We present a detailed morphological , photometric , and kinematic analysis of two barred S0 galaxies with large , luminous inner disks inside their bars .
We show that these structures , in addition to being geometrically disk-like , have exponential profiles ( scale lengths \sim 300 –500 pc ) distinct from the central , non-exponential bulges .
We also find them to be kinematically disk-like .
The inner disk in NGC 2787 has a luminosity roughly twice that of the bulge ; but in NGC 3945 , the inner disk is almost ten times more luminous than the bulge , which itself is extremely small ( half-light radius \approx 100 pc , in a galaxy with an outer ring of radius \approx 14 kpc ) and only \sim 5 % of the total luminosity — a bulge/total ratio much more typical of an Sc galaxy . We estimate that at least 20 % of ( barred ) S0 galaxies may have similar structures , which means that their bulge/disk ratios may be significantly overestimated . 
These inner disks dominate the central light of their galaxies ; they are at least an order of magnitude larger than typical “ nuclear disks ” found in ellipticals and early-type spirals .
Consequently , they must affect the dynamics of the bars in which they reside .