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SDSS-IV MaNGA: Environmental dependence of the Mgb/<Fe>-sigma_* relation for nearby galaxies

Authors :
Zheng, Zheng
Li, Cheng
Mao, Shude
Wang, Huiyuan
Liu, Chao
Mo, Houjun
Yuan, Zhen
Maraston, Claudia
Thomas, Daniel
Yan, Renbin
Bundy, Kevin
Long, R. J.
Parikh, Taniya
Oyarzun, Grecco
Bizyaev, Dmitry
Lacerna, Ivan
Source :
The Astrophysical Journal, Volume 873, Issue 1, article id. 63, 15 pp. (2019)
Publication Year :
2019

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/&lt;Fe&gt; 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/&lt;Fe&gt; and sigma_*; (2) `old&#39; (H_beta &lt; 3) low-sigma_* galaxies in high local density environment and inner regions within galaxy groups are enhanced in Mgb/&lt;Fe&gt;, while `young&#39; (H_beta&gt;3) galaxies and high-mass galaxies show no or less environmental dependence; (3) `old&#39; galaxies with high-z_f show enhanced Mgb/&lt;Fe&gt; over low- and medium-z_f; (4) Mgb/&lt;Fe&gt; 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/&lt;Fe&gt; enhancement, although environments appear to have modest effects, particularly for low- and medium-mass galaxies.&lt;br /&gt;Comment: Accepted for publication in ApJ

Details

Database :
arXiv
Journal :
The Astrophysical Journal, Volume 873, Issue 1, article id. 63, 15 pp. (2019)
Publication Type :
Report
Accession number :
edsarx.1902.07387
Document Type :
Working Paper
Full Text :
https://doi.org/10.3847/1538-4357/ab03d2