TITLE: GCN CIRCULAR NUMBER: 9455 SUBJECT: GRB 090531: P60 Observations DATE: 09/05/31 07:07:45 GMT FROM: S. Bradley Cenko at Caltech S. B. Cenko (UC Berkeley) reports on behalf of a larger collaboration: We have imaged the field of GRB090531 (Stamatikos et al., GCN 9454) with the automated Palomar 60 inch telescope. Observations began at 4:47 UT on 2009 May 31 (~ 4.03 hr after the burst trigger) and were taken in the Sloan r', i', and z' filters. In coadded images, we find no new sources inside the BAT error circle to the following limits (calculated with reference to the SDSS DR7): Filter Magnitude Time Since Burst (hours) ---------------------------------------------------------------------- r' > 21.5 4.22 i' > 21.3 4.25 z' > 20.5 4.30