The Environmental Dependence of the Mass-Size Relation in the Most Massive Galaxies

  • Yoon, Yongmin (CEOU/Astronomy Program, Dept. of Physics & Astronomy, Seoul National University) ;
  • Im, Myungshin (CEOU/Astronomy Program, Dept. of Physics & Astronomy, Seoul National University)
  • 발행 : 2015.04.10

초록

We study the environmental dependence of the mass-size relation especially for the most massive early type galaxies (M>$10^{11.2}M_{\odot}$) in the redshift range 0.15~0.25. As a measure of the environment, galaxy number densities are measured by the $10^{th}$ nearest galaxies within 7000km/s from galaxies with spectroscopic redshifts. We find that galaxies more massive than $10^{11.6}M_{\odot}$ show the environmental dependence in the mass-size relation. The galaxies with M>$10^{11.6}M_{\odot}$ located in the densest, cluster like environment have larger sizes than their counterparts located in a low dense environment. We also find that this environmental dependence of the mass-size relation originates from the brightest cluster galaxies (BCG) rather than non-BCG galaxies. Our result can be explained with a hierarchical growth of the most massive galaxies through dissipation-less merger in dense environments.

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