Title:Mass-Luminosity Profile in Spiral Galaxies

Abstract:
We study the relationship between Kinematics and NIR Surface Brightness in a 
sample of 22 spiral galaxies. We analyze the uncertainties involved in the 
determination of mass and luminosities from the velocity and brightness 
observations, and derive the Mass-Luminosity Ratios (M/L) as a function of 
radius. These profiles present a constant M/L value in the radial ranges where 
the photometric disk appears dominant. However, in the central region the 
profiles present a negative gradient. Finally, we analyze how the observational 
bias could affect the determination of the dark halo density profile. The halo 
density profile is strongly dependent on the M/L value adopted for the bulge 
component which itself is severely affected by dust extinction and age and 
metallicity gradients.