GCN Circular 6328
Subject
GRB 070419A: Early Super-LOTIS Observations
Date
2007-04-20T04:03:14Z (17 years ago)
From
Grant Williams at Steward Observatory <ggwilli@mmto.org>
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 070419A (Swift Trigger 276205, Stamatikos et al. GCN 6302) at
10:01:08.1 UT, 102 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 Chornock et al. (GCN 6304) in our
third (and subsequent) 60 second exposure which began at 10:07:01.8 UT,
456 seconds after the trigger. We do not detect the afterglow in early
single exposures or early summed exposures. This is evidently related to
the brightening reported by Cenko et al. & Wren et al. (GCN 6306 & 6324).
Using the USNO-B star at RA=12:10:57.57, Dec=+39:55:40.2 with R=15.22
(Cenko et al. GCN 6306), we calculate the following R-band magnitudes and
5-sigma upper limits:
t_start (UT) exp t_tot (s) Nsum t_start-t_0 (s) R Mag
----------------------------------------------------------------
10:01:08.1 10 1 102 R > 17.71
10:01:08.1 50 5 102 R > 18.58
10:02:33.1 20 1 187 R > 18.24
10:02:33.1 100 5 187 R > 19.19
10:04:47.9 60 1 322 R > 18.60
10:07:01.8 60 1 456 R = 18.49 +/- 0.22
Additional observations followed our initial set and analysis are ongoing.