The weak imprint of environment on the stellar populations of galaxies
Abstract
We investigate the environmental dependence of the stellar populations of galaxies in Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Echoing earlier works, we find that satellites are both more metal-rich (<0.1 dex) and older (<2 Gyr) than centrals of the same stellar mass. However, after separating star-forming, green valley, and passive galaxies, we find that the true environmental dependence of both stellar metallicity (<0.03 dex) and age (<0.5 Gyr) is in fact much weaker. We show that the strong environmental effects found when galaxies are not differentiated result from a combination of selection effects brought about by the environmental dependence of the quenched fraction of galaxies, and thus we strongly advocate for the separation of star-forming, green valley, and passive galaxies when the environmental dependence of galaxy properties are investigated. We also study further environmental trends separately for both central and satellite galaxies. We find that star-forming galaxies show no environmental effects, neither for centrals nor for satellites. In contrast, the stellar metallicities of passive and green valley satellites increase weakly (<0.05 and <0.08 dex, respectively) with increasing halo mass, increasing local overdensity and decreasing projected distance from their central; this effect is interpreted in terms of moderate environmental starvation (‘strangulation’) contributing to the quenching of satellite galaxies. Finally, we find a unique feature in the stellar mass–stellar metallicity relation for passive centrals, where galaxies in more massive haloes have larger stellar mass (∼0.1 dex) at constant stellar metallicity; this effect is interpreted in terms of dry merging of passive central galaxies and/or progenitor bias.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 13, 2020
- Source ID
- 10.1093/mnras/staa3545
Entities
People
- Claudia Maraston
- Daniel Goddard
- Daniel Thomas
- James Trussler
- Jianhui Lian
- Roberto Maiolino
- Yingjie Peng
Organizations
- Alfred P. Sloan Foundation
- American Museum of Natural History
- Case Western Reserve University
- Chinese Academy of Sciences
- Drexel University
- European Research Council
- Higher Education Funding Council for England
- Institute for Advanced Study
- Johns Hopkins University
- Los Alamos National Laboratory
- Max Planck Society
- National Aeronautics and Space Administration
- National Natural Science Foundation of China
- National Science Foundation
- New Mexico State University
- Ohio State University
- Peking University
- Princeton University
- Science and Technology Facilities Council
- United States Department of Energy
- United States Naval Observatory
- University College London
- University of Basel
- University of Cambridge
- University of Chicago
- University of Pittsburgh
- University of Portsmouth
- University of Utah
- University of Washington