Faculty Profiles - TAMURA Yoichi

Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/ad1e5a/pdf

Molecular Outflow in the Reionization-epoch Quasar J2054-0005 Revealed by OH 119 μm Observations Reviewed International coauthorship

Salak, D; Hashimoto, T; Inoue, AK; Bakx, TJLC; Donevski, D; Tamura, Y; Sugahara, Y; Kuno, N; Miyamoto, Y; Fujimoto, S; Suphapolthaworn, S

The Astrophysical Journal Vol. 962 ( 1 ) 2024.2

The Extended [CII] under Construction? Observation of the Brightest High-z Lensed Star-forming Galaxy at z=6.2 Reviewed International coauthorship International journal Open Access

Yoshinobu Fudamoto, Akio K. Inoue, Dan Coe, Brian Welch, Ana Acebron, Massimo Ricotti, Nir Mandelker, Rogier A. Windhorst, Xinfeng Xu, Yuma Sugahara, Franz E. Bauer, Maruša Bradač, Larry D. Bradley, Jose M. Diego, Michael Florian, Brenda Frye, Seiji Fujimoto, Takuya Hashimoto, Alaina Henry, Guillaume Mahler, Pascal A. Oesch, Swara Ravindranath, Jane Rigby, Keren Sharon, Victoria Strait, Yoichi Tamura, Michele Trenti, Eros Vanzella, Erik Zackrisson, Adi Zitrin

The Astrophysical Journal Vol. 961 ( 1 ) page： 71 2024.1

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

We present results of [C II] 158 μm emission line observations, and report the spectroscopic redshift confirmation of a strongly lensed (μ ∼ 20) star-forming galaxy, MACS0308-zD1 at z = 6.2078 ± 0.0002. The [C II] emission line is detected with a signal-to-noise ratio >6 within the rest-frame UV-bright clump of the lensed galaxy (zD1.1) and exhibits multiple velocity components; the narrow [C II] has a velocity full width half maximum (FWHM) of 110 ± 20 km s−1, while broader [C II] is seen with an FWHM of 230 ± 50 km s−1. The broader [C II] component is blueshifted (−80 ± 20 km s−1) with respect to the narrow [C II] component, and has a morphology that extends beyond the UV-bright clump. We find that, while the narrow [C II] emission is most likely associated with zD1.1, the broader component is possibly associated with a physically distinct gas component from zD1.1 (e.g., outflowing or inflowing gas). Based on the nondetection of λ158μm dust continuum, we find that MACS0308-zDl's star formation activity occurs in a dust-free environment indicated by a strong upper limit of infrared luminosity ≲9 × 108 Le. Targeting this strongly lensed faint galaxy for follow-up Atacama Large Millimeter/submillimeter Array and JWST observations will be crucial to characterize the details of typical galaxy growth in the early Universe.

DOI： 10.3847/1538-4357/ad0f95

A 10.24-GHz-wide digital spectrometer array system for LMT-FINER: system design and laboratory performance verification International coauthorship International journal Open Access

Masato Hagimoto, Akio Taniguchi, Yoichi Tamura, Norika Okauchi, Hiroaki Kawamoto, Taku Nakajima, Takumi Hikosaka, Kenichi Harada, Toru Taniguchi, Takeshi Kamazaki, Takeshi Sakai, Kunihiko Tanaka, Ryohei Kawabe

Proceedings of SPIE - The International Society for Optical Engineering Vol. 13102 2024

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

For efficient spectroscopic redshift identification of early galaxies in the northern hemisphere, we aim to combine the Large Millimeter Telescope (LMT) with a wide-band heterodyne receiver, FINER, which will cover radio frequencies of 120-360 GHz and offer a 3-21 GHz intermediate frequency (IF) per sideband and polarization. To take full advantage of such wide IFs, we present a novel 10.24-GHz-wide digital spectrometer, DRS4 (Elecs Industry Co., Ltd.). It incorporates 20.48 Gsps samplers with an FPGA-based digital signal processing module. To mitigate the noise contamination from the image sideband, it is equipped with a digital sideband separation function to improve the sideband rejection up to 25 dB. Laboratory performance evaluations show that it exhibits an Allan time of at least ∼ 100 s and a total power dynamic range of at least 7 dB. These results demonstrate its capability of instantaneously wide-band spectroscopy toward high-redshift galaxies with position-switching observations.

DOI： 10.1117/12.3018296

Development Status of Wideband Millimeter-Wave Receivers for LMT-FINER International coauthorship International journal Open Access

Haoran Kang, Takafumi Kojima, Takeshi Sakai, Yoichi Tamura, Airi Tetsuka, Sho Masui, Tatsuya Takekoshi

Proceedings of SPIE - The International Society for Optical Engineering Vol. 13102 2024

Language：English Publishing type：Research paper (international conference proceedings) Publisher：SPIE-INT SOC OPTICAL ENGINEERING

Spectroscopic observations of the far-infrared [O iii] 88 µm and [C ii] 158 µm lines present a pathway to explore the mechanisms of the emergence of massive galaxies in the epoch of reionization and beyond, which is one of the most fundamental questions in astronomy. To address this question, the Far-Infrared Nebular Emission Receiver (FINER) project is developing two wideband dual-polarization sideband-separating heterodyne receivers at 120-210 GHz and 210-360 GHz for the Large Millimeter Telescope (LMT) in Mexico. Compared with Atacama Large Millimeter/submillimeter Array (ALMA), LMT provides 40% of ALMA's light-collecting area and a similar atmospheric transmittance, but FINER plans to have an instantaneous intermediate frequency (IF) of 3-21 GHz per sideband per polarization which is five times wider than current ALMA's bandwidth. Therefore, FINER is going to offer cutting-edge spectral scanning capability in the next several years. The project is currently in an active development phase. In this proceeding, the latest development status for FINER, including the optics, wideband waveguide components as well as low-noise superconductor-insulator-superconductor (SIS) mixers is reported.

DOI： 10.1117/12.3018190

Bright extragalactic ALMA redshift survey (BEARS) III: detailed study of emission lines from 71 Herschel targets

J0107a: A Barred Spiral Dusty Star-forming Galaxy at z = 2.467 Reviewed International coauthorship

The Astrophysical Journal Letters Vol. 958 ( 2 ) 2023.12

Molecular Abundance of the Circumnuclear Region Surrounding an Active Galactic Nucleus in NGC 1068 Based on an Imaging Line Survey in the 3 mm Band with ALMA Reviewed International coauthorship International journal Open Access

Taku Nakajima, Shuro Takano, Tomoka Tosaki, Akio Taniguchi, Nanase Harada, Toshiki Saito, Masatoshi Imanishi, Yuri Nishimura, Takuma Izumi, Yoichi Tamura, Kotaro Kohno, Eric Herbst

The Astrophysical Journal Vol. 955 ( 1 ) page： 27 - 27 2023.9

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

We present an imaging molecular line survey in the 3 mm band (85–114 GHz) focused on one of the nearest galaxies with an active galactic nucleus (AGN), NGC 1068, based on observations taken with the Atacama Large Millimeter/submillimeter Array. Distributions of 23 molecular transitions are obtained in the central ∼3 kpc region, including both the circumnuclear disk (CND) and starburst ring (SBR) with 60 and 350 pc resolution. The column densities and relative abundances of all the detected molecules are estimated under the assumption of local thermodynamic equilibrium in the CND and SBR. Then, we discuss the physical and chemical effects of the AGN on molecular abundance corresponding to the observation scale. We found that H13CN, SiO, HCN, and H13CO+ are abundant in the CND relative to the SBR. In contrast, 13CO is more abundant in the SBR. Based on the calculated column density ratios of N(HCN)/N(HCO+), N(HCN)/N(CN), and other molecular distributions, we conclude that the enhancement of HCN in the CND may be due to high-temperature environments resulting from strong shocks, which are traced by the SiO emission. Moreover, the abundance of CN in the CND is significantly lower than the expected value of the model calculations in the region affected by strong radiation. The expected strong X-ray irradiation from the AGN has a relatively lower impact on the molecular abundance in the CND than mechanical feedback.

DOI： 10.3847/1538-4357/ace4c7

Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/ace4c7/pdf

Characterizing CO Emitters in the SSA22-AzTEC26 Field Reviewed International coauthorship International journal Open Access

Shuo Huang, Hideki Umehata, Ryohei Kawabe, Kotaro Kohno, Minju Lee, Yoichi Tamura, Bunyo Hatsukade, Ken Mawatari

The Astrophysical Journal Vol. 953 ( 1 ) page： 75 2023.8

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

We report the physical characterization of four CO emitters detected near the bright submillimeter galaxy (SMG) SSA22-AzTEC26. We analyze the data from Atacama Large Millimeter/submillimeter Array band 3, 4, and 7 observations of the SSA22-AzTEC26 field. In addition to the targeted SMG, we detect four line emitters with signal-to-noise ratio >5.2 in the cube smoothed with a 300 km s−1 FWHM Gaussian filter. All four sources have NIR counterparts within 1″. We perform UV-to-FIR spectral energy distribution modeling to derive the photometric redshifts and physical properties. Based on the photometric redshifts, we reveal that two of them are CO(2-1) at redshifts of 1.113 and 1.146 and one is CO(3-2) at z = 2.124. The three sources are massive galaxies with a stellar mass ≳1010.5 M ⊙, but have different levels of star formation. Two lie within the scatter of the main sequence (MS) of star-forming galaxies at z ∼ 1-2, and the most massive galaxy lies significantly below the MS. However, all three sources have a gas fraction within the scatter of the MS scaling relation. This shows that a blind CO line search can detect massive galaxies with low specific star formation rates that still host large gas reservoirs and that it also complements targeted surveys, suggesting later gas acquisition and the need for other mechanisms in addition to gas consumption to suppress star formation.

DOI： 10.3847/1538-4357/ace0c0

Big Three Dragons: Molecular Gas in a Bright Lyman-break Galaxy at z = 7.15 Reviewed International coauthorship International journal Open Access

Takuya Hashimoto, Akio K. Inoue, Yuma Sugahara, Yoshinobu Fudamoto, Seiji Fujimoto, K. K. Knudsen, Hiroshi Matsuo, Yoichi Tamura, Satoshi Yamanaka, Yuichi Harikane, Nario Kuno, Yoshiaki Ono, Dragan Salak, Nozomi Ishii

The Astrophysical Journal Vol. 952 ( 1 ) 2023.7

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

We report Atacama Large Millimeter/submillimeter Array Band 3 observations of CO(6−5), CO(7−6), and [C i](2−1) in B14-65666 (“Big Three Dragons”), one of the brightest Lyman-break galaxies at z > 7 in the rest-frame ultraviolet continuum, far-infrared continuum, and emission lines of [O iii] 88 μm and [C ii] 158 μm. CO(6−5), CO(7−6), and [C i](2−1), whose 3σ upper limits on the luminosities are approximately 40 times fainter than the [C ii] luminosity, are all not detected. The L [C II]/L CO(6-5) and L [C II]/L CO(7-6) ratios are higher than the typical ratios obtained in dusty star-forming galaxies or quasar host galaxies at similar redshifts, and they may suggest a lower gas density in the photodissociated region in B14-65666. By using the (1) [C ii] luminosity, (2) dust mass-to-gas mass ratio, and (3) a dynamical mass estimate, we find that the molecular gas mass (M mol) is (0.05-11) × 1010 M ⊙. This value is consistent with the upper limit inferred from the nondetection of mid-J CO and [C i](2−1). Despite the large uncertainty in M mol, we estimate a molecular gas-to-stellar mass ratio (μ gas) of 0.65-140 and a gas depletion time (τ dep) of 2.5-550 Myr; these values are broadly consistent with those of other high-redshift galaxies. B14-65666 could be an ancestor of a passive galaxy at z ≳ 4 if no gas is fueled from outside the galaxy.

DOI： 10.3847/1538-4357/acdd5c

Detections of [C ii] 158 μm and [O iii] 88 μm in a Local Lyman Continuum Emitter, Mrk 54, and Its Implications to High-redshift ALMA Studies Reviewed International coauthorship International journal Open Access

Ryota Ura, Takuya Hashimoto, Akio K. Inoue, Dario Fadda, Matthew Hayes, Johannes Puschnig, Erik Zackrisson, Yoichi Tamura, Hiroshi Matsuo, Ken Mawatari, Yoshinobu Fudamoto, Masato Hagimoto, Nario Kuno, Yuma Sugahara, Satoshi Yamanaka, Tom J. L. C. Bakx, Yurina Nakazato, Mitsutaka Usui, Hidenobu Yajima, Naoki Yoshida

The Astronomical Journal Vol. 948 ( 1 ) page： 3 2023.5

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

We present integral field, far-infrared (FIR) spectroscopy of Mrk 54, a local Lyman continuum emitter, obtained with FIFI-LS on the Stratospheric Observatory for Infrared Astronomy. This is only the second time, after Haro 11, that [C ii] 158 mu m and [O iii] 88 mu m spectroscopy of the known LCEs have been obtained. We find that Mrk 54 has a strong [C ii] emission that accounts for similar to 1% of the total FIR luminosity, whereas it has only moderate [O iii] emission, resulting in the low [O iii]/[C ii] luminosity ratio of 0.22 +/- 0.06. In order to investigate whether [O iii]/[C ii] is a useful tracer of f (esc) (LyC escape fraction), we examine the correlations of [O iii]/[C ii] and (i) the optical line ratio of O-32 equivalent to [O iii] 5007 angstrom/[O ii] 3727 angstrom, (ii) specific star formation rate, (iii) [O iii] 88 mu m/[O i] 63 mu m ratio, (iv) gas-phase metallicity, and (v) dust temperature based on a combined sample of Mrk 54 and the literature data from the Herschel Dwarf Galaxy Survey and the LITTLE THINGS Survey. We find that galaxies with high [O iii]/[C ii] luminosity ratios could be the result of high ionization (traced by O-32), bursty star formation, high ionized-to-neutral gas volume filling factors (traced by [O iii] 88 mu m/[O i] 63 mu m), and low gas-phase metallicities, which is in agreement with theoretical predictions. We present an empirical relation between the [O iii]/[C ii] ratio and f (esc) based on the combination of the [O iii]/[C ii] and O-32 correlation, and the known relation between O-32 and f (esc). The relation implies that high-redshift galaxies with high [O iii]/[C ii] ratios revealed by the Atacama Large Millimeter/submillimeter Array may have f (esc) greater than or similar to 0.1, significantly contributing to the cosmic reionization.

DOI： 10.3847/1538-4357/acc530

The SSA22 H i Tomography Survey (SSA22-HIT). I. Data Set and Compiled Redshift Catalog Reviewed International coauthorship International journal Open Access

Ken Mawatari, Akio K. Inoue, Toru Yamada, Tomoki Hayashino, J. Xavier Prochaska, Khee-Gan Lee, Nicolas Tejos, Nobunari Kashikawa, Takuya Otsuka, Satoshi Yamanaka, David J. Schlegel, Yuichi Matsuda, Joseph F. Hennawi, Ikuru Iwata, Hideki Umehata, Shiro Mukae, Masami Ouchi, Yuma Sugahara, Yoichi Tamura

The Astronomical Journal Vol. 165 ( 5 ) page： 208 2023.5

Hagimoto, M; Bakx, TJLC; Serjeant, S; Bendo, GJ; Urquhart, SA; Eales, S; Harrington, KC; Tamura, Y; Umehata, H; Berta, S; Cooray, AR; Cox, P; De Zotti, G; Lehnert, MD; Riechers, DA; Scott, D; Temi, P; van der Werf, PP; Yang, C; Amvrosiadis, A; Andreani, PM; Baker, AJ; Beelen, A; Borsato, E; Buat, V; Butler, KM; Dannerbauer, H; Dunne, L; Dye, S; Enia, AFM; Fan, L; Gavazzi, R; González-Nuevo, J; Harris, AI; Herrera, CN; Hughes, DH; Ismail, D; Ivison, RJ; Jones, B; Kohno, K; Krips, M; Lagache, G; Marchetti, L; Massardi, M; Messias, H; Negrello, M; Neri, R; Omont, A; Perez-Fournon, I; Sedgwick, C; Smith, MWL; Stanley, F; Verma, A; Vlahakis, C; Ward, B; Weiner, C; Weiss, A; Young, AJ

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Vol. 521 ( 4 ) page： 5508 - 5535 2023.3

Language：English Publishing type：Research paper (scientific journal) Publisher：Monthly Notices of the Royal Astronomical Society

We analyse the molecular and atomic emission lines of 71 bright Herschel-selected galaxies between redshifts 1.4 and 4.6 detected by the Atacama Large Millimeter/submillimeter Array. These lines include a total of 156 CO, [C i], and H2O emission lines. For 46 galaxies, we detect two transitions of CO lines, and for these galaxies we find gas properties similar to those of other dusty star-forming galaxy (DSFG) samples. A comparison to photodissociation models suggests that most of Herschel-selected galaxies have similar interstellar medium conditions as local infrared-luminous galaxies and high-redshift DSFGs, although with denser gas and more intense far-ultraviolet radiation fields than normal star-forming galaxies. The line luminosities agree with the luminosity scaling relations across five orders of magnitude, although the star formation and gas surface density distributions (i.e. Schmidt-Kennicutt relation) suggest a different star formation phase in our galaxies (and other DSFGs) compared to local and low-redshift gas-rich, normal star-forming systems. The gas-to-dust ratios of these galaxies are similar to Milky Way values, with no apparent redshift evolution. Four of 46 sources appear to have CO line ratios in excess of the expected maximum (thermalized) profile, suggesting a rare phase in the evolution of DSFGs. Finally, we create a deep stacked spectrum over a wide rest-frame frequency (220-890 GHz) that reveals faint transitions from HCN and CH, in line with previous stacking experiments.

DOI： 10.1093/mnras/stad784

ALMA Observations of CO Emission from Luminous Lyman-break Galaxies at z = 6.0293–6.2037 Reviewed

Updated Measurements of [O iii] 88 μm, [C ii] 158 μm, and Dust Continuum Emission from a z = 7.2 Galaxy Reviewed International coauthorship International journal Open Access

Yi W. Ren, Yoshinobu Fudamoto, Akio K. Inoue, Yuma Sugahara, Tsuyoshi Tokuoka, Yoichi Tamura, Hiroshi Matsuo, Kotaro Kohno, Hideki Umehata, Takuya Hashimoto, Rychard J. Bouwens, Renske Smit, Nobunari Kashikawa, Takashi Okamoto, Takatoshi Shibuya, Ikkoh Shimizu

The Astrophysical Journal Vol. 945 ( 1 ) page： 69 2023.3

Bright Extragalactic ALMA Redshift Survey (BEARS) III: Detailed study of emission lines from 71 Herschel targets Reviewed

Hagimoto, M, Bakx, T. J. L. C, Serjeant, S, Bendo, G. J, Urquhart, S. A, Eales, S, Harrington, K. C, Tamura, Y, Umehata, H, Berta, S, Cooray, A. R, Cox, P, De Zotti, G, Lehnert, M. D, Riechers, D. A, Scott, D, Temi, P, van der Werf, P. P, Yang, C, Amvrosiadis, A, Andreani, P. M, Baker, A. J, Beelen, A, Borsato, E, Buat, V, Butler, K. M, Dannerbauer, H, Dunne, L, Dye, S, Enia, A. F. M, Fan, L, Gavazzi, R, Gonzalez-Nuevo, J, Harris, A. I, Herrera, C. N, Hughes, D. H, Ismail, D, Ivison, R. J, Jones, B, Kohno, K, Krips, M, Lagache, G, Marchetti, L, Massardi, M, Messias, H, Negrello, M, Neri, R, Omont, A, Perez-Fournon, I, Sedgwick, C, Smith, M. W. L, Stanley, F, Verma, A, Vlahakis, C, Ward, B, Weiner, C, Weiss, A, Young, A. J

Monthly Notices of the Royal Astronomical Society 2023.3

The SCUBA-2 Large eXtragalactic Survey: 850μm map, catalogue and the bright-end number counts of the XMM-LSS field Reviewed International journal Open Access

T K Garratt, J E Geach, Y Tamura, K E K Coppin, M Franco, Y Ao, C -C Chen, C Cheng, D L Clements, Y S Dai, H Dannerbauer, T R Greve, B Hatsukade, H S Hwang, L Jiang, K Kohno, M P Koprowski, M J Michałowski, M Sawicki, D Scott, H Shim, T T Takeuchi, W -H Wang, Y Q Xue, C Yang

Monthly Notices of the Royal Astronomical Society Vol. 520 ( 3 ) page： 3669 - 3687 2023.2

Deep ALMA redshift search of a z ~ 12 GLASS-JWST galaxy candidate Reviewed International journal Open Access

Bakx, Tom, Zavala, Jorge A, Mitsuhashi, Ikki, Treu, Tommaso, Fontana, Adriano, Tadaki, Ken-ichi, Casey, Caitlin M, Castellano, Marco, Glazebrook, Karl, Hagimoto, Masato, Ikeda, Ryota, Jones, Tucker, Leethochawalit, Nicha, Mason, Charlotte, Morishita, Takahiro, Nanayakkara, Themiya, Pentericci, Laura, Roberts-Borsani, Guido, Santini, Paola, Serjeant, Stephen, Tamura, Yoichi, Trenti, Michele, Vanzella, Eros

Monthly Notices of the Royal Astronomical Society Vol. 519 ( 4 ) page： 5076 - 5085 2023.1

Yoshiaki Ono, Seiji Fujimoto, Yuichi Harikane, Masami Ouchi, Livia Vallini, Andrea Ferrara, Takatoshi Shibuya, Andrea Pallottini, Akio K. Inoue, Masatoshi Imanishi, Kazuhiro Shimasaku, Takuya Hashimoto, Chien-Hsiu Lee, Yuma Sugahara, Yoichi Tamura, Kotaro Kohno, Malte Schramm

The Astrophysical Journal Vol. 941 ( 1 ) page： 74 - 74 2022.12

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

Abstract

We present our new Atacama Large Millimeter/submillimeter Array (ALMA) observations targeting CO(6–5) emission from three luminous Lyman-break galaxies (LBGs) at zspec = 6.0293–6.2037 found in the Subaru/Hyper Suprime-Cam survey, whose [O iii] 88 μm and [C ii] 158 μm emissions have been detected with ALMA. We find a marginal detection of the CO(6–5) line from one of our LBGs, J0235–0532, at the ≃4σ significance level and obtain upper limits for the other two LBGs, J1211–0118 and J0217–0208. Our z = 6 luminous LBGs are consistent with the previously found correlation between the CO luminosity and the infrared luminosity. The unique ensemble of the multiple far-infrared emission lines and underlying continuum fed to a photodissociation region model reveals that J0235–0532 has a relatively high density of hydrogen nuclei nH that is comparable to those of low-z (U)LIRGs, quasars, and Galactic star-forming regions with high nH values, while the other two LBGs have lower nH consistent with local star-forming galaxies. By carefully taking account of various uncertainties, we obtain constraints on total gas mass and gas surface density from their CO luminosity measurements. We find that J0235–0532 is located below the Kennicutt–Schmidt (KS) relation, comparable to the z = 5.7 LBG, HZ10, previously detected with CO(2–1). Combined with previous results for dusty starbursts at similar redshifts, the KS relation at z = 5–6 is on average consistent with the local one.

DOI： 10.3847/1538-4357/ac9ea6