Morphologies of ∼190,000 galaxies at z = 0–10 revealed with HST legacy data. I. size evolution
- Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)
We present the redshift evolution of the galaxy effective radius r{sub e} obtained from the Hubble Space Telescope (HST) samples of ∼190,000 galaxies at z = 0–10. Our HST samples consist of 176,152 photo-z galaxies at z = 0–6 from the 3D-HST+CANDELS catalog and 10,454 Lyman break galaxies (LBGs) at z = 4–10 identified in the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), HUDF 09/12, and HFF parallel fields, providing the largest data set to date for galaxy size evolution studies. We derive r{sub e} with the same technique over the wide redshift range of z = 0–10, evaluating the optical-to-UV morphological K correction and the selection bias of photo-z galaxies+LBGs as well as the cosmological surface-brightness dimming effect. We find that r{sub e} values at a given luminosity significantly decrease toward high z, regardless of statistics choices (e.g., r{sub e}∝(1+z){sup −1.10±0.06} for median). For star-forming galaxies, there is no evolution of the power-law slope of the size–luminosity relation and the median Sérsic index (n∼1.5). Moreover, the r{sub e} distribution is well represented by log-normal functions whose standard deviation σ{sub lnr{sub e}} does not show significant evolution within the range of σ{sub lnr{sub e}}∼0.45−0.75. We calculate the stellar-to-halo size ratio from our r{sub e} measurements and the dark-matter halo masses estimated from the abundance-matching study, and we obtain a nearly constant value of r{sub e}/r{sub vir}=1.0%−3.5% at z = 0–8. The combination of the r{sub e}-distribution shape+standard deviation, the constant r{sub e}/r{sub vir}, and n∼1.5 suggests a picture in which typical high-z star-forming galaxies have disk-like stellar components in a sense of dynamics and morphology over cosmic time of z∼0−6. If high-z star-forming galaxies are truly dominated by disks, the r{sub e}/r{sub vir} value and the disk-formation model indicate that the specific angular momentum of the disk normalized by the host halo is j{sub d}/m{sub d}≃0.5−1. These are statistical results for major stellar components of galaxies, and the detailed study of clumpy subcomponents is presented in the paper II.
- OSTI ID:
- 22872434
- Journal Information:
- Astrophysical Journal, Supplement Series, Vol. 219, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0067-0049
- Country of Publication:
- United States
- Language:
- English
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