Angular momentum and galaxy formation revisited: Effects of variable mass-to-light ratios

Abstract

We rederive the relation between the specific angular momentum j and the mass M of the stellar matter in galaxies of different morphological types. This is a revision of the j -M diagram presented in our recent comprehensive study of galactic angular momentum. In that work, we estimated j from kinematic and photometric data that extended to large radii and M from near-infrared luminosities LK with an assumed universal mass-to-light ratio M /LK . However, recent stellar population models show large variations in M /LK correlated with B-V color. In the present work, we use this correlation to estimate M /LK and hence M from the measured B-V and LK . Our revised j -M diagram is similar to our previous one; both disk-dominated and elliptical galaxies follow nearly parallel sequences with and α = 0.6 ± 0.1. However, the offset between the sequences is now a factor of about 5, some 30% larger than before (and close to the offset found by Fall in 1983). Thus, our new results place even tighter constraints on the loss of specific angular momentum by galactic disks over their lifetimes. © 2013. The American Astronomical Society. All rights reserved.