Faculty Profiles - TAMURA Yoichi

Papers - TAMURA Yoichi

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ALMA Deep Field in SSA22: Source Catalog and Number Counts Reviewed International journal 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 Vol. 835 ( 1 ) page： 98 - 98 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：American Astronomical Society

We present results from a deep 2'x3' (comoving scale of 3.7 Mpc x 5.5 Mpc at
z=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 z = 3.09
protocluster, achieving a typical rms sensitivity of 60 micro-Jy/beam at a
spatial resolution of 0".7. We detect 18 robust ALMA sources at a
signal-to-noise ratio (SNR) > 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 ten of our 18 ALMA SMGs have spectroscopic redshifts
of z = 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 SNR > 10 have a median
intrinsic angular size of 0".32+0".13-0".06 (2.4+1.0-0.4 physical kpc at z =
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 S_1.1mm >= 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.

DOI： 10.3847/1538-4357/835/1/98

ALMA Reveals Strong [C II] Emission in a Galaxy Embedded in a Giant Ly α Blob at z = 3.1 Reviewed International journal

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 Vol. 834 ( 2 ) 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：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

Web of Science

arXiv

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Bulge-forming Galaxies with an Extended Rotating Disk at z ~ 2 Reviewed International journal Open Access

Tadaki, Ken-ichi, Genzel, Reinhard, Kodama, Tadayuki, Wuyts, Stijn, Wisnioski, Emily, Förster Schreiber, Natascha M., 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.

The Astrophysical Journal Vol. 834 ( 2 ) page： 135 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：IOP PUBLISHING LTD

We present 0.″2-resolution Atacama Large Millimeter/submillimeter Array observations at 870 μm for 25 Hα-seleced star-forming galaxies around the main sequence at z = 2.2-2.5. We detect significant 870 μm 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 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 log(M*/M☉) > 11. We find nine galaxies to be associated with extremely compact dust emission with R1/2,870 μm < 1.5 kpc, which is more than a factor of 2 smaller than their rest-optical sizes, < {R}1/2,1.6μ { { m } }> =3.2 {kpc}, and is comparable with optical sizes of massive quiescent galaxies at similar redshifts. As they have an exponential disk with Sérsic index of < {n}1.6μ { { m } }> =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 < { { Σ } }{ { SFR } }1{kpc}> =40 M☉ yr-1 kpc-2, the intense circumnuclear starbursts can rapidly build up a central bulge with ΣM*,1 kpc > 1010 M☉ kpc-2 in several hundred megayears, 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 star-forming galaxies at z = 1-3. Our results suggest that bulges are commonly formed in extended rotating disks by internal processes, not involving major mergers....

DOI： 10.3847/1538-4357/834/2/135

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