We present near-infrared ( NIR ) surface photometry of a sample of 14 early-type spirals with observed rotation curves .
In this first paper , we report the results of two-dimensional parametric and non-parametric decompositions to separate the bulge and disk components ; the parametric bulge is modeled with a generalized exponential law of integer index n , and the disk with a simple exponential .
We find that the derived bulge parameters , for a given galaxy , vary systematically with the bulge shape index n .
The mean early-type bulge has a best-fit n = 2.6 , and 80 % of the sample has best n of 2 or 3 .
Bulges are rarely spherical ; the median bulge intrinsic ellipticity is 0.33 .
The median early-type disk has ( J - K ) _ { d } more than 0.1 mag bluer than the bulge , and a NIR disk surface brightness more than 1 mag arcsec ^ { -2 } brighter than later-type disks .
Our data are consistent with the well-established correlation of both bulge and disk surface brightness with physical scale length , and we note that the location of bulges within this projection of the fundamental plane depends on their shape index n .
In agreement with previous work , the ratios of bulge and disk scale lengths are consistent with a constant value r _ { e } / r _ { d } = 0.3 ; however , such value again depends on the bulge index n , implying that claims for a scale-free Hubble sequence may be premature .