TITLE:   GCN CIRCULAR
NUMBER:  28555
SUBJECT: GRB 201001A: Swift/UVOT Upper Limits
DATE:    20/10/03 19:24:16 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

A. Belles (PSU) and K. K. Simpson (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 201001A
120 s after the BAT trigger (Simpson et al., GCN Circ. 28539).
No optical afterglow consistent with the XRT position
(Simpson et al. GCN Circ. 28539)
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 subsequent exposures are:

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

white_FC           120          270          147         >21.1
u_FC               279          529          246         >19.8
white              120         1525          392         >21.1
v                  611         1575          117         >18.8
b                  535         1501           97         >18.9
u                  279         1476          324         >19.8
w1                 660         1452           97         >19.1
m2                 635         1427           97         >19.7
w2                 586         1550          117         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.12 in the direction of the burst
(Schlegel et al. 1998).