{
  "id": "2310.07498",
  "version": "v1",
  "published": "2023-10-11T13:52:26.000Z",
  "updated": "2023-10-11T13:52:26.000Z",
  "title": "Low-mass Quiescent Galaxies Are Small in Isolated Environments: Environmental Dependence of the Mass-Size Relation of Low-mass Quiescent Galaxies",
  "authors": [
    "Yongmin Yoon",
    "Jae-Woo Kim",
    "Jongwan Ko"
  ],
  "comment": "20 pages, 14 figures, 1 table, accepted for publication in the ApJ",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We study the mass-size relation of quiescent galaxies across various environments, with a particular focus on its environmental dependence at the low-mass part of $\\log(M_\\mathrm{star}/M_{\\odot})\\lesssim10.0$. Our sample consists of 13,667 quiescent galaxies with $\\log(M_\\mathrm{star}/M_{\\odot})\\ge9.4$ and $0.01<z<0.04$ from the Sloan Digital Sky Survey. We find that the mass-size relation of low-mass quiescent galaxies (LQGs) with $\\log(M_\\mathrm{star}/M_{\\odot})\\lesssim10.0$ depends on their environment, with LQGs in the highest-density environments exhibiting an average size $\\sim70\\%$ larger than those in isolated environments. Moreover, the slope of the mass-size relation for LQGs in high-density environments is significantly shallower than that of their counterparts in isolated environments. This is in contrast with high-mass quiescent galaxies with $\\log(M_\\mathrm{star}/M_{\\odot})\\gtrsim10.5$ that show a nearly identical mass-size relation across all environments. Combined with additional discoveries that the mass-size relation slopes of LQGs and star-forming galaxies are similar to each other in high-density environments, and that LQGs in higher-density environments exhibit more disk-like structures, our results support the idea that LQGs in high-density environments have evolved from star-forming galaxies through environmental effects, which are capable of causing their quenching and transformation into quiescent galaxies. With the aid of an analysis of merger rates for simulated galaxies from a cosmological galaxy formation simulation, we suggest that the steep slope and low normalization of the mass-size relation of LQGs in the lowest-density environments may originate from recent gas-rich mergers, which occur over 10-30 times more frequently in the progenitors of LQGs in the lowest-density environments than in their counterparts in high-density environments at low redshifts.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-10-11T13:52:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "low-mass quiescent galaxies",
      "mass-size relation",
      "isolated environments",
      "environmental dependence",
      "high-density environments"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 20,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}