We have measured the central structural properties for a sample of S0-Sbc galaxies down to scales of \sim 10 pc using Hubble Space Telescope 
NICMOS images .
We find that the photometric masses of the central star clusters , which occur in 58 % of our sample , are related to their host bulge masses such that { \cal M } _ { \mathrm { PS } } = 10 ^ { 7.75 \pm 0.15 } ( { \cal M } _ { \mathrm { Bul } } / 10 ^ { 10 } { % \cal M } _ { \odot } ) ^ { 0.76 \pm 0.13 } .
Put together with recent data on bulges hosting supermassive black holes , we infer a non-linear dependency of the ‘ Central Massive Object ’ mass on the host bulge mass such that { \cal M } _ { \mathrm { CMO } } / { \cal M } _ { \odot } = 10 ^ { 7.51 \pm 0.06 } ( { \cal M } _ { \mathrm { % Bul } } / 10 ^ { 10 } { \cal M } _ { \odot } ) ^ { 0.84 \pm 0.06 } .
We argue that the linear relation presented by Ferrarese et al .
is biased at the low-mass end by the inclusion of the disc light from lenticular galaxies in their sample .
Matching our NICMOS data with wider-field , ground-based K -band images enabled us to sample from the nucleus to the disk-dominated region of each galaxy , and thus to perform a proper bulge-disk decomposition .
We found that the majority of our galaxies ( \sim 90 % ) possess central light excesses which can be modeled with an inner exponential and/or an unresolved point source in the case of the nuclear star clusters .
All the extended nuclear components , with sizes of a few hundred pc , have disky isophotes , which suggest that they may be inner disks , rings , or bars ; their colors are redder than those of the underlying bulge , arguing against a recent origin for their stellar populations .
Surface brightness profiles ( of the total galaxy light , and the bulge component on its own ) rise inward to the resolution limit of the data , with a continuous distribution of logarithmic slopes from the low values typical of dwarf ellipticals ( 0.1 \leq \gamma \leq 0.3 ) to the high values ( \gamma \sim 1 ) typical of intermediate luminosity ellipticals ; the nuclear slope bi-modality reported by others is not present in our sample .