TITLE:   GCN CIRCULAR
NUMBER:  6436
SUBJECT: GRB070521: P200 Observations
DATE:    07/05/21 08:54:12 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

A. Rau, M. M. Kasliwal, and S. B. Cenko (Caltech) report on behalf of a
larger collabortation:

We obtained R-band photometry of GRB070521 with the Large Format
Camera mounted on the Palomar 200-inch telescope. Observations started 29
min post-burst and lasted 3x300s. Calibration was performed relative to
the SDSS (Cool et al.; GCN 6432).

We find no source in the XRT error circle (Guidorzi et al. 2007; GCN 6431)
to a limiting magnitude of R>23.3.