Bulge-forming galaxies with an extended rotating disk at z~2
| Autor: | Tadaki, Ken-ichi, Genzel, Reinhard, Kodama, Tadayuki, Wuyts, Stijn, Wisnioski, Emily, Schreiber, Natascha M. Förster, Burkert, Andreas, Lang, Philipp, Tacconi, Linda J., Lutz, Dieter, Belli, Sirio, Davies, Richard I., Hatsukade, Bunyo, Hayashi, Masao, Herrera-Camus, Rodrigo, Ikarashi, Soh, Inoue, Shigeki, Kohno, Kotaro, Koyama, Yusei, Mendel, J. Trevor, Nakanishi, Kouichiro, Shimakawa, Rhythm, Suzuki, Tomoko L., Tamura, Yoichi, Tanaka, Ichi, Übler, Hannah, Wilman, Dave J. |
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| Rok vydání: | 2016 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/834/2/135 |
| Popis: | We present 0".2-resolution Atacama Large Millimeter/submillimeter Array observations at 870 um for 25 Halpha-seleced star-forming galaxies (SFGs) around the main-sequence at z=2.2-2.5. We detect significant 870 um continuum emission in 16 (64%) of these SFGs. The high-resolution maps reveal that the dust emission is mostly radiated from a single region close to the galaxy center. Exploiting the visibility data taken over a wide $uv$ distance range, we measure the half-light radii of the rest-frame far-infrared emission for the best sample of 12 massive galaxies with logM*>11. We find nine galaxies to be associated with extremely compact dust emission with R_{1/2,870um}<1.5 kpc, which is more than a factor of 2 smaller than their rest-optical sizes, R_{1/2,1.6um}=3.2 kpc, and is comparable with optical sizes of massive quiescent galaxies at similar redshifts. As they have an exponential disk with Sersic index of n=1.2 in the rest-optical, they are likely to be in the transition phase from extended disks to compact spheroids. Given their high star formation rate surface densities within the central 1 kpc of Sigma SFR1kpc=40 Msol/yr/kpc^2, the intense circumnuclear starbursts can rapidly build up a central bulge with Sigma M*1kpc>1e10 Msol/kpc^2 in several hundred Myr, i.e. by z~2. Moreover, ionized gas kinematics reveal that they are rotation-supported with an angular momentum as large as that of typical SFGs at z=1-3. Our results suggest bulges are commonly formed in extended rotating disks by internal processes, not involving major mergers. Comment: 11 pages, 6 figures, 2 tables, accepted for publication in ApJ |
| Databáze: | arXiv |
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