[vsnet-grb-info 20763] GRB 180626A: KAIT Optical Upper Limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22861
SUBJECT: GRB 180626A: KAIT Optical Upper Limit
DATE:    18/06/26 19:58:36 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang at berkeley.edu>

WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to GRB 180626A (Evans et al.,
GCN 22850; Gotz et al., GCN 22851) starting at 08:23:31 UT, 135 s
after the Swift/BAT trigger. Observations were performed with an
automatic sequence in the clear (roughly R), V, and I filters,
and the exposure time was 20 s per image. Since the INTEGRAL trigger
was received earlier than the Swift trigger, KAIT responed to the
INTEGRAL trigger first. Unfortunately the UVOT afterglow location
(Evans et al., GCN 22850) is outside our field of view for the first
few images. We later manually re-pointed to the UVOT afterglow location
starting at 08:52:10 UT about 30 minutes after the Swift/BAT trigger,
with the updated exposure time of 60 s per image.
We do not detect the afterglow at the reported UVOT location
(Evans et al., GCN 22850) in our single image, nor in the co-added
images. The typical limiting magnitude of our single clear image is
about 19.5 mag calibrated to the PS1 catalog.