TITLE:   GCN CIRCULAR
NUMBER:  32315
SUBJECT: GRB 220701A: Keck/LRIS Optical Upper Limit
DATE:    22/07/02 10:47:23 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng, Yi Yang, Thomas G. Brink and Alexei V. Filippenko
(UC Berkeley) report on behalf of the KAIT GRB team:

We observed the field of GRB 200701A (Evans al., GCN 32306) with the
Low Resolution Imaging Spectrometer (LRIS) mounted on the 10-m Keck I
telescope, started at 10:41 UT on July 1st (5.82 hours after the burst).
We obtained 5x180s exposure in g and RG850 (close to z) filter
simultaneously,
under the averaged seeing ~1.2". We do not detect any optical afterglow
candidate within the enhanced XRT position error circle (Evans al., GCN
32308)
with the following upper limit, calibrated to the Pan-STARRS1 catalog in
g and z filter:

g > 24.5
z > 22.8

Our result is consistent with other non-detections (Zheng et al. GCNC 32307;
O'Connor et al., GCN 32309; Oates et al., GCN 32310; Hu et al., GCN 32311,
Strausbaugh et al., GCN 32313).