Faculty Profiles - TAMURA Yoichi

Papers - TAMURA Yoichi

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A VLA Survey of Late-time Radio Emission from Superluminous Supernovae and the Host Galaxies

Bunyo Hatsukade, Nozomu Tominaga, Tomoki Morokuma, Kana Morokuma-Matsui, Yuichi Matsuda, Yoichi Tamura, Kotaro Niinuma, Kazuhiro Motogi

The Astrophysical Journal Vol. 922 ( 1 ) 2021.11

Accurate dust temperature determination in a z = 7.13 galaxy

Tom J.L.C. Bakx, Laura Sommovigo, Stefano Carniani, Andrea Ferrara, Hollis B. Akins, Seiji Fujimoto, Masato Hagimoto, Kirsten K. Knudsen, Andrea Pallottini, Yoichi Tamura, Darach Watson

Monthly Notices of the Royal Astronomical Society: Letters Vol. 508 ( 1 ) page： L58 - L63 2021.11

Language：Japanese Publishing type：Research paper (scientific journal)

We report ALMA Band 9 continuum observations of the normal, dusty star-forming galaxy A1689-zD1 at z = 7.13, resulting in a ∼4.6 σ detection at 702 GHz. For the first time, these observations probe the far-infrared spectrum shortward of the emission peak of a galaxy in the Epoch of Reionization (EoR). Together with ancillary data from earlier works, we derive the dust temperature, Td, and mass, Md, of A1689-zD1 using both traditional modified blackbody spectral energy density fitting, and a new method that relies only on the [C ii] 158 μm line and underlying continuum data. The two methods give Td = (42+13-7, 40+13-) K, and Md} = (1.7+1.3-0.7, 2.0+1.8-1.0), ×, 107, M⊙. Band 9 observations improve the accuracy of the dust temperature (mass) estimate by ∼50 per cent (6 times). The derived temperatures confirm the reported increasing Td-redshift trend between z = 0 and 8; the dust mass is consistent with a supernova origin. Although A1689-zD1 is a normal UV-selected galaxy, our results, implying that ∼85 per cent of its star-formation rate is obscured, underline the non-negligible effects of dust in EoR galaxies.

DOI： 10.1093/mnrasl/slab104

Accurate dust temperature determination in a z = 7.13 galaxy

Bakx Tom J L C, Sommovigo Laura, Carniani Stefano, Ferrara Andrea, Akins Hollis B, Fujimoto Seiji, Hagimoto Masato, Knudsen Kirsten K, Pallottini Andrea, Tamura Yoichi, Watson Darach

Monthly Notices of the Royal Astronomical Society: Letters Vol. 508 ( 1 ) page： L58 - L63 2021.11

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

We report ALMA Band 9 continuum observations of the normal, dusty star-forming galaxy A1689-zD1 at z = 7.13, resulting in a ∼4.6 σ detection at 702 GHz. For the first time, these observations probe the far-infrared spectrum shortward of the emission peak of a galaxy in the Epoch of Reionization (EoR). Together with ancillary data from earlier works, we derive the dust temperature, Td, and mass, Md, of A1689-zD1 using both traditional modified blackbody spectral energy density fitting, and a new method that relies only on the [C ii] 158 μm line and underlying continuum data. The two methods give Td=(42^+13−7,40^+13−7⁠) K, and Md=(1.7^+1.3−0.7,2.0^+1.8−1.0)×10^7M⊙⁠. Band 9 observations improve the accuracy of the dust temperature (mass) estimate by ∼50 per cent (6 times). The derived temperatures confirm the reported increasing Td-redshift trend between z = 0 and 8; the dust mass is consistent with a supernova origin. Although A1689-zD1 is a normal UV-selected galaxy, our results, implying that ∼85 per cent of its star-formation rate is obscured, underline the non-negligible effects of dust in EoR galaxies.

ALMA observations of Lyα blob 1: Multiple major mergers and widely distributed interstellar media

Hideki Umehata, Ian Smail, Charles C. Steidel, Matthew Hayes, Douglas Scott, A. M. Swinbank, R. J. Ivison, Toru Nagao, Mariko Kubo, Kouichiro Nakanishi, Yuichi Matsuda, Soh Ikarashi, Yoichi Tamura, J. E. Geach

Astrophysical Journal Vol. 918 ( 2 ) 2021.9

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

We present observations of a giant Lyα blob (LAB) in the SSA22 protocluster at z = 3.1, SSA22-LAB1, taken with the Atacama Large Millimeter/submillimeter Array. Dust continuum, along with [C II] 158 μm and CO(4–3) line emission have been detected in LAB1, showing complex morphology and kinematics across a ∼100 kpc central region. Seven galaxies at z = 3.0987–3.1016 in the surroundings are identified in [C II] and dust continuum emission, with two of them potential companions or tidal structures associated with the most massive galaxies. Spatially resolved [C II] and infrared luminosity ratios for the widely distributed media (L[CII]/LIR ≈ 10-2-10-3) suggest that the observed extended interstellar media are likely to have originated from star formation activity and the contribution from shocked gas is probably not dominant. LAB1 is found to harbor a total molecular gas mass Mmol = (8.7 ± 2.0) × 1010 Me, concentrated in the core region of the Lyα-emitting area. While (primarily obscured) star formation activity in the LAB1 core is one of the most plausible power sources for the Lyα emission, multiple major mergers found in the core may also play a role in making LAB1 exceptionally bright and extended in Lyα as a result of cooling radiation induced by gravitational interactions.

DOI： 10.3847/1538-4357/ac1106

A Massive Quiescent Galaxy Confirmed in a Protocluster at z = 3.09

Mariko Kubo, Hideki Umehata, Yuichi Matsuda, Masaru Kajisawa, Charles C. Steidel, Toru Yamada, Ichi Tanaka, Bunyo Hatsukade, Yoichi Tamura, Kouichiro Nakanishi, Kotaro Kohno, Kianhong Lee, Keiichi Matsuda

The Astrophysical Journal Vol. 919 ( 1 ) page： 6 - 6 2021.9

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

We report a massive quiescent galaxy at zspec= -3.0922+0.008-0.004 spectroscopically confirmed at a protocluster in the SSA22 field by detecting the Balmer and Ca II absorption features with the multi-object spectrometer for infrared exploration on the Keck I telescope. This is the most distant quiescent galaxy confirmed in a protocluster to date. We fit the optical to mid-infrared photometry and spectrum simultaneously with spectral energy distribution (SED) models of parametric and nonparametric star formation histories (SFHs). Both models fit the observed SED well and confirm that this object is a massive quiescent galaxy with a stellar mass of log (M∗/M⊙=11.26+0.03-0.04 and 11.54+0.03-0.00 and a star formation rate of SFR/M⊙ yr-1 < 0.3 and = -0.01+0.03-0.01 for parametric and nonparametric models, respectively. The SFH from the former modeling is described as an instantaneous starburst whereas that of the latter modeling is longer-lived, but both models agree with a sudden quenching of the star formation at ~0.6 Gyr ago. This massive quiescent galaxy is confirmed in an extremely dense group of galaxies predicted as a progenitor of a brightest cluster galaxy formed via multiple mergers in cosmological numerical simulations. We discover three new plausible [O III]λ5007 emitters at 3.0791 ≤ zspec ≤ 3.0833 serendipitously detected around the target. Two of them just between the target and its nearest massive galaxy are possible evidence of their interactions. They suggest the future great size and stellar mass evolution of this massive quiescent galaxy via mergers.

DOI： 10.3847/1538-4357/ac0cf8

A data-scientific noise-removal method for efficient submillimeter spectroscopy with single-dish telescopes

Akio Taniguchi, Yoichi Tamura, Shiro Ikeda, Tatsuya Takekoshi, Ryohei Kawabe

Astronomical Journal Vol. 162 ( 3 ) 2021.9

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

For submillimeter spectroscopy with ground-based single-dish telescopes, removing the noise contribution from the Earth's atmosphere and the instrument is essential. For this purpose, here we propose a new method based on a data-scientific approach. The key technique is statistical matrix decomposition that automatically separates the signals of astronomical emission lines from the drift noise components in the fast-sampled (1-10 Hz) time-series spectra obtained by a position-switching (PSW) observation. Because the proposed method does not apply subtraction between two sets of noisy data (i.e., on-source and off-source spectra), it improves the observation sensitivity by a factor of 2 . It also reduces artificial signals such as baseline ripples on a spectrum, which may also help to improve the effective sensitivity. We demonstrate this improvement by using the spectroscopic data of emission lines toward a high-redshift galaxy observed with a 2 mm receiver on the 50 m Large Millimeter Telescope. Since the proposed method is carried out offline and no additional measurements are required, it offers an instant improvement on the spectra reduced so far with the conventional method. It also enables efficient deep spectroscopy driven by the future 50 m class large submillimeter single-dish telescopes, where fast PSW observations by mechanical antenna or mirror drive are difficult to achieve.

DOI： 10.3847/1538-3881/ac11f7

Physical Characterization of Serendipitously Uncovered Millimeter-wave Line-emitting Galaxies at z ∼ 2.5 behind the Local Luminous Infrared Galaxy VV 114

Shoichiro Mizukoshi, Kotaro Kohno, Fumi Egusa, Bunyo Hatsukade, Takeo Minezaki, Toshiki Saito, Yoichi Tamura, Daisuke Iono, Junko Ueda, Yuichi Matsuda, Ryohei Kawabe, Minju M. Lee, Min S. Yun, Daniel Espada

The Astrophysical Journal Vol. 917 ( 2 ) 2021.8

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

We present a detailed investigation of millimeter-wave line emitters ALMA J010748.3-173028 (ALMA-J0107a) and ALMA J010747.0-173010 (ALMA-J0107b), which were serendipitously uncovered in the background of the nearby galaxy VV 114 with spectral scan observations at λ = 2-3 mm. Via Atacama Large Millimeter/submillimeter Array (ALMA) detection of CO(4-3), CO(3-2), and [C i](1-0) lines for both sources, their spectroscopic redshifts are unambiguously determined to be z = 2.4666 0.0002 and z = 2.3100 0.0002, respectively. We obtain the apparent molecular gas masses M gas of these two line emitters from [C i] line fluxes as (11.2 3.1) 1010 M o˙ and (4.2 1.2) 1010 M o˙, respectively. The observed CO(4-3) velocity field of ALMA-J0107a exhibits a clear velocity gradient across the CO disk, and we find that ALMA-J0107a is characterized by an inclined rotating disk with a significant turbulence, that is, a deprojected maximum rotation velocity to velocity dispersion ratio of 1.3 0.3. We find that the dynamical mass of ALMA-J0107a within the CO-emitting disk computed from the derived kinetic parameters, (1.1 0.2) 1010 M o˙, is an order of magnitude smaller than the molecular gas mass derived from dust continuum emission, (3.2 1.6) 1011 M o˙. We suggest this source is magnified by a gravitational lens with a magnification of μ ⪆ 10, which is consistent with the measured offset from the empirical correlation between CO-line luminosity and width.

DOI： 10.3847/1538-4357/ac01cc

J-GEM optical and near-infrared follow-up of gravitational wave events during LIGO's and Virgo's third observing run

Sasada Mahito, Utsumi Yousuke, Itoh Ryosuke, Tominaga Nozomu, Tanaka Masaomi, Morokuma Tomoki, Yanagisawa Kenshi, Kawabata Koji S., Ohgami Takayuki, Yoshida Michitoshi, Abe Fumio, Adachi Ryo, Akitaya Hiroshi, Chong Yang, Daikuhara Kazuki, Hamasaki Ryo, Honda Satoshi, Hosokawa Ryohei, Iida Kota, Imazato Fumiya, Ishioka Chihiro, Iwasaki Takumi, Jian Mingjie, Kamei Yuhei, Kanai Takahiro, Kaneda Hidehiro, Kaneko Ayane, Katoh Noriyuki, Kawai Nobuyuki, Kubota Keiichiro, Kubota Yuma, Mamiya Hideo, Matsubayashi Kazuya, Morihana Kumiko, Murata Katsuhiro L., Nagayama Takahiro, Nakamura Noriatsu, Nakaoka Tatsuya, Niino Yuu, Nishinaka Yuki, Niwano Masafumi, Nogami Daisaku, Oasa Yumiko, Oeda Miki, Ogawa Futa, Ohsawa Ryou, Ohta Kouji, Oide Kohei, Onozato Hiroki, Sako Shigeyuki, Saito Tomoki, Sekiguchi Yuichiro, Shigeyama Toshikazu, Shigeyoshi Takumi, Shikauchi Minori, Shiraishi Kazuki, Suzuki Daisuke, Takagi Kengo, Takahashi Jun, Takarada Takuya, Takayama Masaki, Takeuchi Himeka, Tamura Yasuki, Tanaka Ryoya, Toma Sayaka, Tozuka Miyako, Uchida Nagomi, Uzawa Yoshinori, Yamanaka Masayuki, Yasuda Moeno, Yatsu Yoichi

PROGRESS OF THEORETICAL AND EXPERIMENTAL PHYSICS Vol. 2021 ( 5 ) 2021.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Progress of Theoretical and Experimental Physics

The Laser Interferometer Gravitational-wave Observatory Scientific Collaboration and Virgo Collaboration (LVC) sent out 56 gravitational-wave (GW) notices during the third observing run (O3). The Japanese Collaboration for Gravitational wave ElectroMagnetic follow-up (J-GEM) performed optical and near-infrared observations to identify and observe an electromagnetic (EM) counterpart. We constructed a web-based system that enabled us to obtain and share information on candidate host galaxies for the counterpart, and the status of our observations. Candidate host galaxies were selected from the GLADE catalog with a weight based on the 3D GW localization map provided by LVC. We conducted galaxy-targeted and wide-field blind surveys, real-time data analysis, and visual inspection of observed galaxies. We performed galaxy-targeted follow-ups to 23 GW events during O3, and the maximum probability covered by our observations reached 9.8%. Among these, we successfully started observations for 10 GW events within 0.5 days after the detection. This result demonstrates that our follow-up observation has the potential to constrain EM radiation models for a merger of binary neutron stars at a distance of up to ∼100 Mpc with a probability area of ≤ 500 deg 2.

DOI： 10.1093/ptep/ptab007

Variability of Late-time Radio Emission in the Superluminous Supernova PTF10hgi

B. Hatsukade, N. Tominaga, T. Morokuma, K. Morokuma-Matsui, Y. Tamura, K. Niinuma, M. Hayashi, Y. Matsuda, K. Motogi

The Astrophysical Journal Letters Vol. 911 ( 1 ) page： L1 - L1 2021.4

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

We report the time variability of the late-time radio emission in a Type I superluminous supernova (SLSN), PTF10hgi, at z = 0.0987. The Karl G. Jansky Very Large Array 3 GHz observations at 8.6 and 10 yr after the explosion both detected radio emission with a ∼40% decrease in flux density in the second epoch. This is the first report of a significant variability of the late-time radio light curve in an SLSN. Through combination with previous measurements in two other epochs, we constrained both the rise and decay phases of the radio light curve over three years, peaking at approximately 8-9 yr after the explosion with a peak luminosity of L3 GHz = 2 × 1021WHz-1. Possible scenarios for the origin of the variability are an active galactic nucleus (AGN) in the host galaxy, an afterglow caused by the interaction between an off-axis jet and circumstellar medium, and a wind nebula powered by a newly born magnetar. Comparisons with models show that the radio light curve can be reproduced by both the afterglow model and magnetar wind nebula model. Considering the flat radio spectrum at 1-15 GHz and an upper limit at 0.6 GHz obtained in previous studies, plausible scenarios are a low-luminosity flat-spectrum AGN or a magnetar wind nebula with a shallow injection spectral index. © 2021 The American Astronomical Society. All rights reserved.

DOI： 10.3847/2041-8213/abef03

Other Link： https://iopscience.iop.org/article/10.3847/2041-8213/abef03/pdf

Revisited Cold Gas Content with Atomic Carbon [C I] in z = 2.5 Protocluster Galaxies Reviewed

Minju M. Lee, Ichi Tanaka, Daisuke Iono, Ryohei Kawabe, Tadayuki Kodama, Kotaro Kohno, Toshiki Saito, Yoichi Tamura

The Astrophysical Journal Vol. 909 ( 2 ) page： 181 - 181 2021.3

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

We revisit the cold gas contents of galaxies in a protocluster at z = 2.49 using the lowest neutral atomic carbon transition [C i] 3 P 1 - 3 P 0 from Atacama Large Millimeter/submillimeter Array observations. We aim to test if the same gas-mass calibration adopted in field galaxies can be applied to protocluster galaxies. Five galaxies out of 16 targeted galaxies are detected in the [C i] line, and these are all previously detected in CO (3-2) and CO (4-3) and three in 1.1 mm dust continuum. We investigate the line luminosity relations between CO and [C i] in the protocluster and compare with other previous studies. We then compare the gas mass based on three gas tracers of [C i], CO(3-2), and dust if at least one of the last two tracers are available. Using the calibration adopted for field main-sequence galaxies, the [C i]-based gas measurements are lower than or comparable to the CO-based gas measurements by -0.35 dex at the lowest with the mean deviation of -0.14 dex. The differences between [C i]- and the dust- based measurements are relatively mild by up to 0.16 dex with the mean difference of 0.02 dex. Taking these all together with calibration uncertainties, with the [C i] line, we reconfirm our previous findings that the mean gas fraction is comparable to field galaxies for a stellar-mass range of . However, at least for these secure five detections, the depletion timescale decreases more rapidly with stellar mass than field galaxies that might be related to earlier quenching in dense environments.

DOI： 10.3847/1538-4357/abdbb5

Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/abdbb5/pdf

A puzzling non-detection of [O III] and [C II] from a z ≈ 7.7 galaxy observed with ALMA Reviewed

C. Binggeli, A. K. Inoue, T. Hashimoto, M. C. Toribio, E. Zackrisson, S. Ramstedt, K. Mawatari, Y. Harikane, H. Matsuo, T. Okamoto, K. Ota, I. Shimizu, Y. Tamura, Y. Taniguchi, H. Umehata

Astronomy & Astrophysics Vol. 646 page： A26 - A26 2021.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：EDP Sciences

<italic>Context.</italic> Characterizing the galaxy population in the early Universe holds the key to understanding the evolution of these objects and the role they played in cosmic reionization. However, there have been very few observations at the very highest redshifts to date.

<italic>Aims.</italic> In order to shed light on the properties of galaxies in the high-redshift Universe and their interstellar media, we observe the Lyman-<italic>α</italic> emitting galaxy <ext-link ext-link-type="aoi">z7_GSD_3811</ext-link> at <italic>z</italic> = 7.664 with bands 6 and 8 at the Atacama Large Millimeter/submillimeter Array (ALMA).

<italic>Methods.</italic> We target the far-infrared [O <sc>III</sc>] 88 <italic>μ</italic>m and [C <sc>II</sc>] 158 <italic>μ</italic>m emission lines and dust continuum in the star-forming galaxy z7_GSD_3811 with ALMA. We combine these measurements with earlier observations in the rest-frame ultraviolet (UV) in order to characterize the object and compare the results to those of earlier studies that observed [O <sc>III</sc>] and [C <sc>II</sc>] emission in high-redshift galaxies.

<italic>Results.</italic> The [O <sc>III</sc>] 88 <italic>μ</italic>m and [C <sc>II</sc>] 158 <italic>μ</italic>m emission lines are undetected at the position of z7_GSD_3811, with 3<italic>σ</italic> upper limits of 1.6 × 10<sup>8</sup> <italic>L</italic><sub>⊙</sub> and 4.0 × 10<sup>7</sup> <italic>L</italic><sub>⊙</sub>, respectively. We do not detect any dust continuum in band 6 nor band 8. The measured rms in the band 8 and band 6 continua are 26 and 9.9 <italic>μ</italic>Jy beam<sup>−1</sup>, respectively. Similar to several other high-redshift galaxies, z7_GSD_3811 exhibits low [C <sc>II</sc>] emission for its star formation rate compared to local galaxies. Furthermore, our upper limit on the [O <sc>III</sc>] line luminosity is lower than the previously observed [O <sc>III</sc>] lines in high-redshift galaxies with similar UV luminosities. Our ALMA band 6 and 8 dust continuum observations imply that z7_GSD_3811 likely has a low dust content, and our non-detections of the [O <sc>III</sc>] and [C <sc>II</sc>] lines could indicate that z7_GSD_3811 has a low metallicity (<italic>Z</italic> ≲ 0.1 <italic>Z</italic><sub>⊙</sub>).

DOI： 10.1051/0004-6361/202038180

Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). XII. Extended [C II] Structure (Merger or Outflow) in a z = 6.72 Red Quasar Reviewed

Takuma Izumi, Masafusa Onoue, Yoshiki Matsuoka, Michael A. Strauss, Seiji Fujimoto, Hideki Umehata, Masatoshi Imanishi, Taiki Kawamuro, Tohru Nagao, Yoshiki Toba, Kotaro Kohno, Nobunari Kashikawa, Kohei Inayoshi, Toshihiro Kawaguchi, Kazushi Iwasawa, Akio K. Inoue, Tomotsugu Goto, Shunsuke Baba, Malte Schramm, Hyewon Suh, Yuichi Harikane, Yoshihiro Ueda, John D. Silverman, Takuya Hashimoto, Yasuhiro Hashimoto, Soh Ikarashi, Daisuke Iono, Chien-Hsiu Lee, Kianhong Lee, Takeo Minezaki, Kouichiro Nakanishi, Suzuka Nakano, Yoichi Tamura, Ji-Jia Tang

The Astrophysical Journal Vol. 908 ( 2 ) page： 235 - 235 2021.2

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

We present Atacama Large Millimeter/submillimeter Array [C ii] 158 μm line and far-infrared (FIR) continuum emission observations toward HSC J120505.09-000027.9 (J1205-0000) at z = 6.72 with a beam size of ∼0.″8 × 0.″5 (or 4.1 kpc × 2.6 kpc), the most distant red quasar known to date. Red quasars are modestly reddened by dust and are thought to be in rapid transition from an obscured starburst to an unobscured normal quasar, driven by powerful active galactic nucleus (AGN) feedback that blows out a cocoon of interstellar medium. The FIR continuum of J1205-0000 is bright, with an estimated luminosity of L FIR ∼ 3 × 1012 L o˙. The [C ii] line emission is extended on scales of r ∼ 5 kpc, greater than that of the FIR continuum. The line profiles at the extended regions are complex and broad (FWHM ∼ 630-780 km s-1). Although it is not practical to identify the nature of this extended structure, possible explanations include (i) companion/merging galaxies and (ii) massive AGN-driven outflows. For the case of (i), the companions are modestly star-forming (∼10 M o˙ yr-1) but are not detected by our Subaru optical observations (y AB,5σ = 24.4 mag). For the case of (ii), our lower limit to the cold neutral outflow rate is ∼100 M o˙ yr-1. The outflow kinetic energy and momentum are both much lower than predicted in energy-conserving wind models, suggesting that the AGN feedback in this quasar is not capable of completely suppressing its star formation.

DOI： 10.3847/1538-4357/abd7ef

Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/abd7ef/pdf

The University of Tokyo Atacama Observatory 6.5m telescope: On-sky performance evaluations of the mid-infrared instrument MIMIZUKU on the Subaru telescope

Takafumi Kamizuka, Takashi Miyata, Shigeyuki Sako, Ryou Ohsawa, Kentaro Asano, Masahito S. Uchiyama, Tomohiro Mori, Yutaka Yoshida, Kengo Tachibana, Tsubasa Michifuji, Mizuho Uchiyama, Itsuki Sakon, Takashi Onaka, Hirokazu Kataza, Tsutomu Aoki, Mamoru Doi, Bunyo Hatsukade, Natsuko M. Kato, Kotaro Kohno, Masahiro Konishi, Takeo Minezaki, Tomoki Morokuma, Mizuki Numata, Kentaro Motohara, Hiroaki Sameshima, Takao Soyano, Hidenori Takahashi, Toshihiko Tanabe, Masuo Tanaka, Ken'ichi Tarusawa, Shintaro Koshida, Yoichi Tamura, Yasunori Terao, Kosuke Kushibiki, Hiroki Nakamura, Yuzuru Yoshii

Proceedings of the SPIE Vol. 11447 page： 114475X 2020.12

The University of Tokyo Atacama Observatory 6.5m Telescope: Overview and construction status

Yuzuru Yoshii, Mamoru Doi, Takashi Miyata, Kotaro Kohno, Masuo Tanaka, Takeo Minezaki, Shigeyuki Sako, Tomoki Morokuma, Toshihiko Tanabe, Bunyo Hatsukade, Masahiro Konishi, Takafumi Kamizuka, Kentaro Asano, Hiroaki Sameshima, Natsuko M. Kato, Mizuki Mumata, Hidenori Takahashi, Tsutomu Aoki, Takao Soyano, Ken'ichi Tarusawa, Kenji Yoshikawa, Kentaro Motohara, Yoichi Tamura, Shintaro Koshida, Toshihiro Handa, Leonardo Bronfman, Maria T. Ruiz, Mario Hamuy, Rene Mendez, Andres Escala

Proceedings of the SPIE Vol. 11445 page： 1144514 2020.12

Wind- and Operation-Induced Vibration Measurements of the Main Reflector of the Nobeyama 45 m Radio Telescope Reviewed

Ikumi Hashimoto, Masakatsu Chiba, Nozomi Okada, Hideo Ogawa, Ryohei Kawabe, Tetsuhiro Minamidani, Yoichi Tamura, Kimihiro Kimura

Journal of Vibration Engineering & Technologies Vol. 8 ( 6 ) page： 909 - 923 2020.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media {LLC}

Purpose: As deformations of the main reflector of a radio telescope directly affect the observations, the evaluation of the deformation is extremely important. Dynamic characteristics of the main reflector of the Nobeyama 45 m Radio Telescope, Japan, are measured under two conditions: the first is when the pointing observation is in operation, and the second is when the reflector is stationary and is subjected to wind loads when the observation is out of operation. Methods: Dynamic characteristics of the main reflector are measured using piezoelectric accelerometers. Results and Conclusion: When the telescope is in operation, a vibration mode with one nodal line horizontally or vertically on the reflector is induced, depending on whether the reflector is moving in the azimuthal or elevational planes, whereas under windy conditions, vibration modes that have two to four nodal lines are simultaneously induced. The predominant mode is dependent on the direction of wind loads.

DOI： 10.1007/s42417-020-00202-9

ALMA Deep Field in SSA22. A near-infrared-dark submillimeter galaxy at z = 4.0 Reviewed

Hideki Umehata, Ian Smail, A. M. Swinbank, Kotaro Kohno, Yoichi Tamura, Tao Wang, Yiping Ao, Bunyo Hatsukade, Mariko Kubo, Kouchiro Nakanishi, Natsuki N. Hayatsu

Astronomy & Astrophysics Vol. 640 page： L8 - L8 2020.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：EDP Sciences

Deep surveys with the Atacama Large Millimeter Array (ALMA) have uncovered a population of dusty star-forming galaxies which are faint or even undetected at optical to near-infrared wavelengths. Their faintness at short wavelengths makes the detailed characterization of the population challenging. Here we present a spectroscopic redshift identification and a characterization of one of these near-infrared-dark galaxies discovered by an ALMA deep survey. The detection of [C <sc>I</sc>](1–0) and CO(4–3) emission lines determines the precise redshift of the galaxy, ADF22.A2, to be <italic>z</italic> = 3.9913 ± 0.0008. On the basis of a multi-wavelength analysis, ADF22.A2 is found to be a massive, star-forming galaxy with a stellar mass of <italic>M</italic><sub>∗</sub> = 1.1<sub>−0.6</sub><sup>+1.3</sup> × 10<sup>11</sup> <italic>M</italic><sub>⊙</sub> and SFR = 430<sub>−150</sub><sup>+230</sup> <italic>M</italic><sub>⊙</sub> yr<sup>−1</sup>. The molecular gas mass was derived to be <italic>M</italic>(H<sub>2</sub>)<sup>[CI]</sup> = (5.9 ± 1.5)×10<sup>10</sup> <italic>M</italic><sub>⊙</sub>, indicating a gas fraction of ≈35%, and the ratios of <italic>L</italic><sub>[CI](1−0)</sub>/<italic>L</italic><sub>IR</sub> and <italic>L</italic><sub>[CI](1−0)</sub>/<italic>L</italic><sub>CO(4−3)</sub> suggest that the nature of the interstellar medium in ADF22.A2 is in accordance with those of other bright submillimeter galaxies. The properties of ADF22.A2, including the redshift, star-formation rate, stellar mass, and depletion time scale (<italic>τ</italic><sub>dep</sub> ≈ 0.1−0.2 Gyr), also suggest that ADF22.A2 has the characteristics expected for the progenitors of quiescent galaxies at <italic>z</italic> ≳ 3. Our results demonstrate the power of ALMA contiguous mapping and line scan, which help us to obtain an unbiased view of galaxy formation in the early Universe.

DOI： 10.1051/0004-6361/202038146

ALMA twenty-six arcmin^2 survey of GOODS-S at one millimeter (ASAGAO): Millimeter properties of stellar mass selected galaxies Reviewed

Yuki Yamaguchi, Kotaro Kohno, Bunyo Hatsukade, Tao Wang, Yuki Yoshimura, Yiping Ao, James S Dunlop, Eiichi Egami, Daniel Espada, Seiji Fujimoto, Natsuki H Hayatsu, Rob J Ivison, Tadayuki Kodama, Haruka Kusakabe, Tohru Nagao, Masami Ouchi, Wiphu Rujopakarn, Ken-ichi Tadaki, Yoichi Tamura, Yoshihiro Ueda, Hideki Umehata, Wei-Hao Wang

Publications of the Astronomical Society of Japan Vol. 72 ( 4 ) page： 69 2020.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

<title>Abstract</title>
We make use of the ALMA twenty-Six Arcmin2 survey of GOODS-S At One-millimeter (ASAGAO), deep 1.2 mm continuum observations of a 26-arcmin2 region in the Great Observatories Origins Deep Survey-South (GOODS-S) obtained with Atacama Large Millimeter/sub-millimeter Array (ALMA), to probe dust-enshrouded star formation in K-band selected (i.e., stellar mass selected) galaxies, which are drawn from the FourStar Galaxy Evolution Survey (ZFOURGE) catalog. Based on the ASAGAO combined map, which was created by combining ASAGAO and ALMA archival data in the GOODS-South field, we find that 24 ZFOURGE sources have 1.2 mm counterparts with a signal-to-noise ratio &gt;4.5 (1σ ≃ 30–70 μJy beam−1 at 1.2 mm). Their median redshift is estimated to be $z$median = 2.38 ± 0.14. They generally follow the tight relationship of the stellar mass versus star formation rate (i.e., the main sequence of star-forming galaxies). ALMA-detected ZFOURGE sources exhibit systematically larger infrared (IR) excess (IRX ≡ LIR/LUV) compared to ZFOURGE galaxies without ALMA detections even though they have similar redshifts, stellar masses, and star formation rates. This implies the consensus stellar-mass versus IRX relation, which is known to be tight among rest-frame-ultraviolet-selected galaxies, cannot fully predict the ALMA detectability of stellar-mass-selected galaxies. We find that ALMA-detected ZFOURGE sources are the main contributors to the cosmic IR star formation rate density at $z$ = 2–3.

DOI： 10.1093/pasj/psaa057

Other Link： http://academic.oup.com/pasj/article-pdf/72/4/69/33562710/psaa057.pdf

Spatially resolved molecular gas properties of host galaxy of Type I superluminous supernova SN 2017egm Reviewed

Bunyo Hatsukade, Kana Morokuma-Matsui, Masao Hayashi, Nozomu Tominaga, Yoichi Tamura, Kotaro Niinuma, Kazuhiro Motogi, Tomoki Morokuma, Yuichi Matsuda

Publications of the Astronomical Society of Japan Vol. 72 ( 4 ) page： L6 2020.8

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Oxford University Press (OUP)

<title>Abstract</title>
We present the results of CO(1–0) observations of the host galaxy of a Type I superluminous supernova (SLSN-I), SN 2017egm, one of the closest SLSNe-I at z = 0.03063, by using the Atacama Large Millimeter/submillimeter Array. The molecular gas mass of the host galaxy is Mgas = (4.8 ± 0.3) × 109 M⊙, placing it on the sequence of normal star-forming galaxies in an Mgas–star-formation rate (SFR) plane. The molecular hydrogen column density at the location of SN 2017egm is higher than that of the Type II SN PTF10bgl, which is also located in the same host galaxy, and those of other Type II and Ia SNe located in different galaxies, suggesting that SLSNe-I have a preference for a dense molecular gas environment. On the other hand, the column density at the location of SN 2017egm is comparable to those of Type Ibc SNe. The surface densities of molecular gas and the SFR at the location of SN 2017egm are consistent with those of spatially resolved local star-forming galaxies and follow the Schmidt–Kennicutt relation. These facts suggest that SLSNe-I can occur in environments with the same star-formation mechanism as in normal star-forming galaxies.

DOI： 10.1093/pasj/psaa052

Detections of far-infrared [OIII] and dust emission in a galaxy at z = 8.312: Early metal enrichment in the heart of the reionization era International coauthorship International journal

Y. Tamura, K. Mawatari, T. Hashimoto, A. K. Inoue, E. Zackrissonm, L. Christensen, C. Binggeli, Y. Matsuda, H. Matsuo, T. T. Takeuchi, R. S. Asano, K. Sunaga, I. Shimizu, T. Okamoto, N. Yoshida, M. Lee, T. Shibuya, Y. Taniguchi, H. Umehata, B. Hatsukade, K. Kohno, K. Ota

Proceedings of the International Astronomical Union Vol. 15 ( S341 ) page： 211 - 215 2020.6

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Publisher：Cambridge University Press (CUP)

<title>Abstract</title>We present ALMA detection of the [O <sc>iii</sc>] 88 <italic>μ</italic>m line and 850 <italic>μ</italic>m dust continuum emission in a <italic>Y</italic>-dropout Lyman break galaxy, MACS0416_Y1. The [O <sc>iii</sc>] detection confirms the object with a spectroscopic redshift to be <italic>z</italic> = 8.3118±0.0003. The 850 <italic>μ</italic>m continuum intensity (0.14 mJy) implies a large dust mass on the order of 4×10<sup>6</sup><italic>M</italic><sub>⊙</sub>. The ultraviolet-to-far infrared spectral energy distribution modeling, where the [O <sc>iii</sc>] emissivity model is incorporated, suggests the presence of a young (τ<sub>age</sub> ≍ 4 Myr), star-forming (SFR ≍ 60<italic>M</italic><sub>⊙</sub>yr<sup>−1</sup>), and moderately metal-polluted (<italic>Z</italic> ≍ 0.2<italic>Z</italic><sub>⊙</sub>) stellar component with a stellar mass of 3 × 10<sup>8</sup><italic>M</italic><sub>⊙</sub>. An analytic dust mass evolution model with a single episode of star formation does not reproduce the metallicity and dust mass in ≍ 4 Myr, suggesting an underlying evolved stellar component as the origin of the dust mass.

DOI： 10.1017/s1743921319002436

Other Link： http://stacks.iop.org/0004-637X/874/i=1/a=27?key=crossref.08977684a624e2093b8b0428fd4f056e

Large Population of ALMA Galaxies atz > 6 with Very High [Oiii] 88 mu m to [Cii] 158 mu m Flux Ratios: Evidence of Extremely High Ionization Parameter or PDR Deficit? Reviewed

Harikane Yuichi, Ouchi Masami, Inoue Akio K., Matsuoka Yoshiki, Tamura Yoichi, Bakx Tom, Fujimoto Seiji, Moriwaki Kana, Ono Yoshiaki, Nagao Tohru, Tadaki Ken-ichi, Kojima Takashi, Shibuya Takatoshi, Egami Eiichi, Ferrara Andrea, Gallerani Simona, Hashimoto Takuya, Kohno Kotaro, Matsuda Yuichi, Matsuo Hiroshi, Pallottini Andrea, Sugahara Yuma, Vallini Livia

ASTROPHYSICAL JOURNAL Vol. 896 ( 2 ) 2020.6

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