NOTE: uvot_fluxes_wget.pl vrs. 2018-01-16 fem at 180402d17h11m22s994030usUT
NOTE: Source region spec. is: 251.93358 -14.96858 4"
NOTE: Used archived XRT position of 251.93358 -14.96858  4.00
NOTE: position reference is GRB_Auto_Processing

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

GRB 180402A: Swift/UVOT Upper Limits

S.W.K. Emery (UCL-MSSL) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180402A
140 s after the BAT trigger (Lien et al., GCN Circ. 22580).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GRB_Auto_Processing ***
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          4328         4478          147         >20.8
u_FC               140          390          246         >19.7
white             4328         6805          407         >20.6
v                  423         5916          286         >19.2
b                 5101         6736          393         >20.2
u                  140         6531          845         >20.3
w1                4691         6326          393         >20.4
w2                5512         5712          197         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.77 in the direction of the burst
(Schlegel et al. 1998).