[vsnet-grb-info 7921] Initial Swift/UVOT observations of GRB 090531B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9464
SUBJECT: Initial Swift/UVOT observations of GRB 090531B
DATE:    09/05/31 20:49:26 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl at astro.psu.edu>

C. Gronwall (PSU) and J. R. Cummings (NASA/UMBC) report on behalf of  
the UVOT Team:

In response to GRB090531B (Swift/BAT trigger 353728; Cummings et al.,  
GCN Circ. 9461)
at 18:35:56 UT, UVOT took a finding chart exposure of 150 seconds with  
the White filter
starting 3848 seconds after the BAT trigger. No credible afterglow  
candidate has been
found in the initial data products. The 2.7'x2.7' sub-image covers  
100% of the XRT
error circle (Sbarufatti et al., GCN Circ. 9463) The typical 3-sigma  
upper limit has
been about 19.6 mag.  No correction has been made for the expected  
extinction corresponding
to E(B-V) of 1.12.