TITLE:   GCN CIRCULAR
NUMBER:  28222
SUBJECT: GRB 200806A: Swift/UVOT Possible Detection
DATE:    20/08/07 17:37:59 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and E. Ambrosi (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 200806A
86 s after the BAT trigger (Ambrosi et al., GCN Circ. 28211).
A source consistent with the enhanced XRT position
(Beardmore et al. GCN Circ. 28214)
is marginally detected in the initial UVOT exposures.

The preliminary detection and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:

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

white               86          236          147         20.26 +/- 0.28
v                  629          821           39        >17.9
b                  555          747           39        >19.3
u                  300          722          265        >19.5
w1                 678          870           39        >18.8
m2                 653          845           39        >19.4
w2                 604         1052           58        >19.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.42 in the direction of the burst
(Schlegel et al. 1998).