TITLE:   GCN CIRCULAR
NUMBER:  7702
SUBJECT: GRB080507: Swift/UVOT followup observations
DATE:    08/05/09 14:02:51 GMT
FROM:    Alice Breeveld at MSSL-UCL  <aad@mssl.ucl.ac.uk>

A. A. Breeveld (MSSL/UCL) and W. H. Baumgartner (GSFC/UMBC)
on behalf of the Swift/UVOT team.

The Swift Ultra-Violet/Optical Telescope (UVOT) started a ToO 
observation of GRB 080507 (Lapshov et al., GCN Circ. 7697) 109312s 
after the AGILE trigger. At the position of the afterglow candidate 
seen in the Tautenburg telescope (Kann et al. GCN Circ. 7701), which 
also corresponds to the  brightest source in the Swift XRT (V. Mangano 
et al. GCN Circ. 7699), the UVOT has a very faint source that does not 
appear in DSS or SDSS. It is only detectable in summed white images, 
but does NOT appear to be fading.

The limiting magnitudes for the initial exposure and detections in 
summed images are as follows:

Filter         T_start(s)  T_stop(s)  Exp(s)  Mag

white         109312  109526  211.4     >21.3 (UL)
white         109312  111881  2462.3   22.6 +/- 0.4 (3 sig)
white	111881  116511  1355.3   22.1 +/- 0.3 (3.8 sig)

The values quoted above are in the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) and are not corrected for galactic 
reddening.