Correlations among global photometric properties of disk galaxies

Using a two-dimensional galaxy image decomposition technique, we extract global bulge and disk parameters for a complete sample of early-type disk galaxies in the near-infrared K band. We find significant correlation of the bulge parameter n with the central bulge surface brightness mu(b)(0) and with effective radius r(e). Using bivariate analysis techniques, we find that log n, log r(e), and mu(b)(0) are distributed in a plane with small scatter. We do not find a strong correlation of n with bulge-to-disk luminosity ratio, contrary to earlier reports. For these early-type disk galaxies, r(e) and the disk scale length r(d) are well correlated, but with large scatter. We examine the implications of our results for various bulge formation scenarios in disk galaxies.