ALMA 26 Arcmin2 Survey of GOODS-S at One Millimeter (ASAGAO): Average Morphology of High-z Dusty Star-forming Galaxies in an Exponential Disk (n ≃ 1)

Seiji Fujimoto, Masami Ouchi, Kotaro Kohno, Yuki Yamaguchi, Bunyo Hatsukade, Yoshihiro Ueda, Takatoshi Shibuya, Shigeki Inoue, Taira Oogi, Sune Toft, Carlos Gómez-Guijarro, Tao Wang, Daniel Espada, Tohru Nagao, Ichi Tanaka, Yiping Ao, Hideki Umehata, Yoshiaki Taniguchi, Kouichiro Nakanishi, Wiphu RujopakarnR. J. Ivison, Wei Hao Wang, Minju M. Lee, Ken Ichi Tadaki, Yoichi Tamura, J. S. Dunlop

Research output: Contribution to journalArticlepeer-review

Abstract

We present morphological properties of dusty star-forming galaxies at z = 1-3 determined with the high-resolution (FWHM ∼ 0.″19) Atacama Large Milllimeter/submillimeter Array (ALMA) 1 mm map of our ASAGAO survey covering a 26 arcmin2 area in GOODS-S. In conjunction with the ALMA archival data, our sample consists of 45 ALMA sources with infrared luminosity (L IR) range of ∼1011-1013 L o. To obtain an average rest-frame far-infrared (FIR) profile, we perform individual measurements and careful stacking of the ALMA sources using the uv-visibility method that includes positional-uncertainty and smoothing-effect evaluations through Monte Carlo simulations. We find that our sample has an average FIR-wavelength Sérsic index and effective radius of n FIR = 1.2 ± 0.2 and R e,FIR = 1.0-1.3 kpc, respectively, additionally with a point-source component at the center, indicative of the existence of active galactic nuclei. The average FIR profile agrees with a morphology of an exponential disk clearly distinguished from a de Vaucouleurs spheroidal profile (Sérsic index of 4). We also examine the rest-frame optical Sérsic index n opt and effective radius R e,opt with deep Hubble Space Telescope (HST) images. Interestingly, we obtain n opt = 0.9 ± 0.3 (≃n FIR) and R e,opt = 3.2 ± 0.6 kpc (>R e,FIR), suggesting that the dusty disk-like structure is embedded within a larger stellar disk. The rest-frame UV and FIR data of HST and ALMA provide us with a radial profile of the total star formation rate (SFR), where the infrared SFR dominates over the UV SFR at the center. Under the assumption of a constant SFR, a compact stellar distribution in z ∼ 1-2 compact quiescent galaxies (cQGs) is well reproduced, while a spheroidal stellar morphology of cQGs (n opt = 4) is not, suggestive of other important mechanism(s) such as dynamical dissipation.

Original languageEnglish
Article number7
JournalAstrophysical Journal
Volume861
Issue number1
DOIs
Publication statusPublished - 26 Jun 2018

Keywords

  • galaxies: evolution
  • galaxies: formation
  • galaxies: high-redshift
  • galaxies: star formation
  • galaxies: starburst

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