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Title: PHYSICAL PROPERTIES OF SPECTROSCOPICALLY CONFIRMED GALAXIES AT z {>=} 6. II. MORPHOLOGY OF THE REST-FRAME UV CONTINUUM AND Ly{alpha} EMISSION

We present a detailed structural and morphological study of a large sample of spectroscopically confirmed galaxies at z {>=} 6 using deep Hubble Space Telescope (HST) near-IR broad-band images and Subaru Telescope optical narrow-band images. The galaxy sample consists of 51 Ly{alpha} emitters (LAEs) at z {approx_equal} 5.7, 6.5, and 7.0, and 16 Lyman break galaxies (LBGs) at 5.9 {<=} z {<=} 6.5. These galaxies exhibit a wide range of rest-frame UV continuum morphology in the HST images, from compact features to multiple component systems. The fraction of merging/interacting galaxies reaches 40%-50% at the brightest end of M{sub 1500} {<=} -20.5 mag. The intrinsic half-light radii r{sub hl,in}, after correcting for point-spread function (PSF) broadening, are roughly between r{sub hl,in} {approx_equal} 0.''05 (0.3 kpc) and 0.''3 (1.7 kpc) at M{sub 1500} {<=} -19.5 mag. The median r{sub hl,in} value is 0.''16 ({approx}0.9 kpc). This is consistent with the sizes of bright LAEs and LBGs at z {>=} 6 found in previous studies. In addition, more luminous galaxies tend to be larger and exhibit a weak size-luminosity relation, r{sub hl,in}{proportional_to}L {sup 0.14} at M{sub 1500} {<=} -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples.more » We discuss the morphology of z {>=} 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M{sub 20} parameters, and demonstrate their validity through simulations. We search for extended Ly{alpha} emission halos around LAEs at z {approx_equal} 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Ly{alpha} halos predicted by cosmological simulations. Such halos, if they exist, could be weaker than predicted. Finally, we investigate positional misalignment between the UV continuum and Ly{alpha} emissions in LAEs. While the two positions are generally consistent, several merging galaxies show significant positional differences. This is likely caused by a disturbed interstellar medium distribution due to merging activity.« less
Authors:
; ; ;  [1] ; ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1504 (United States)
  2. Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
  3. Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen O (Denmark)
  4. Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan)
  5. Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)
  6. Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033 (Japan)
Publication Date:
OSTI Identifier:
22130974
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; CONCENTRATION RATIO; EMISSION; GALACTIC EVOLUTION; GALAXIES; IMAGES; LUMINOSITY; LYMAN LINES; MORPHOLOGY; PHYSICAL PROPERTIES; RED SHIFT; SIMULATION; TELESCOPES; ULTRAVIOLET RADIATION