2006/06/23 by David W. Hogg, Morad Masjedi, Andreas A. Berlind +3 · 2 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Elliptical galaxy #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Galaxy group #Lenticular galaxy #Luminous infrared galaxy #Peculiar galaxy #Physics #Stellar, planetary, and galactic studies #Virial theorem #astro-ph
paper · pdf · doi:10.1086/507172
published as Astrophys.J.650:763-769,2006 · ApJ in press
arxiv created 2006/06/23 · openalex publication_date 2006/10/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
(abridged) There are good observational reasons to believe that the progenitors of red galaxies have undergone starbursts, followed by a post-starburst phase. We investigate the environments of post-starburst galaxies by measuring \(1)~number densities in 8 ,h-1~\Mpc radius comoving spheres, \(2)~transverse distances to nearest Virgo-like galaxy clusters, and \(3)~transverse distances to nearest luminous-galaxy neighbors. We compare the post-starburst galaxies to currently star-forming galaxies identified solely by A-star excess or Halpha emission. We find that post-starburst galaxies are in the same kinds of environments as star-forming galaxies; this is our ``null hypothesis''. More importantly, we find that at each value of the A-star excess, the star-forming and post-starburst galaxies lie in very similar distributions of environment. The only deviations from our null hypothesis are barely significant: a slight deficit of post-starburst galaxies (relative to the star-forming population) in very low-density regions, a small excess inside the virial radii of clusters, and a slight excess with nearby neighbors. None of these effects is strong enough to make the post-starburst galaxies a high-density phenomenon, or to argue that the starburst events are primarily triggered by external tidal impulses ( eg, from close passages of massive galaxies). The small excess inside cluster virial radii suggests that some post-starbursts are triggered by interactions with the intracluster medium, but this represents a very small fraction of all post-starburst galaxies.