Physical properties of spectroscopically confirmed galaxies at z ≥ 6. II. Morphology of the rest-frame UV continuum and Lyα emission

Linhua Jiang, Eiichi Egami, Xiaohui Fan, Rogier Windhorst, Seth H. Cohen, Romeel Davé, Kristian Finlator, Nobunari Kashikawa, Matthew Mechtley, Masami Ouchi, Kazuhiro Shimasaku

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

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 Lyα emitters (LAEs) at z ≃ 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 1500 ≤ -20.5 mag. The intrinsic half-light radii r hl, in, after correcting for point-spread function (PSF) broadening, are roughly between r hl, in ≃ 0.″05 (0.3 kpc) and 0.″3 (1.7 kpc) at M 1500 ≤ -19.5 mag. The median r hl, in value is 0.″16 (∼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 hl, in∝L 0.14 at M 1500 ≤ -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples. We discuss the morphology of z ≥ 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M 20 parameters, and demonstrate their validity through simulations. We search for extended Lyα emission halos around LAEs at z ≃ 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Lyα 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 Lyα 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.

Original languageEnglish (US)
Article number153
JournalAstrophysical Journal
Volume773
Issue number2
DOIs
StatePublished - Aug 20 2013

Fingerprint

physical property
physical properties
galaxies
continuums
halos
stacking
simulation
Hubble Space Telescope
asymmetry
narrowband
interacting galaxies
point spread functions
misalignment
emitters
luminosity
telescopes
slopes
broadband
radii

Keywords

  • cosmology: observations
  • galaxies: evolution
  • galaxies: high-redshift

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Physical properties of spectroscopically confirmed galaxies at z ≥ 6. II. Morphology of the rest-frame UV continuum and Lyα emission. / Jiang, Linhua; Egami, Eiichi; Fan, Xiaohui; Windhorst, Rogier; Cohen, Seth H.; Davé, Romeel; Finlator, Kristian; Kashikawa, Nobunari; Mechtley, Matthew; Ouchi, Masami; Shimasaku, Kazuhiro.

In: Astrophysical Journal, Vol. 773, No. 2, 153, 20.08.2013.

Research output: Contribution to journalArticle

Jiang, L, Egami, E, Fan, X, Windhorst, R, Cohen, SH, Davé, R, Finlator, K, Kashikawa, N, Mechtley, M, Ouchi, M & Shimasaku, K 2013, 'Physical properties of spectroscopically confirmed galaxies at z ≥ 6. II. Morphology of the rest-frame UV continuum and Lyα emission', Astrophysical Journal, vol. 773, no. 2, 153. https://doi.org/10.1088/0004-637X/773/2/153
Jiang, Linhua ; Egami, Eiichi ; Fan, Xiaohui ; Windhorst, Rogier ; Cohen, Seth H. ; Davé, Romeel ; Finlator, Kristian ; Kashikawa, Nobunari ; Mechtley, Matthew ; Ouchi, Masami ; Shimasaku, Kazuhiro. / Physical properties of spectroscopically confirmed galaxies at z ≥ 6. II. Morphology of the rest-frame UV continuum and Lyα emission. In: Astrophysical Journal. 2013 ; Vol. 773, No. 2.
@article{b93d0a06954b41ec8dc59cdbffe18758,
title = "Physical properties of spectroscopically confirmed galaxies at z ≥ 6. II. Morphology of the rest-frame UV continuum and Lyα emission",
abstract = "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 Lyα emitters (LAEs) at z ≃ 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 1500 ≤ -20.5 mag. The intrinsic half-light radii r hl, in, after correcting for point-spread function (PSF) broadening, are roughly between r hl, in ≃ 0.″05 (0.3 kpc) and 0.″3 (1.7 kpc) at M 1500 ≤ -19.5 mag. The median r hl, in value is 0.″16 (∼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 hl, in∝L 0.14 at M 1500 ≤ -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples. We discuss the morphology of z ≥ 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M 20 parameters, and demonstrate their validity through simulations. We search for extended Lyα emission halos around LAEs at z ≃ 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Lyα 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 Lyα 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.",
keywords = "cosmology: observations, galaxies: evolution, galaxies: high-redshift",
author = "Linhua Jiang and Eiichi Egami and Xiaohui Fan and Rogier Windhorst and Cohen, {Seth H.} and Romeel Dav{\'e} and Kristian Finlator and Nobunari Kashikawa and Matthew Mechtley and Masami Ouchi and Kazuhiro Shimasaku",
year = "2013",
month = "8",
day = "20",
doi = "10.1088/0004-637X/773/2/153",
language = "English (US)",
volume = "773",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",

}

TY - JOUR

T1 - Physical properties of spectroscopically confirmed galaxies at z ≥ 6. II. Morphology of the rest-frame UV continuum and Lyα emission

AU - Jiang, Linhua

AU - Egami, Eiichi

AU - Fan, Xiaohui

AU - Windhorst, Rogier

AU - Cohen, Seth H.

AU - Davé, Romeel

AU - Finlator, Kristian

AU - Kashikawa, Nobunari

AU - Mechtley, Matthew

AU - Ouchi, Masami

AU - Shimasaku, Kazuhiro

PY - 2013/8/20

Y1 - 2013/8/20

N2 - 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 Lyα emitters (LAEs) at z ≃ 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 1500 ≤ -20.5 mag. The intrinsic half-light radii r hl, in, after correcting for point-spread function (PSF) broadening, are roughly between r hl, in ≃ 0.″05 (0.3 kpc) and 0.″3 (1.7 kpc) at M 1500 ≤ -19.5 mag. The median r hl, in value is 0.″16 (∼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 hl, in∝L 0.14 at M 1500 ≤ -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples. We discuss the morphology of z ≥ 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M 20 parameters, and demonstrate their validity through simulations. We search for extended Lyα emission halos around LAEs at z ≃ 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Lyα 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 Lyα 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.

AB - 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 Lyα emitters (LAEs) at z ≃ 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 1500 ≤ -20.5 mag. The intrinsic half-light radii r hl, in, after correcting for point-spread function (PSF) broadening, are roughly between r hl, in ≃ 0.″05 (0.3 kpc) and 0.″3 (1.7 kpc) at M 1500 ≤ -19.5 mag. The median r hl, in value is 0.″16 (∼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 hl, in∝L 0.14 at M 1500 ≤ -19.5 mag. The slope of 0.14 is significantly flatter than those in fainter LBG samples. We discuss the morphology of z ≥ 6 galaxies with nonparametric methods, including the concentration, asymmetry, and smoothness system and the Gini and M 20 parameters, and demonstrate their validity through simulations. We search for extended Lyα emission halos around LAEs at z ≃ 5.7 and 6.5 by stacking a number of narrow-band images. We do not find evidence of extended Lyα 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 Lyα 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.

KW - cosmology: observations

KW - galaxies: evolution

KW - galaxies: high-redshift

UR - http://www.scopus.com/inward/record.url?scp=84881448892&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84881448892&partnerID=8YFLogxK

U2 - 10.1088/0004-637X/773/2/153

DO - 10.1088/0004-637X/773/2/153

M3 - Article

VL - 773

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 153

ER -