2010/04/22 by Arjen van der Wel, Eric F. Bell, B. Holden +5 · 1 citation
Computer Science · Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Dark matter #Dark matter halo #Data Visualization and Analytics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Galaxy group #Halo #Physics #Sky #Star formation #Stellar mass #astro-ph.CO
paper · pdf · doi:10.1088/0004-637x/714/2/1779
published as van der Wel et al. 2010, ApJ, 714, 1779 · published in ApJ: http://adsabs.harvard.edu/abs/2010ApJ...714.1779V
openalex publication_date 2010/04/22 · arxiv created 2010/04/26 · arxiv updated 2010/04/28 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We provide a physical interpretation and explanation of the morphology–density relation for galaxies, drawing on stellar masses, star formation rates, axis ratios, and group halo masses from the Sloan Digital Sky Survey. We first re-cast the classical morphology–density relation in more quantitative terms, using low star formation rate (quiescence) as a proxy for early-type morphology and dark matter halo mass from a group catalog as a proxy for environmental density: for galaxies of a given stellar mass the quiescent fraction is found to increase with increasing dark matter halo mass. Our novel result is that—at a given stellar mass—quiescent galaxies are significantly flatter in dense environments, implying a higher fraction of disk galaxies. Supposing that the denser environments differ simply by a higher incidence of quiescent disk galaxies that are structurally similar to star-forming disk galaxies of similar mass, explains simultaneously and quantitatively these quiescence–environment and shape–environment relations. Our findings add considerable weight to the slow removal of gas as the main physical driver of the morphology–density relation, at the expense of other explanations.