TITLE:   GCN CIRCULAR
NUMBER:  6730
SUBJECT: GRB 070808: Swift/UVOT upper limits
DATE:    07/08/09 22:21:31 GMT
FROM:    Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and J.R. Cummings (NASA/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT observed the field of GRB 070808 starting 119 s after
the BAT trigger (Cummings et al., GCN Circ. 6718).  We do not find a source
in any of the UVOT observations inside the refined XRT error circle
(Starling and Cummings, GCN Circ. 6725). The 3-sigma upper limits for detecting
a source in the first finding chart (FC) exposure and co-added frames are:

Filter            T_start(s)   T_stop(s)     Exp(s)     Mag (3-sigma UL)

white (FC)        119          218           98         >20.6
white             119          7539          628        >20.9
v                 225          6515          1051       >20.4
b                 704          7334          461        >20.5
u                 680          7129          490        >20.6
uvw1              655          6925          490        >20.3
uvm2              783          6720          452        >20.9
uvw2              734          7625          353        >20.8

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E(B-V) = 0.02 mag in
the direction of the burst (Schlegel et al. 1998).