SXDF-ALMA 1.5 arcmin2 deep survey: A compact dusty star-forming galaxy at z = 2.5

Ken Ichi Tadaki, Kotaro Kohno, Tadayuki Kodama, Soh Ikarashi, Itziar Aretxaga, Stefano Berta, Karina I. Caputi, James S. Dunlop, Bunyo Hatsukade, Masao Hayashi, David H. Hughes, Rob Ivison, Takuma Izumi, Yusei Koyama, Dieter Lutz, Ryu Makiya, Yuichi Matsuda, Kouichiro Nakanishi, Wiphu Rujopakarn, Yoichi TamuraHideki Umehata, Wei Hao Wang, Grant W. Wilson, Stijn Wuyts, Yuki Yamaguchi, Min S. Yun

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39 Citations (Scopus)


We present the first results from the SXDF-Atacama Large Millimeter/submillimeter Array (ALMA) 1.5 arcmin2 deep survey at 1.1 mm using ALMA. The map reaches a 1σ depth of 55 μJy/beam and covers 12 Hα-selected star-forming galaxies (SFGs) at z = 2.19 or z = 2.53. We have detected continuum emission from three of our Hα-selected sample, including one compact SFG with high stellar surface density, NB2315-07. They are all red in the rest-frame optical and have stellar masses of log (M/Mo) > 10.9, whereas the other blue, main-sequence galaxies with = 10.0-10.8 are exceedingly faint, <290 μJy (2σ upper limit). We also find the 1.1 mm brightest galaxy, NB2315-02, to be associated with a compact (Re = 0.7 ± 0.1 kpc), dusty star-forming component. Given a high gas fraction (44+20-8% or 37+25-3%) and high star formation rate surface density (126+27-30 yr-1 kpc-2), the concentrated starburst can build up within less than 50+22-11Myr a stellar surface density matching that of massive compact galaxies at z ∼ 2, provided at least 19 ± 3% of the total gas is converted into stars in the galaxy center. On the other hand, NB2315-07, which already has such a high stellar surface density core, shows a gas fraction (23+8-8%) and is located in the lower envelope of the star formation main sequence. This compact, less SFG is likely to be in an intermediate phase between compact, dusty star-forming and quiescent galaxies.

Original languageEnglish
Article numberL3
JournalAstrophysical Journal Letters
Issue number1
Publication statusPublished - 2015 Sept 20


  • galaxies: ISM
  • galaxies: evolution
  • galaxies: high-redshift


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