研究者詳細 - 田村　陽一

論文 - 田村　陽一

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Bound star clusters observed in a lensed galaxy 460 Myr after the Big Bang 査読有り国際共著国際誌 Open Access

Adamo, A; Bradley, LD; Vanzella, E; Claeyssens, A; Welch, B; Diego, JM; Mahler, G; Oguri, M; Sharon, K; Abdurro'uf; Hsiao, TYY; Xu, XF; Messa, M; Lassen, AE; Zackrisson, E; Brammer, G; Coe, D; Kokorev, V; Ricotti, M; Zitrin, A; Fujimoto, S; Inoue, AK; Resseguier, T; Rigby, JR; Jiménez-Teja, Y; Windhorst, RA; Hashimoto, T; Tamura, Y

NATURE 632 巻 ( 8025 ) 頁： 513 - 516 2024年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature

The Cosmic Gems arc is among the brightest and highly magnified galaxies observed at redshift z ≈ 10.2 (ref. 1). However, it is an intrinsically ultraviolet faint galaxy, in the range of those now thought to drive the reionization of the Universe2–4. Hitherto the smallest features resolved in a galaxy at a comparable redshift are between a few hundreds and a few tens of parsecs (pc)5,6. Here we report JWST observations of the Cosmic Gems. The light of the galaxy is resolved into five star clusters located in a region smaller than 70 pc. They exhibit minimal dust attenuation and low metallicity, ages younger than 50 Myr and intrinsic masses of about 106M⊙. Their lensing-corrected sizes are approximately 1 pc, resulting in stellar surface densities near 105M⊙ pc−2, three orders of magnitude higher than typical young star clusters in the local Universe7. Despite the uncertainties inherent to the lensing model, they are consistent with being gravitationally bound stellar systems, that is, proto-globular clusters. We conclude that star cluster formation and feedback likely contributed to shaping the properties of galaxies during the epoch of reionization.

DOI： 10.1038/s41586-024-07703-7

FINER: Far-Infrared Nebular Emission Receiver for the Large Millimeter Telescope 国際共著国際誌 Open Access

Tamura, Y; Sakai, T; Kawabe, R; Kojima, T; Taniguchi, A; Takekoshi, T; Kang, HR; Shan, WL; Hagimoto, M; Okauchi, N; Tetsuka, A; Inoue, AK; Kohno, K; Tanaka, K; Bakx, TJLC; Fudamoto, Y; Fujita, K; Harikane, Y; Hashimoto, T; Hatsukade, B; Hughes, DH; Iino, T; Kimura, Y; Maezawa, H; Matsuda, Y; Mawatari, K; Nakajima, T; Nakatsubo, S; Oshima, T; Sagawa, H; Schloerb, FP; Takahashi, S; Taniguchi, K; Tsujita, A; Umehata, H; Yonetsu, T; Yun, MS

MILLIMETER, SUBMILLIMETER, AND FAR-INFRARED DETECTORS AND INSTRUMENTATION FOR ASTRONOMY XII, PT 1 13102 巻 2024年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Proceedings of SPIE - The International Society for Optical Engineering

Unveiling the emergence and prevalence of massive/bright galaxies during the epoch of reionization and beyond, within the first 600 million years of the Universe, stands as a pivotal pursuit in astronomy. Remarkable progress has been made by JWST in identifying an immense population of bright galaxies, which hints at exceptionally efficient galaxy assembly processes. However, the underlying physical mechanisms propelling their rapid growth remain unclear. With this in mind, millimeter and submillimeter-wave spectroscopic observations of redshifted far-infrared spectral lines, particularly the [O iii] 88 µm and [C ii] 158 µm lines, offers a crucial pathway to address this fundamental query. To this end, we develop a dual-polarization sideband-separating superconductor-insulator-superconductor (SIS) mixer receiver, FINER, for the Large Millimeter Telescope (LMT) situated in Mexico. Harnessing advancements from ALMA's wideband sensitivity upgrade (WSU) technology, FINER covers radio frequencies spanning 120-360 GHz, delivering an instantaneous intermediate frequency (IF) of 3-21 GHz per sideband per polarization, which is followed by a set of 10.24 GHz-wide digital spectrometers. At 40% of ALMA's light-collecting area, the LMT's similar atmospheric transmittance and FINER's 5 times wider bandwidth compared to ALMA culminate in an unparalleled spectral scanning capability in the northern hemisphere, paving the way for finer spectral-resolution detection of distant galaxies.

DOI： 10.1117/12.3017788

Reionization and the ISM/Stellar Origins with JWST and ALMA (RIOJA): The Core of the Highest-redshift Galaxy Overdensity at <i>z</i>=7.88 Confirmed by NIRSpec/JWST 査読有り国際共著国際誌 Open Access

Hashimoto, T; Alvarez-Márquez, J; Fudamoto, Y; Colina, L; Inoue, AK; Nakazato, Y; Ceverino, D; Yoshida, N; Costantin, L; Sugahara, Y; Gómez, AC; Blanco-Prieto, C; Mawatari, K; Arribas, S; Marques-Chaves, R; Pereira-Santaella, M; Bakx, TJLC; Hagimoto, M; Hashigaya, T; Matsuo, H; Tamura, Y; Usui, M; Ren, YW

ASTROPHYSICAL JOURNAL LETTERS 955 巻 ( 1 ) 頁： L2 2023年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Astrophysical Journal Letters

The protoclusters in the epoch of reionization, traced by galaxy overdensity regions, are ideal laboratories for studying the process of stellar assembly and cosmic reionization. We present the spectroscopic confirmation of the core of the most distant protocluster at z = 7.88, A2744-z7p9OD, with the James Webb Space Telescope NIRSpec integral field unit spectroscopy. The core region includes as many as four galaxies detected in [O iii] 4960 and 5008 Å in a small area of ∼3″ × 3″, corresponding to ∼11 × 11 kpc, after the lensing magnification correction. Three member galaxies are also tentatively detected in dust continuum in Atacama Large Millimeter/submillimeter Array Band 6, which is consistent with their red ultraviolet continuum slopes, β ∼ −1.3. The member galaxies have stellar masses in the range of log(M */M ⊙) ∼7.6-9.2 and star formation rates of ∼3-50 M ⊙ yr−1, showing a diversity in their properties. FirstLight cosmological simulations reproduce the physical properties of the member galaxies including the stellar mass, [O iii] luminosity, and dust-to-stellar mass ratio, and predict that the member galaxies are on the verge of merging in a few to several tens of Myr to become a large galaxy with M * ∼ 6 × 109 M ⊙. The presence of a multiple merger and evolved galaxies in the core region of A2744-z7p9OD indicates that environmental effects are already at work 650 Myr after the Big Bang.

DOI： 10.3847/2041-8213/acf57c

The 300 pc Resolution Imaging of a <i>z</i>=8.31 Galaxy: Turbulent Ionized Gas and Potential Stellar Feedback 600 Million Years after the Big Bang 査読有り国際共著国際誌 Open Access

Tamura, Y; Bakx, TJLC; Inoue, AK; Hashimoto, T; Tokuoka, T; Imamura, C; Hatsukade, B; Lee, MM; Moriwaki, K; Okamoto, T; Ota, K; Umehata, H; Yoshida, N; Zackrisson, E; Hagimoto, M; Matsuo, H; Shimizu, I; Sugahara, Y; Takeuchi, TT

ASTROPHYSICAL JOURNAL 952 巻 ( 1 ) 頁： 9 2023年7月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Astrophysical Journal

We present the results of 300 pc resolution Atacama Large Millimeter/submillimeter Array imaging of the [O iii] 88 μm line and dust continuum emission from a z = 8.312 Lyman-break galaxy MACS0416_Y1. The velocity-integrated [O iii] emission has three peaks that are likely associated with three young stellar clumps of MACS0416_Y1, while the channel map shows a complicated velocity structure with little indication of a global velocity gradient unlike what was found in [C ii] 158 μm at a larger scale, suggesting random bulk motion of ionized gas clouds inside the galaxy. In contrast, dust emission appears as two individual clumps apparently separating or bridging the [O iii]/stellar clumps. The cross-correlation coefficient between dust and ultraviolet-related emission (i.e., [O iii] and ultraviolet continuum) is unity on a galactic scale, while it drops at <1 kpc, suggesting well-mixed geometry of multiphase interstellar media on subkiloparsec scales. If the cutoff scale characterizes different stages of star formation, the cutoff scale can be explained by gravitational instability of turbulent gas. We also report on a kiloparsec-scale off-center cavity embedded in the dust continuum image. This could be a superbubble producing galactic-scale outflows, since the energy injection from the 4 Myr starburst suggested by a spectral energy distribution analysis is large enough to push the surrounding media creating a kiloparsec-scale cavity.

DOI： 10.3847/1538-4357/acd637

The bright extragalactic ALMA redshift survey (BEARS) - II. Millimetre photometry of gravitational lens candidates 国際共著 Open Access

Bendo, GJ; Urquhart, SA; Serjeant, S; Bakx, T; Hagimoto, M; Cox, P; Neri, R; Lehnert, MD; Dannerbauer, H; Amvrosiadis, A; Andreani, P; Baker, AJ; Beelen, A; Berta, S; Borsato, E; Buat, ; Butler, KM; Cooray, A; De Zotti, G; Dunne, L; Dye, S; Eales, S; Enia, A; Fan, L; Gavazzi, R; González-Nuevo, J; Harris, A; Herrera, CN; Hughes, DH; Ismail, D; Jones, BM; Kohno, K; Krips, M; Lagache, G; Marchetti, L; Massardi, M; Messias, H; Negrello, M; Omont, A; Pérez-Fournon, ; Riechers, DA; Scott, D; Smith, MWL; Stanley, F; Tamura, Y; Temi, P; van der Werf, P; Verma, A; Vlahakis, C; Weiss, A; Yang, C; Young, AJ

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 522 巻 ( 2 ) 頁： 2995 - 3017 2023年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Monthly Notices of the Royal Astronomical Society

We present 101- and 151-GHz ALMA continuum images for 85 fields selected from Herschel observations that have 500-μm flux densities >80 mJy and 250–500-μm colours consistent with z > 2, most of which are expected to be gravitationally lensed or hyperluminous infrared galaxies. Approximately half of the Herschel 500-μm sources were resolved into multiple ALMA sources, but 11 of the 15 brightest 500-μm Herschel sources correspond to individual ALMA sources. For the 37 fields containing either a single source with a spectroscopic redshift or two sources with the same spectroscopic redshift, we examined the colour temperatures and dust emissivity indices. The colour temperatures only vary weakly with redshift and are statistically consistent with no redshift-dependent temperature variations, which generally corresponds to results from other samples selected in far-infrared, submillimetre, or millimetre bands but not to results from samples selected in optical or near-infrared bands. The dust emissivity indices, with very few exceptions, are largely consistent with a value of 2. We also compared spectroscopic redshifts to photometric redshifts based on spectral energy distribution templates designed for infrared-bright high-redshift galaxies. While the templates systematically underestimate the redshifts by ∼15 per cent, the inclusion of ALMA data decreases the scatter in the predicted redshifts by a factor of ∼2, illustrating the potential usefulness of these millimetre data for estimating photometric redshifts.

DOI： 10.1093/mnras/stac3771

Possible Systematic Rotation in the Mature Stellar Population of a z = 9.1 Galaxy

Tokuoka, T; Inoue, AK; Hashimoto, T; Ellis, RS; Laporte, N; Sugahara, Y; Matsuo, H; Tamura, Y; Fudamoto, Y; Moriwaki, K; Roberts-Borsani, G; Shimizu, I; Yamanaka, S; Yoshida, N; Zackrisson, E; Zheng, W

ASTROPHYSICAL JOURNAL LETTERS 944 巻 ( 2 ) 頁： 19 2023年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Astrophysical Journal Letters

In Section 4, dynamical modeling, we erroneously omit the redshift dependence of the gravitational lensing effect. For the source redshift of z = 9.1096, the lensing magnification factor predicted by the glafic model (Kawamata et al. 2016) is 17.4 instead of 4.7 in the published article. We have redone the dynamical modeling with the correct lensing effect for the source redshift. The correct results are summarized in the revised Table 1. Figure 2 bottom panel and Figures 3 and 4 are also revised with the correct treatment of the gravitational lensing effect. The conclusion does not change, while the numbers of the best-fit model and their uncertainties have changed.

DOI： 10.3847/2041-8213/acb935

Data science based efficient and automated spectroscopy for submillimeter single-dish telescopes

Taniguchi A., Tamura Y., Ikeda S., Takekoshi T., Kawabe R., Kohno K., Sakai T.

2023 35th General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2023 2023年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：2023 35th General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2023

In this paper, we present a new data scientific approach for efficient and automated spectroscopy with millimeter and submillimeter single-dish telescopes. The proposed approach avoids direct subtraction between two noisy spectra (i.e. on-source and off-source spectra) that is common in the current data reduction: It then offers us to improve the observation sensitivity by a factor of 2 and reduce artificial baseline ripples in parallel with developing observational instruments. We demonstrate such upgrades in the real observed spectra taken by existing large millimeter single-dish telescopes. We finally discuss the application of the proposed approach for the future large submillimeter single-dish telescopes that will yield petabytes of data resulting from sensitive, wide field (1°2), and wide band (>100 GHz) imaging spectroscopy.

DOI： 10.23919/URSIGASS57860.2023.10265475

Wavefront sensor for millimeter/submillimeter-wave adaptive optics based on aperture-plane interferometry

Tamura Yoichi, Kawabe Ryohei, Fukasaku Yuhei, Kimura Kimihiro, Ueda Tetsutaro, Taniguchi Akio, Okada Nozomi, Ogawa Hideo, Hashimoto Ikumi, Minamidani Tetsuhiro, Kawaguchi Noriyuki, Kuno Nario, Togami Yohei, Hagimoto Masato, Nakano Satoya, Matsuda Keiichi, Okumura Sachiko K., Nakamura Tomoko, Kurita Mikio, Takekoshi Tatsuya, Oshima Tai, Onishi Toshikazu, Kohno Kotaro

GROUND-BASED AND AIRBORNE TELESCOPES VIII 11445 巻頁： 114451N 2020年

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Proceedings of SPIE - The International Society for Optical Engineering

We present a concept of a millimeter wavefront sensor that allows real-time sensing of the surface of a groundbased millimeter/submillimeter telescope. It is becoming important for ground-based millimeter/submillimeter astronomy to make telescopes larger with keeping their surface accurate. To establish 'millimetric adaptive optics (MAO)' that instantaneously corrects the wavefront degradation induced by deformation of telescope optics, our wavefront sensor based on radio interferometry measures changes in excess path lengths from characteristic positions on the primary mirror surface to the focal plane. This plays a fundamental role in planed 50-m class submillimeter telescopes such as LST and AtLAST.

DOI： 10.1117/12.2561885

ALMA twenty-six arcmin<sup>2</sup>survey of GOODS-S at one millimeter (ASAGAO) Open Access

Hatsukade B., Kohno K., Yamaguchi Y., Umehata H., Ao Y., Aretxaga I., Caputi K.I., Dunlop J.S., Egami E., Espada D., Fujimoto S., Hayatsu N., Hughes D.H., Ikarashi S., Iono D., Ivison R.J., Kawabe R., Kodama T., Lee M., Matsuda Y., Nakanishi K., Ohta K., Ouchi M., Rujopakarn W., Suzuki T., Tamura Y., Ueda Y., Wang T., Wang W.H., Wilson G.W., Yoshimura Y., Yun M.S.

Proceedings of the International Astronomical Union 頁： 239 - 240 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Proceedings of the International Astronomical Union

The ALMA twenty-six arcmin2 survey of GOODS-S at one millimeter (ASAGAO) is a deep (1σ ∼61μJy/beam) and wide area (26 arcmin2) survey on a contiguous field at 1.2 mm. By combining with archival data, we obtained a deeper map in the same region (1σ ∼30μJy/beam-1, synthesized beam size 0.59″ × 0.53″), providing the largest sample of sources (25 sources at 5σ, 45 sources at 4.5σ) among ALMA blank-field surveys. The median redshift of the 4.5σ sources is 2.4. The number counts shows that 52% of the extragalactic background light at 1.2 mm is resolved into discrete sources. We create IR luminosity functions (LFs) at z = 1-3, and constrain the faintest luminosity of the LF at 2 < z < 3. The LFs are consistent with previous results based on other ALMA and SCUBA-2 observations, which suggests a positive luminosity evolution and negative density evolution.

DOI： 10.1017/S1743921319009542

First light demonstration of the integrated superconducting spectrometer 査読有り

Endo Akira, Karatsu Kenichi, Tamura Yoichi, Oshima Tai, Taniguchi Akio, Takekoshi Tatsuya, Asayama Shin'ichiro, Bakx Tom J. L. C., Bosma Sjoerd, Bueno Juan, Chin Kah Wuy, Fujii Yasunori, Fujita Kazuyuki, Huiting Robert, Ikarashi Soh, Ishida Tsuyoshi, Ishii Shun, Kawabe Ryohei, Klapwijk Teun M., Kohno Kotaro, Kouchi Akira, Llombart Nuria, Maekawa Jun, Murugesan Vignesh, Nakatsubo Shunichi, Naruse Masato, Ohtawara Kazushige, Laguna Alejandro Pascual, Suzuki Junya, Suzuki Koyo, Thoen David J., Tsukagoshi Takashi, Ueda Tetsutaro, de Visser Pieter J., van der Werf Paul P., Yates Stephen J. C., Yoshimura Yuki, Yurduseven Ozan, Baselmans Jochem J. A.

NATURE ASTRONOMY 3 巻 ( 11 ) 頁： 989 - 996 2019年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Astronomy

Ultra-wideband, three-dimensional (3D) imaging spectrometry in the millimeter–submillimeter (mm–submm) band is an essential tool for uncovering the dust-enshrouded portion of the cosmic history of star formation and galaxy evolution1–3. However, it is challenging to scale up conventional coherent heterodyne receivers4 or free-space diffraction techniques5 to sufficient bandwidths (≥1 octave) and numbers of spatial pixels2,3 (>102). Here, we present the design and astronomical spectra of an intrinsically scalable, integrated superconducting spectrometer6, which covers 332–377 GHz with a spectral resolution of F/ΔF ~ 380. It combines the multiplexing advantage of microwave kinetic inductance detectors (MKIDs)7 with planar superconducting filters for dispersing the signal in a single, small superconducting integrated circuit. We demonstrate the two key applications for an instrument of this type: as an efficient redshift machine and as a fast multi-line spectral mapper of extended areas. The line detection sensitivity is in excellent agreement with the instrument design and laboratory performance, reaching the atmospheric foreground photon noise limit on-sky. The design can be scaled to bandwidths in excess of an octave, spectral resolution up to a few thousand and frequencies up to ~1.1 THz. The miniature chip footprint of a few cm2 allows for compact multi-pixel spectral imagers, which would enable spectroscopic direct imaging and large-volume spectroscopic surveys that are several orders of magnitude faster than what is currently possible1–3.

DOI： 10.1038/s41550-019-0850-8

Gas filaments of the cosmic web located around active galaxies in a protocluster 査読有り

Umehata H., Fumagalli M., Smail I., Matsuda Y., Swinbank A. M., Cantalupo S., Sykes C., Ivison R. J., Steidel C. C., Shapley A. E., Vernet J., Yamada T., Tamura Y., Kubo M., Nakanishi K., Kajisawa M., Hatsukade B., Kohno K.

SCIENCE 366 巻 ( 6461 ) 頁： 97 - + 2019年10月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Science

Cosmological simulations predict that the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve. However, the faintness of any emission from these filaments has limited tests of this prediction. We report the detection of rest-frame ultraviolet Lyman-a radiation from multiple filaments extending more than one megaparsec between galaxies within the SSA22 protocluster at a redshift of 3.1. Intense star formation and supermassive black-hole activity is occurring within the galaxies embedded in these structures, which are the likely sources of the elevated ionizing radiation powering the observed Lyman-a emission. Our observations map the gas in filamentary structures of the type thought to fuel the growth of galaxies and black holes in massive protoclusters.

DOI： 10.1126/science.aaw5949

Big Three Dragons: A z=7.15 Lyman-break galaxy detected in [O III] 88 μm, [C II] 158 μm, and dust continuum with ALMA 査読有り

Hashimoto Takuya, Inoue Akio K., Mawatari Ken, Tamura Yoichi, Matsuo Hiroshi, Furusawa Hisanori, Harikane Yuichi, Shibuya Takatoshi, Knudsen Kirsten K., Kohno Kotaro, Ono Yoshiaki, Zackrisson Erik, Okamoto Takashi, Kashikawa Nobunari, Oesch Pascal A., Ouchi Masami, Ota Kazuaki, Shimizu Ikkoh, Taniguchi Yoshiaki, Umehata Hideki, Watson Darach

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 71 巻 ( 4 ) 2019年8月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Publications of the Astronomical Society of Japan

We present new ALMA observations and physical properties of a Lyman break galaxy at z = 7.15. Our target, B14-65666, has a bright ultra-violet (UV) absolute magnitude, MUV ≈ -22.4, and has been spectroscopically identified in Lyα with a small rest-frame equivalent width of ≈4 Å. A previous Hubble Space TElescope (HST) image has shown that the target is composed of two spatially separated clumps in the rest-frame UV. With ALMA, we have newly detected spatially resolved [O iii] 88 μm, [C ii] 158 μm, and their underlying dust continuum emission. In the whole system of B14-65666, the [O iii] and [C ii] lines have consistent redshifts of 7.1520 ± 0.0003, and the [O iii] luminosity, (34.4 ± 4.1) × 108 Lo, is about three times higher than the [C ii] luminosity, (11.0 ± 1.4) × 108 Lo. With our two continuum flux densities, the dust temperature is constrained to be Td ≈ 50-60 K under the assumption of a dust emissivity index of βd = 2.0-1.5, leading to a large total infrared luminosity of LTIR ≈ 1 × 1012 Lo. Owing to our high spatial resolution data, we show that the [O iii] and [C ii] emission can be spatially decomposed into two clumps associated with the two rest-frame UV clumps whose spectra are kinematically separated by ≈200 km s-1. We also find these two clumps have comparable UV, infrared, [O iii], and [C ii] luminosities. Based on these results, we argue that B14-65666 is a starburst galaxy induced by a major merger. The merger interpretation is also supported by the large specific star formation rate (defined as the star formation rate per unit stellar mass), sSFR = 260+119-57:Gyr-1, inferred from our SED fitting. Probably, a strong UV radiation field caused by intense star formation contributes to its high dust temperature and the [O iii]-to-[C ii] luminosity ratio.

DOI： 10.1093/pasj/psz049

The onset of star formation 250 million years after the Big Bang 査読有り

Hashimoto Takuya, Laporte Nicolas, Mawatari Ken, Ellis Richard S., Inoue Akio K., Zackrisson Erik, Roberts-Borsani Guido, Zheng Wei, Tamura Yoichi, Bauer Franz E., Fletcher Thomas, Harikane Yuichi, Hatsukade Bunyo, Hayatsu Natsuki H., Matsuda Yuichi, Matsuo Hiroshi, Okamoto Takashi, Ouchi Masami, Pello Roser, Rydberg Claes-Erik, Shimizu Ikkoh, Taniguchi Yoshiaki, Umehata Hideki, Yoshida Naoki

NATURE 557 巻 ( 7705 ) 頁： 392 - + 2018年5月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature

A fundamental quest of modern astronomy is to locate the earliest galaxies and study how they influenced the intergalactic medium a few hundred million years after the Big Bang 1-3 . The abundance of star-forming galaxies is known to decline 4,5 from redshifts of about 6 to 10, but a key question is the extent of star formation at even earlier times, corresponding to the period when the first galaxies might have emerged. Here we report spectroscopic observations of MACS1149-JD1 6, a gravitationally lensed galaxy observed when the Universe was less than four per cent of its present age. We detect an emission line of doubly ionized oxygen at a redshift of 9.1096 ± 0.0006, with an uncertainty of one standard deviation. This precisely determined redshift indicates that the red rest-frame optical colour arises from a dominant stellar component that formed about 250 million years after the Big Bang, corresponding to a redshift of about 15. Our results indicate that it may be possible to detect such early episodes of star formation in similar galaxies with future telescopes.

DOI： 10.1038/s41586-018-0117-z

ADF22-WEB: A giant barred spiral starburst galaxy in the z=3.1 SSA22 protocluster core Open Access

Umehata, H; Steidel, CC; Smail, I; Swinbank, M; Monson, EB; Rosario, D; Lehmer, BD; Nakanishi, K; Kubo, M; Iono, D; Alexander, DM; Kohno, K; Tamura, Y; Ivison, RJ; Saito, T; Mitsuhashi, I; Huang, S; Matsuda, Y

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 2025年3月

RIOJA. Complex Dusty Starbursts in a Major Merger B14-65666 at <i>z</i>=7.15 Open Access

Sugahara, Y; Alvarez-Márquez, J; Hashimoto, T; Colina, L; Inoue, AK; Costantin, L; Fudamoto, Y; Mawatari, K; Ren, YW; Arribas, S; Bakx, TJLC; Blanco-Prieto, C; Ceverino, D; Gómez, AC; Hagimoto, M; Hashigaya, T; Marques-Chaves, R; Matsuo, H; Nakazato, Y; Pereira-Santaella, M; Tamura, Y; Usui, M; Yoshida, N

ASTROPHYSICAL JOURNAL 981 巻 ( 2 ) 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Astrophysical Journal

We present JWST NIRCam imaging of B14-65666 (“Big Three Dragons”), a bright Lyman-break galaxy system (MUV = −22.5 mag) at z = 7.15. The high angular resolution of NIRCam reveals the complex morphology of two galaxy components: galaxy E has a compact core (E-core), surrounded by diffuse, extended, rest-frame optical emission, which is likely to be tidal tails; and galaxy W has a clumpy and elongated morphology with a blue UV slope (βUV = −2.2 ± 0.1). The flux excess, F356W − F444W, peaks at the E-core ( 1.0 5 − 0.09 + 0.08 mag), tracing the presence of strong [O iii] λλ4960,5008 emission. Atacama Large Millimeter/submillimeter Array archival data show that the bluer galaxy W is brighter in dust continua than the redder galaxy E, while the tails are bright in [O iii] 88 μm. The UV/optical and submillimeter spectral energy distribution (SED) fitting confirms that B14-65666 is a major merger in a starburst phase as derived from the stellar mass ratio (3:1 to 2:1) and the star formation rate, ≃1 dex higher than the star formation main sequence at the same redshift. Galaxy E is a dusty (AV = 1.2 ± 0.1 mag) starburst with a possible high dust temperature (≥63-68 K). Galaxy W would have a low dust temperature (≤27-33 K) or patchy stellar-and-dust geometry, as suggested by the IR excess and βUV diagram. The high optical-to-far-IR [O iii] line ratio of the E-core shows its lower gas-phase metallicity (≃0.2-0.4 Z⊙) than galaxy W. These results agree with a scenario where major mergers disturb morphology and induce nuclear dusty starbursts triggered by less-enriched inflows. B14-65666 shows a picture of complex stellar buildup processes during major mergers in the epoch of reionization.

DOI： 10.3847/1538-4357/adb02a

Large Molecular and Dust Reservoir of a Gravitationally Lensed Submillimeter Galaxy behind the Lupus I Molecular Cloud Open Access

Tamura, Y; Taniguchi, A; Bakx, TJLC; De Gregorio-Monsalvo, I; Hagimoto, M; Ikarashi, S; Kawabe, R; Kohno, K; Nakanishi, K; Takekoshi, T; Shimajiri, Y; Tsukagoshi, T; Hatsukade, B; Iono, D; Matsuhara, H; Saigo, K; Saito, M

ASTROPHYSICAL JOURNAL 981 巻 ( 1 ) 2025年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Astrophysical Journal

We report the Australian Telescope Compact Array and Nobeyama 45 m telescope detection of a remarkably bright (S1.1mm = 44 mJy) submillimeter galaxy MM J154506.4−344318 in emission lines at 48.5 and 97.0 GHz, respectively. We also identify part of an emission line at ≈218.3 GHz using the Atacama Large Millimeter/submillimeter Array (ALMA). Together with photometric redshift estimates and the ratio between the line and infrared luminosities, we conclude that the emission lines are most likely to be the J = 2-1, 4-3, and 9-8 transitions of 12CO at redshift z = 3.753 ± 0.001. ALMA 1.3 mm continuum imaging reveals an arc and a spot separated by an angular distance of 1 . ″ 6 , indicative of a strongly lensed dusty star-forming galaxy with respective molecular and dust masses of log M mol / M ⊙ ≈ 11.5 and log M dust / M ⊙ ≈ 9.4 after being corrected for ≈6.6× gravitational magnification. The inferred dust-to-gas mass ratio is found to be high (≈0.0083) among coeval dusty star-forming galaxies, implying the presence of a massive, chemically enriched reservoir of cool interstellar medium at z ≈ 4, or 1.6 Gyr after the Big Bang.

DOI： 10.3847/1538-4357/adb1b9

JWST, ALMA, and Keck Spectroscopic Constraints on the UV Luminosity Functions at <i>z</i> ∼ 7-14: Clumpiness and Compactness of the Brightest Galaxies in the Early Universe Open Access

Harikane, Y; Inoue, AK; Ellis, RS; Ouchi, M; Nakazato, Y; Yoshida, N; Ono, Y; Sun, FW; Sato, RA; Ferrami, G; Fujimoto, S; Kashikawa, N; Mcleod, DJ; Pérez-González, PG; Sawicki, M; Sugahara, Y; Xu, Y; Yamanaka, S; Carnall, AC; Cullen, F; Dunlop, JS; Egami, E; Grogin, N; Isobe, Y; Koekemoer, AM; Laporte, N; Lee, CH; Magee, D; Matsuo, H; Matsuoka, Y; Mawatari, K; Nakajima, K; Nakane, M; Tamura, Y; Umeda, H; Yanagisawa, H

ASTROPHYSICAL JOURNAL 980 巻 ( 1 ) 2025年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Astrophysical Journal

We present the number densities and physical properties of the bright galaxies spectroscopically confirmed at z ∼ 7-14. Our sample is composed of 60 galaxies at zspec ∼ 7-14, including recently confirmed galaxies at zspec = 12.34-14.18 with JWST, as well as new confirmations at zspec = 6.583-7.643 with −24 < MUV < −21 mag using ALMA and Keck. Our JWST/NIRSpec observations have also revealed that very bright galaxy candidates at z ∼ 10-13 identified from ground-based telescope images before JWST are passive galaxies at z ∼ 3-4, emphasizing the necessity of strict screening and spectroscopy in the selection of the brightest galaxies at z > 10. The UV luminosity functions derived from these spectroscopic results are consistent with a double power-law function, showing tensions with theoretical models at the bright end. To understand the origin of the overabundance of bright galaxies, we investigate their morphologies using JWST/NIRCam high-resolution images obtained in various surveys, including PRIMER and COSMOS-Web. We find that ∼70% of the bright galaxies at z ∼ 7 exhibit clumpy morphologies with multiple subcomponents, suggesting merger-induced starburst activity, which is consistent with SED fitting results showing bursty star formation histories. At z ≳ 10, bright galaxies are classified into two types of galaxies: extended ones with weak high-ionization emission lines, and compact ones with strong high-ionization lines including N iv]λ1486, indicating that at least two different processes (e.g., merger-induced starburst and compact star formation/AGN) are shaping the physical properties of the brightest galaxies at z ≳ 10 and are responsible for their overabundance.

DOI： 10.3847/1538-4357/ad9b2c

Detection of the [O i] 63 μm emission line from the z=6.04 quasar J2054-0005 Open Access

Ishii, N; Hashimoto, T; Ferkinhoff, C; Rybak, M; Inoue, AK; Michiyama, T; Donevski, D; Fujimoto, S; Salak, D; Kuno, N; Matsuo, H; Mawatari, K; Tamura, Y; Izumi, T; Nagao, T; Nakazato, Y; Osone, W; Sugahara, Y; Usui, M; Wakasugi, K; Yajima, H; Bakx, TJLC; Fudamoto, Y; Meyer, RA; Walter, F; Yoshida, N

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 77 巻 ( 1 ) 頁： 139 - 148 2024年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Publications of the Astronomical Society of Japan

We report the highest-redshift detection of [O i] 63 m from a luminous quasar, J20540005, at based on the Atacama Large Millimeter/sub-millimeter Array (ALMA) Band 9 observations. The [O i] 63 m line luminosity is, corresponding to the [O i] 63 m-to-far-infrared luminosity ratio of 6.7, which is consistent with the value obtained in the local Universe. Remarkably, [O i] 63 m is as bright as [C ii] 158 m, resulting in the [O i]-to-[C ii] line luminosity ratio of. Based on a careful comparison of the luminosity ratios of [O i] 63 m, [C ii] 158 m, and dust continuum emission to models of photodissociation regions, we find that J20540005 has a gas density and an incident far-ultraviolet radiation field of, showing that [O i] 63 m serves as an important coolant of the dense and warm gas in J20540005. A close examination of the [O i] and [C ii] line profiles suggests that the [O i] line may be partially self-absorbed; however, deeper observations are needed to verify this conclusion. Regardless, the gas density and incident radiation field are in broad agreement with the values obtained in nearby star-forming galaxies and objects with [O i] 63 m observations at -3 with the Herschel Space Observatory. These results demonstrate the power of ALMA high-frequency observations targeting [O i] 63 m to examine the properties of photodissociation regions in high-redshift galaxies.

DOI： 10.1093/pasj/psae105

A novel high-z submm galaxy efficient line survey in ALMA Bands 3 through 8-an ANGELS pilot Open Access

Bakx, TJLC; Amvrosiadis, A; Bendo, GJ; Algera, HSB; Serjeant, S; Bonavera, L; Borsato, E; Chen, X; Cox, P; Gonzalez-Nuevo, J; Hagimoto, M; Harrington, KC; Ivison, RJ; Kamieneski, P; Marchetti, L; Riechers, DA; Tsukui, T; van der Werf, PP; Yang, C; Zavala, JA; Andreani, P; Berta, S; Cooray, AR; De Zotti, G; Eales, S; Ikeda, R; Knudsen, KK; Mitsuhashi, ; Negrello, M; Neri, R; Omont, A; Scott, D; Tamura, Y; Temi, P; Urquhart, SA

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 535 巻 ( 2 ) 頁： 1533 - 1574 2024年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Monthly Notices of the Royal Astronomical Society

We use the Atacama Large sub/Millimetre Array (ALMA) to efficiently observe spectral lines across Bands 3, 4, 5, 6, 7, and 8 at high-resolution (0.5–0.1 arcsec) for 16 bright southern Herschel sources at 1.5 < z < 4.2. With only six and a half hours of observations, we reveal 66 spectral lines in 17 galaxies. These observations detect emission from CO (3−2) to CO(18−17), as well as atomic ([C I](1−0), (2−1), [O I] 145 μm and [N II] 205 μm) lines. Additional molecular lines are seen in emission (H2O and H2O+) and absorption (OH+ and CH+). The morphologies based on dust continuum ranges from extended sources to strong lensed galaxies with magnifications between 2 and 30. CO line transitions indicate a diverse set of excitation conditions with a fraction of the sources (∼ 35 per cent) showcasing dense, warm gas. The resolved gas to star formation surface densities vary strongly per source, and suggest that the observed diversity of dusty star-forming galaxies could be a combination of lensed, compact dusty starbursts and extended, potentially merging galaxies. The predicted gas depletion time-scales are consistent with 100 Myr to 1 Gyr, but require efficient fuelling from the extended gas reservoirs onto the more central starbursts, in line with the Doppler-shifted absorption lines that indicate inflowing gas for two out of six sources. This pilot paper explores a successful new method of observing spectral lines in large samples of galaxies, supports future studies of larger samples, and finds that the efficiency of this new observational method will be further improved with the planned ALMA Wideband Sensitivity Upgrade.

DOI： 10.1093/mnras/stae2409

JWST/NIRSpec spectroscopy of intermediate-mass quiescent galaxies at z ∼ 3-4 Open Access

Sato, RA; Inoue, AK; Harikane, Y; Shimakawa, R; Sugahara, Y; Tamura, Y; Hashimoto, T; Ito, K; Yamanaka, S; Mawatari, K; Fudamoto, Y; Ren, YW

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 534 巻 ( 4 ) 頁： 3552 - 3564 2024年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Monthly Notices of the Royal Astronomical Society

We present the analysis of three intermediate-mass quiescent galaxies (QGs) with stellar masses of ∼1010 M at redshifts z ∼ 3–4 using NIRSpec low-resolution spectroscopy. Utilizing the spectral energy distribution fitting code BAGPIPES, we confirm these target galaxies are consistent with quiescent population, with their specific star formation rates falling below 2 dex the star-forming main sequence at the same redshifts. Additionally, we identify these QGs to be less massive than those discovered in previous works, particularly prior to the JWST era. Two of our target galaxies exhibit the potentially blended H α + [N II] emission line within their spectra with signal-to-noise ratio >5. We discuss whether this feature comes from an active galactic nucleus (AGN) or star formation, although future high-resolution spectroscopy is required to reach a conclusion. One of the target galaxies is covered by JWST/NIRCam imaging of the Public Release IMaging for Extragalactic Research survey. Using the 2D profile fitting code GALFIT, we examine its morphology, revealing a disc-like profile with a Sérsic index of n = 1.1 ± 0.1. On the size–mass relation, we find a potential distinction between less massive (log10 (M∗/M) < 10.3) and massive (log10 (M∗/M) > 10.3) QGs in their evolutionary pathways. The derived quenching time-scales for our targets are less than 1 Gyr. This may result from these galaxies being quenched by AGN feedback, supporting the AGN scenario of the emission line features.

DOI： 10.1093/mnras/stae2300

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