
From Maiz Apellaniz 2006, AJ, 131, 1184

These are in photon units.

The B and V sensitivities are the same as Bessell (1990),
just converted to photon units, so we don't redo those.

The U band photon sensitivity has been re-calibrated based
on adjusting the filter shape to give consistent results 
between Vega and the spectrophotometric stars in the paper.
There is a significant change! (see figure 8).

The nice thing about this U band is that it also leads to
consistent results on the HST white dwarf scale (see
Holberg & Bergeron 2006, AJ, 132, 1221). Other descriptions
of the Landolt U band (e.g., Bessell or Cohen) do not 
give consistent results.

