NOTE: uvot_fluxes_wget.pl vrs. 2018-01-16 fem at 180221d15h23m27s548942usUT
NOTE: Source region spec. is: 326.772 -72.868 3"
NOTE: Used archived BAT position of 326.77200 -72.86800
NOTE: position reference is GCN_Position_Notice

=========== Draft Upper Limit Circular ========

GRB 180221: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and ***BA*** (***BA INSTITUTION***)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180221
2950 s after the BAT trigger (***Author*** et al., GCN Circ. ????).
No optical afterglow consistent with the BAT position
*** POSITION REFERENCE is GCN_Position_Notice ***
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          2950         3100          147         >19.7
white             2950        16220         2114         >21.4
v                 3931        10668          361         >19.2
b                 3315        15307         1260         >20.4
u                 3109         4745          393         >19.6
w1                4341         4541          197         >19.7
m2                4136         4335          197         >19.7
w2                3726        16401         1255         >20.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).