TITLE:   GCN CIRCULAR
NUMBER:  19756
SUBJECT: GRB 160801A: Swift/UVOT Upper Limits
DATE:    16/08/02 20:48:04 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

B. G. Balzer (PSU) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160801A
90 s after the BAT trigger (D'Elia et al., GCN Circ. 19744).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 19746)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and the subsequent summed exposures:

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

white_FC            90          240          147         >20.50
u_FC               302          552          245         >19.91
white              581         1896          283         >20.94
v                  631         1945          155         >18.91
b                  557         1871          136         >19.90
u                  704         1846          116         >19.48
w1                1455         1474           19         >17.77

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).