Abstract
A large number of observational parameters for the Rubin et al. sample of 60 spiral galaxies, ranging from Sa to Sc, have been compiled. A principal component analysis carried out on this sample shows that about 85 percent of the observational variance in the most important observational properties can be explained by two dimensions. This leads to an objective method for the determination of the optimal two-dimensional classification system, tentatively identified as the ‘scale’ (a combination of the B-H color and the absolute radius at the 25th B mag/sq arcsec isophote) and the ‘form’ (a combination of the B-H color and the bulge-to-total light ratio). Based on this approach it is shown that DDO luminosity classes exhibit very strong correlations with almost all of the other parameters; this suggests that the arm structure is closely linked to the structure and dynamics of spiral galaxies. In addition, a correlation between DDO class and the outer gradient of the rotation curve is found.
Author
Whitmore, B. C.
Journal
Astrophysical Journal
Paper Publication Date
March 1984
Paper Type
Astrostatistics