論文 - 田村　陽一

ALMA Deep Field in SSA22: Source Catalog and Number Counts 査読有り 国際誌 Open Access

Hideki Umehata, Yoichi Tamura, Kotaro Kohno, R. J. Ivison, Ian Smail, Bunyo Hatsukade, Kouichiro Nakanishi, Yuta Kato, Soh Ikarashi, Yuichi Matsuda, Seiji Fujimoto, Daisuke Iono, Minju Lee, Charles C. Steidel, Tomoki Saito, D. M. Alexander, Min S. Yun, Mariko Kubo

The Astrophysical Journal   835 巻 ( 1 ) 頁： 98 - 98   2017年1月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Astronomical Society  

<jats:title>Abstract</jats:title>
<jats:p>We present results from a deep 2′ × 3′ (comoving scale of 3.7 Mpc × 5.5 Mpc at <jats:italic>z</jats:italic> = 3) survey at 1.1 mm, taken with the Atacama Large Millimeter/submillimeter Array (ALMA) in the SSA22 field. We observe the core region of a <jats:italic>z</jats:italic> = 3.09 protocluster, achieving a typical rms sensitivity of 60 <jats:italic>μ</jats:italic>Jy beam<jats:sup>−1</jats:sup> at a spatial resolution of 0.″7. We detect 18 robust ALMA sources at a signal-to-noise ratio (S/N) > 5. Comparison between the ALMA map and a 1.1 mm map, taken with the AzTEC camera on the Atacama Submillimeter Telescope Experiment (ASTE), indicates that three submillimeter sources discovered by the AzTEC/ASTE survey are resolved into eight individual submillimeter galaxies (SMGs) by ALMA. At least 10 of our 18 ALMA SMGs have spectroscopic redshifts of <jats:italic>z</jats:italic> ≃ 3.09, placing them in the protocluster. This shows that a number of dusty starburst galaxies are forming simultaneously in the core of the protocluster. The nine brightest ALMA SMGs with S/N > 10 have a median intrinsic angular size of <jats:inline-formula>
<jats:tex-math>
<?CDATA $0\buildrel{\prime\prime}\over{.} {32}_{-0.06}^{+0.13}$?>
</jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa5107ieqn1.gif" xlink:type="simple" />
</jats:inline-formula> (<jats:inline-formula>
<jats:tex-math>
<?CDATA ${2.4}_{-0.4}^{+1.0}$?>
</jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa5107ieqn2.gif" xlink:type="simple" />
</jats:inline-formula> physical kpc at <jats:italic>z</jats:italic> = 3.09), which is consistent with previous size measurements of SMGs in other fields. As expected, the source counts show a possible excess compared to the counts in the general fields at <jats:italic>S</jats:italic>
<jats:sub>1.1mm</jats:sub> ≥ 1.0 mJy, due to the protocluster. Our contiguous mm mapping highlights the importance of large-scale structures on the formation of dusty starburst galaxies.</jats:p>

DOI： 10.3847/1538-4357/835/1/98

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arXiv

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ALMA Reveals Strong [C II] Emission in a Galaxy Embedded in a Giant Ly α Blob at z = 3.1 査読有り 国際誌

Hideki Umehata, Yuichi Matsuda, Yoichi Tamura, Kotaro Kohno, Ian Smail, R. J. Ivison, Charles C. Steidel, Scott C. Chapman, James E. Geach, Matthew Hayes, Tohru Nagao, Yiping Ao, Ryohei Kawabe, Min S. Yun, Bunyo Hatsukade, Mariko Kubo, Yuta Kato, Tomoki Saito, Soh Ikarashi, Kouichiro Nakanishi, Minju Lee, Takuma Izumi, Masao Mori, Masami Ouchi

The Astrophysical Journal   834 巻 ( 2 )   2017年1月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Astronomical Society  

We report the result from observations conducted with the Atacama Large
Millimeter/submillimeter Array (ALMA) to detect [CII] 158 um fine structure
line emission from galaxies embedded in one of the most spectacular Lyman-alpha
blobs (LABs) at z=3.1, SSA22-LAB1. Of three dusty star-forming galaxies
previously discovered by ALMA 860 um dust continuum survey toward SSA22-LAB1,
we detected the [CII] line from one, LAB1-ALMA3 at z=3.0993+/-0.0004. No line
emission was detected, associated with the other ALMA continuum sources or from
three rest-frame UV/optical selected z_spec~3.1 galaxies within the field of
view. For LAB1-ALMA3, we find relatively bright [CII] emission compared to the
infrared luminosity (L_[CII]/L_[CII]) and an extremely high [CII] 158 um and
[NII] 205 um emission line ratio (L_[CII]/L_[NII]>55). The relatively strong
[CII] emission may be caused by abundant photodissociation regions and
sub-solar metallicity, or by shock heating. The origin of the unusually strong
[CII] emission could be causally related to the location within the giant LAB,
although the relationship between extended Lyman-alpha emission and ISM
conditions of associated galaxies is yet to be understand.

DOI： 10.3847/2041-8213/834/2/L16

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arXiv

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BULGE-FORMING GALAXIES WITH AN EXTENDED ROTATING DISK AT z ∼ 2 査読有り 国際誌 Open Access

Ken-ichi Tadaki, Reinhard Genzel, Tadayuki Kodama, Stijn Wuyts, Emily Wisnioski, Natascha M. Förster Schreiber, Andreas Burkert, Philipp Lang, Linda J. Tacconi, Dieter Lutz, Sirio Belli, Richard I. Davies, Bunyo Hatsukade, Masao Hayashi, Rodrigo Herrera-Camus, Soh Ikarashi, Shigeki Inoue, Kotaro Kohno, Yusei Koyama, J. Trevor Mendel, Kouichiro Nakanishi, Rhythm Shimakawa, Tomoko L. Suzuki, Yoichi Tamura, Ichi Tanaka, Hannah Übler, Dave J. Wilman

The Astrophysical Journal   834 巻 ( 2 ) 頁： 135   2017年1月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Astronomical Society  

<jats:title>ABSTRACT</jats:title>
<jats:p>We present 0.″2-resolution Atacama Large Millimeter/submillimeter Array observations at 870 <jats:italic>μ</jats:italic>m for 25 H<jats:italic>α</jats:italic>-seleced star-forming galaxies around the main sequence at <jats:italic>z</jats:italic> = 2.2–2.5. We detect significant 870 <jats:italic>μ</jats:italic>m continuum emission in 16 (64%) of these galaxies. 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 <jats:italic>uv</jats:italic> distance range, we measure the half-light radii of the rest-frame far-infrared emission for the best sample of 12 massive galaxies with log(<jats:italic>M</jats:italic>
<jats:sub>*</jats:sub>/<jats:italic>M</jats:italic>
<jats:sub>⊙</jats:sub>) > 11. We find nine galaxies to be associated with extremely compact dust emission with <jats:italic>R</jats:italic>
<jats:sub>1/2,870 <jats:italic>μ</jats:italic>m</jats:sub> < 1.5 kpc, which is more than a factor of 2 smaller than their rest-optical sizes, <jats:inline-formula>
<jats:tex-math>
<?CDATA $\langle {R}_{1/2,1.6\mu {\rm{m}}}\rangle =3.2\,\mathrm{kpc}$?>
</jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa499bieqn1.gif" xlink:type="simple" />
</jats:inline-formula>, and is comparable with optical sizes of massive quiescent galaxies at similar redshifts. As they have an exponential disk with Sérsic index of <jats:inline-formula>
<jats:tex-math>
<?CDATA $\langle {n}_{1.6\mu {\rm{m}}}\rangle =1.2$?>
</jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa499bieqn2.gif" xlink:type="simple" />
</jats:inline-formula> 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 <jats:inline-formula>
<jats:tex-math>
<?CDATA $\langle {\rm{\Sigma }}{\mathrm{SFR}}_{1\mathrm{kpc}}\rangle =40$?>
</jats:tex-math>
<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="apjaa499bieqn3.gif" xlink:type="simple" />
</jats:inline-formula>
<jats:italic>M</jats:italic>
<jats:sub>⊙</jats:sub> yr<jats:sup>−1</jats:sup> kpc<jats:sup>−2</jats:sup>, the intense circumnuclear starbursts can rapidly build up a central bulge with Σ<jats:italic>M</jats:italic>
<jats:sub>*,1 kpc</jats:sub> > 10<jats:sup>10</jats:sup>
<jats:italic>M</jats:italic>
<jats:sub>⊙</jats:sub> kpc<jats:sup>−2</jats:sup> in several hundred megayears, i.e., by <jats:italic>z</jats:italic> ∼ 2. Moreover, ionized gas kinematics reveal that they are rotation supported with an angular momentum as large as that of typical star-forming galaxies at <jats:italic>z</jats:italic> = 1–3. Our results suggest that bulges are commonly formed in extended rotating disks by internal processes, not involving major mergers.</jats:p>

DOI： 10.3847/1538-4357/834/2/135

Web of Science

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arXiv

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