We present mass distributions obtained from near-infrared ( NIR ) surface brightness decompositions and rotation curve fitting of a sample of early-type spiral galaxies .
Bulge and disk mass-to-light ( M/L ) ratios , dark halo parameters , and the modified Newtonian dynamics ( MOND ) acceleration parameter are derived .
We find that the mean disk NIR M/L is higher than that of the bulge , and comparison with stellar population synthesis models implies that early-type spiral bulges are , on average , younger and more metal rich than disks .
NIR disk M/L is found to depend on disk luminosity , consistently with previously reported trends in ellipticals and spirals , and with cold dark matter models for disk formation .
Within the optical radius , the mean ratio of stellar to dark matter is 2 and the typical dark halo mass is 10 ^ { 11 } M _ { \odot } .
The value of the MOND acceleration parameter that best accommodates the sample as a whole is 1.3 \cdot 10 ^ { -8 } cm s ^ { -2 } .