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Title: The nature of Hα-selected galaxies at z > 2. II. Clumpy galaxies and compact star-forming galaxies

We present the morphological properties of Hα-selected galaxies at z > 2 in SXDF-UDS-CANDELS field. With high-resolution optical/near-infrared images obtained by the Hubble Space Telescope, we identify giant clumps within the Hα emitters (HAEs). We find that at least 41% of our sample shows clumpy structures in the underlying disks. The color gradient of clumps is commonly seen in the sense that the clumps near the galactic center tend to be redder than those in the outer regions. The mid-infrared detection in galaxies with red clumps and the spatial distribution of Hα emission suggest that dusty star-formation activity is probably occurring in the nuclear red clumps. A gas supply to a bulge component through clump migration is one of the most potent physical processes for producing such dusty star-forming clumps and forming massive bulges in local early-type galaxies. They would become large quiescent galaxies at later times just by consumption or blowout of remaining gas. Also, while most of the HAEs have extended disks, we observe two massive, compact HAEs whose stellar surface densities are significantly higher. They are likely to be the direct progenitors of massive, compact quiescent galaxies at z = 1.5-2.0. Two evolutionary paths to massive quiescentmore » galaxies are devised to account for both the size growth of quiescent galaxies and their increased number density from z ∼ 2 to z = 0.« less
Authors:
; ;  [1] ;  [2] ;  [3] ;  [4]
  1. Optical and Infrared Astronomy Division, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)
  2. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
  3. Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)
  4. Department of Astronomical Science, The Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588 (Japan)
Publication Date:
OSTI Identifier:
22348292
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLOWOUTS; COLOR; DENSITY; DETECTION; EMISSION; EVOLUTION; GALAXIES; RED SHIFT; RESOLUTION; SPACE; SPATIAL DISTRIBUTION; STAR EVOLUTION; STARS; SURFACES; TELESCOPES