Revisiting the Stellar Mass–Angular Momentum–Morphology Relation: Extension to Higher Bulge Fraction and the Effect of Bulge Type

Abstract

We present the relation between stellar specific angular momentum j * , stellar mass M * , and bulge-to-total light ratio β for The H i Nearby Galaxy Survey, the Calar Alto Legacy Integral Field Area Survey, and Romanowsky & Fall data sets, exploring the existence of a fundamental plane between these parameters, as first suggested by Obreschkow & Glazebrook. Our best-fit M * – j * relation yields a slope of α  = 1.03 ± 0.11 with a trivariate fit including β . When ignoring the effect of β , the exponent α  = 0.56 ± 0.06 is consistent with α  = 2/3 that is predicted for dark matter halos. There is a linear β – j * / M * relation for β  ≲ 0.4, exhibiting a general trend of increasing β with decreasing j * / M * . Galaxies with β  ≳ 0.4 have higher j * than predicted by the relation. Pseudobulge galaxies have preferentially lower β for a given j * / M * than galaxies that contain classical bulges. Pseudobulge galaxies follow a well-defined track in β – j * / M * space, consistent with Obreschkow & Glazebrook, while galaxies with classical bulges do not. These results are consistent with the hypothesis that while growth in either bulge type is linked to a decrease in j * / M * , the mechanisms that build pseudobulges seem to be less efficient at increasing bulge mass per decrease in specific angular momentum than those that build classical bulges.