{
  "id": "2104.08282",
  "version": "v1",
  "published": "2021-04-16T18:00:01.000Z",
  "updated": "2021-04-16T18:00:01.000Z",
  "title": "The Compact UV Size of Green Pea Galaxies As Local Analogs of High Redshift Ly$α$-Emitters",
  "authors": [
    "Keunho J. Kim",
    "Sangeeta Malhotra",
    "James E. Rhoads",
    "Huan Yang"
  ],
  "comment": "10 pages. Main results are Figure 4 and Table 2, accepted by ApJ",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We study the dependence of Ly$\\alpha$ escape from galaxies on UV continuum size and luminosity using a sample of 40 Green Pea (GP) galaxies, which are the best local analogs of high-redshift Ly$\\alpha$-emitters (LAEs). We use the Cosmic Origins Spectrograph near-ultraviolet images from the \\textit{Hubble Space Telescope} to measure the UV size and luminosity with $0.047''$ spatial resolution. Like most galaxies the GPs show a log-normal size distribution. They also show a positive correlation between size and UV-continuum luminosity. The slope of the size-continuum luminosity relation for GPs is consistent with those of continuum-selected star-forming galaxies at low and high redshifts. A distinctive feature of GPs is a very compact typical radius of 0.33 kpc with a population spread (1$\\sigma$) of 0.19 kpc. The peak of the size distribution and the intercept of the size-luminosity relation of GPs are noticeably smaller than those of continuum-selected star-forming galaxies at similar redshifts. There are statistically significant anti-correlations found between the circularized half-light radius ($r_{\\rm cir,50}$), the Ly$\\alpha$ equivalent width (EW(Ly$\\alpha$)), and the Ly$\\alpha$ escape faction ($f^{Ly\\alpha}_{esc}$), suggesting that small UV-continuum radii are crucial for Ly$\\alpha$ emission. GPs and high-redshift LAEs have similar sizes, once spatial resolution effects are properly considered. Our results show that a compact/small size is crucial for escape of Ly$\\alpha$ photons, and that Ly$\\alpha$-emitters show constant characteristic size independent of their redshift.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-04-16T18:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "green pea galaxies",
      "local analogs",
      "high redshift ly",
      "compact uv size",
      "cosmic origins spectrograph near-ultraviolet images"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}