We construct a large data set of global structural parameters for 1300 field
and cluster spiral galaxies and explore the joint distribution of luminosity L,
optical rotation velocity V, and disk size R at I- and 2MASS K-bands. The I-
and K-band velocity-luminosity (VL) relations have log-slopes of 0.29 and 0.27,
respectively with sigma_ln(VL)~0.13, and show a small dependence on color and
morphological type in the sense that redder, early-type disk galaxies rotate
faster than bluer, later-type disk galaxies for most luminosities. The VL
relation at I- and K-bands is independent of surface brightness, size and light
concentration. The log-slope of the I- and K-band RL relations is a strong
function of morphology and varies from 0.25 to 0.5. The average dispersion
sigma_ln(RL) decreases from 0.33 at I-band to 0.29 at K, likely due to the
2MASS selection bias against lower surface brightness galaxies. Measurement
uncertainties are sigma_ln(V)~0.09, sigma_ln(L)~0.14 and somewhat larger and
harder to estimate for ln(R). The color dependence of the VL relation is
consistent with expectations from stellar population synthesis models. The VL
and RL residuals are largely uncorrelated with each other; the RV-RL residuals
show only a weak positive correlation. These correlations suggest that scatter
in luminosity is not a significant source of the scatter in the VL and RL
relations. The observed scaling relations can be understood in the context of a
model of disk galaxies embedded in dark matter halos that invokes low mean spin
parameters and dark halo expansion, as we describe in our companion paper
(Dutton et al. 2007). We discuss in two appendices various pitfalls of standard
analytical derivations of galaxy scaling relations, including the Tully-Fisher
relation with different slopes. (Abridged).Comment: Accepted for publication at ApJ. The full document, with
high-resolution B&W and colour figures, is available at
http://www.astro.queensu.ca/~courteau/papers/VRL2007ApJ.pdf . Our data base
for 1303 spiral galaxies is also available at
http://www.astro.queensu.ca/~courteau/data/VRL2007.da