학술논문
SDSS-IV MaNGA: Environmental dependence of the Mgb/-sigma_* relation for nearby galaxies
Document Type
Working Paper
Author
Source
The Astrophysical Journal, Volume 873, Issue 1, article id. 63, 15 pp. (2019)
Subject
Language
Abstract
We use a sample of ~3000 galaxies from the MaNGA MPL-7 internal data release to study the alpha abundance distribution within low-redshift galaxies. We use the Lick index ratio Mgb/ as an alpha abundance indicator to study relationships between the alpha abundance distribution and galaxy properties such as effective stellar velocity dispersion within 0.3 effective radii (sigma_*), galaxy environment, and dark matter halo formation time (z_f). We find that (1) all galaxies show a tight correlation between Mgb/ and sigma_*; (2) `old' (H_beta < 3) low-sigma_* galaxies in high local density environment and inner regions within galaxy groups are enhanced in Mgb/, while `young' (H_beta>3) galaxies and high-mass galaxies show no or less environmental dependence; (3) `old' galaxies with high-z_f show enhanced Mgb/ over low- and medium-z_f; (4) Mgb/ gradients are close to zero and show dependence on sigma_* but no obvious dependence on the environment or z_f. Our study indicates that stellar velocity dispersion or galaxy mass is the main parameter driving the Mgb/ enhancement, although environments appear to have modest effects, particularly for low- and medium-mass galaxies.
Comment: Accepted for publication in ApJ
Comment: Accepted for publication in ApJ