Morphologies of ∼190,000 galaxies at z = 0–10 revealed with HST legacy data. II. Evolution of clumpy galaxies

Journal Article · Wed Apr 20 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/821/2/72· OSTI ID:22890064

Shibuya, Takatoshi; Ouchi, Masami; Kubo, Mariko; Harikane, Yuichi ^[1]

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1. Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan)

We investigate the evolution of clumpy galaxies with Hubble Space Telescope (HST) samples of ∼17,000 photo-z and Lyman break galaxies at z ≃ 0–8. We detect clumpy galaxies with off-center clumps in a self-consistent algorithm that is well tested with previous study results, and we measure the number fraction of clumpy galaxies at the rest-frame UV, f{sub clumpy}{sup UV}. We identify an evolutionary trend of f{sub clumpy}{sup UV} over z ≃ 0–8 for the first time: f{sub clumpy}{sup UV} increases from z ≃ 8 to z ≃ 1–3 and subsequently decreases from z ≃ 1 to z ≃ 0, which follows the trend of the Madau–Lilly plot. A low average Sérsic index of n ≃ 1 is found in the underlining components of our clumpy galaxies at z ≃ 0–2, indicating that typical clumpy galaxies have disk-like surface brightness profiles. Our f{sub clumpy}{sup UV} values correlate with physical quantities related to star formation activities for star-forming galaxies at z ≃ 0–7. We find that clump colors tend to be red at a small galactocentric distance for massive galaxies with logM{sub ∗}/M{sub ⊙} ≳ 11. All of these results are consistent with the picture that a majority of clumps form in the violent disk instability and migrate into the galactic centers.

• OSTI ID: 22890064
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 821; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALGORITHMS
BRIGHTNESS
COSMOLOGY
DISTANCE
GALACTIC EVOLUTION
GALAXIES
GALAXY NUCLEI
RED SHIFT
SPACE
STARS
SURFACES
TELESCOPES
UNIVERSE