TITLE:   GCN CIRCULAR
NUMBER:  8819
SUBJECT: GRB090117 Swift/UVOT upper limits
DATE:    09/01/18 03:23:36 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>

P. Schady (MSSL-UCL) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began observing the field of SuperAGILE GRB 090117  
(Donnarumma et al., GCN 8817) at 2009-01-017 19:10:14 UT, 13.7 ks  
after the burst. We do not detect any source at the Swift XRT position  
(Beardmore et al., GCN 8818), although we note that there is a bright  
star with v-band magnitude v = 17.7 that lies within the XRT error  
circle.

The UVOT 3-sigma upper limits are reported below:

Filter   T_start   Exp(s)  Mag (3-sigma upper limit)
-------------------------------------------------------------
white      14.4       455      > 17.18
v              15.1       595      > 16.18
b              13.8       627      > 17.08
u              13.7       63        > 17.27
-------------------------------------------------------------

The quoted upper limits have not been corrected for the expected  
Galactic extinction along the line of sight of E_(B-V) = 1.63 mag. All  
photometry is on the UVOT photometric system described in Poole et al.  
(2008, MNRAS, 383, 627).