GCN Circular 6586
Subject
GRB 070628: Watcher Observations
Date
2007-06-28T21:56:11Z (18 years ago)
From
Gary Melady at UCD <gmelady@bermuda.ucd.ie>
Gary Melady (University College Dublin), John French (UCD),
Petr Kubanek (GACE Valencia), Martin Jelinek (IAA CSIC Granada)
report on behalf of the Watcher collaboration:
The Watcher 40cm robotic telescope, located at Boyden Observatory,
South Africa, responded to Swift Trigger 283320 (GRB 070628, Holland et al.
GCN 6584). when the dome opened at 15:17:29 UT, 36.43 minutes after the
trigger. However the bright evening sky rendered the earliest images
unusable.
An unfiltered 60s exposure taken under twilight conditions at 16:12:48 UT,
91.76 minutes after the Swift trigger, showed no new source in the UVOT
error box (as reported by Gronwall et al., GCN 6585) down to an R-band
limiting magnitude of approx 16.2 (in comparison to USNO-B1).
We combined 27 subsequent 60s exposures to create a 1620s unfiltered image with
an exposure mid-time of 16:28:05 (108.05 minutes after the trigger). The later
images were taken at high air mass as the target was setting. This shows no new
source in the error box down to an R-band limiting magnitude of approx 17.2.
The target set at our location at 18:20 UT so no further observations will be made.
This message may be cited.