TITLE:   GCN CIRCULAR
NUMBER:  40690
SUBJECT: EP250610A: Swift/UVOT Upper limits
DATE:    25/06/11 14:39:47 GMT
FROM:    Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>

M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of EP250610A 3 ks after the EP trigger (Zhang et al., GCN Circ. 40660). No optical afterglow consistent with the XRT position (Evans et al., GCN Circ. 40662) is seen in the initial UVOT exposures.

Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the exposures are: 

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag
u                 3087         9399         2103            >21.44
u                35617        41300         1846            >21.33

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).