GCN Circular 7530

P. Ward (MSSL-UCL), P. Schady (MSSL-UCL) and M. Perri (ASDC) report on  
behalf of the Swift-UVOT team

The Swift/UVOT observed the field of GRB 080328 starting 110s after  
the BAT trigger (Perri et al., GCN 7525
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 ). The afterglow is detected at

RA:      05h 21m 55.87s
DEC:  +47d 30' 39.4"

only in the white and v filters, with an error radius of 0.6 arcsec  
(90% confidence).
The afterglow is seen to decay in both these filters, and has the  
following magnitudes and 3-sigma upper limits (in the UVOT photometric  
system, Poole et al. (2008, MNRAS, 383, 627)).

Filter	Tstart(s) 	Exp(s)	 Magnitude

white	110		99.8	17.84 +/- 0.05
white	867		99.8	20.43 +/- 0.27
white	5611	399.8	> 21.60
v		217		399.8	17.90 +/- 0.08
v		973		399.8	19.25 +/- 0.20
v		6023	399.8	> 20.00 	

The afterglow is not detected in any other filters, perhaps due to the  
high Galactic extinction value of  E(B-V) = 0.58 mag. The following  
are the 3-sigma upper limits for these filters.

Filter	Tstart(s) 	Exp(s)	 Magnitude

b		851		493.6      > 20.96
u 		673		338.5   	> 20.59
uvw1	648		362.8  	> 20.54
uvm2	623		393.2	> 20.38
uvw2	728		498.5  	> 20.88

The values quoted above are not corrected for Galactic extinction  
corresponding to a reddening of E(B-V) = 0.58 mag in the direction of  
the burst (Schlegel et al. 1998).