SDSS-IV MaNGA: Uncovering the Angular Momentum Content of Central and Satellite Early-type Galaxies

TL;DR

This study analyzes the angular momentum of central and satellite early-type galaxies using MaNGA data, revealing a strong dependence on stellar mass and minimal differences between galaxy types after accounting for mass and classification errors.

Contribution

It provides the first detailed comparison of angular momentum content between central and satellite early-type galaxies, accounting for classification uncertainties and halo mass effects.

Findings

High-mass galaxies (>10^11 M_sun) mostly have little rotation.

Lower-mass galaxies show significant net rotation.

No significant residual difference in angular momentum between centrals and satellites after matching for mass.

Abstract

We study 379 central and 159 satellite early-type galaxies with two-dimensional kinematics from the integral-field survey Mapping Nearby Galaxies at APO (MaNGA) to determine how their angular momentum content depends on stellar and halo mass. Using the Yang et. al. (2007) group catalog, we identify central and satellite galaxies in groups with halo masses in the range 10^12.5 h^-1 M_sun < M_200b < 10^15 h^-1 M_sun. As in previous work, we see a sharp dependence on stellar mass, in the sense that ~ 70% of galaxies with stellar mass M_* > 10^11 h^-2 M_sun tend to have very little rotation, while nearly all galaxies at lower mass show some net rotation. The ~ 30% of high-mass galaxies that have significant rotation do not stand out in other galaxy properties except for a higher incidence of ionized gas emission. Our data are consistent with recent simulation results suggesting that major merging and gas accretion have more impact on the rotational support of lower-mass galaxies. When carefully matching the stellar mass distributions, we find no residual differences in angular momentum content between satellite and central galaxies at the 20\% level. Similarly, at fixed mass, galaxies have consistent rotation properties across a wide range of halo mass. However, we find that errors in classification of centrals and satellites with group finders systematically lowers differences between satellite and central galaxies at a level that is comparable to current measurement uncertainties. To improve constraints, the impact of group finding methods will have to be forward modeled via mock catalogs.