NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 240311d22h47m34s168472usUT
NOTE: Source region spec. is: 299.8956 +34.5764 4"
NOTE: Used archived XRT position of 299.89560  34.57640  4.00
NOTE: position reference is GCN_Notice
WARNING: t_start for light curve (3761) and t_start from the exposure report (174) do not agree.
  Replace ??? in draft Circular with correct value.

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

GRB 240311: Swift/UVOT Upper Limits

S. R. Oates (U.Birmingham) and ***BA*** (***BA INSTITUTION***)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240311
***???*** s after the BAT trigger (***Author*** et al., GCN Circ. ????).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_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 initial exposures are:

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

white             3966         4166          197         >20.0
v                 4377         4577          197         >18.6
b                 3761         3961          197         >19.8
u                 4992         5174          179         >19.9
w1                4788         4988          197         >19.2
m2                4582         4782          197         >20.0
w2                4172         4372          197         >19.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.795 in the direction of the burst
(Schlegel et al. 1998).