Papers - Tanaka, Kunihiko

Shock-induced HCNH+ abundance enhancement in the heart of the starburst galaxy NGC 253 unveiled by ALCHEMI

Y. Gong, C. Henkel, C. T. Bop, J. G. Mangum, E. Behrens, F. J. Du, S. B. Zhang, S. Martin, K. M. Menten, N. Harada, M. Bouvier, X. D. Tang, K. Tanaka, S. Viti, Y. T. Yan, W. Yang, R. Q. Mao, D. H. Quan

Astronomy and Astrophysics  2025

Joint Work, Accepted

Spatially-resolved spectro-photometric SED Modeling of NGC 253's Central Molecular Zone I. Studying the star formation in extragalactic giant molecular clouds

Humire, Pedro K. ; Dey, Subhrata ; Ronconi, Tommaso ; Sasse, Victor H. ; Cid Fernandes, Roberto ; Martín, Sergio ; Donevski, Darko search by orcid ; Małek, Katarzyna ; Fernández-Ontiveros, Juan A. ; Song, Yiqing ; Hamed, Mahmoud ; Mangum, Jeffrey G. ; Henkel, Christian ; Rivilla, Víctor M. ; Colzi, Laura ; Harada, N. ; Demarco, Ricardo ; Goyal, Arti ; Meier, David S. ; Panda, Swayamtrupta ; Krabbe, Ângela C. ; Yan, Yaoting ; Lopes, Amanda R. search by orcid ; Sakamoto, K. ; Muller, S. ; Tanaka, K. ; Yoshimura, Y. ; Nakanishi, K. ; Kanaan, Antonio ; Ribeiro, Tiago ; Schoenell, William ; Mendes de Oliveira, Claudia

Astronomy and Astrophysics  2025

Research paper (scientific journal), Joint Work, Accepted

Neural Network Constraints on the Cosmic-Ray Ionization Rate and Other Physical Conditions in NGC 253 with ALCHEMI Measurements of HCN and HNC

Neural Network Constraints on the Cosmic-Ray Ionization Rate and Other Physical Conditions in NGC 253 with ALCHEMI Measurements of HCN and HNC

977   38 2024.12

Research paper (scientific journal), Joint Work, Accepted

Bright-rimmed clouds in IC 1396: I. Dynamics

Okada Yoko, Kabanovic Slawa, Güsten Rolf, Ossenkopf-Okada Volker, Schneider Nicola, Simon Robert, Buchbender Christof, Higgins Ronan, Yanitski Craig, Röllig Markus, Stutzki Jürgen, Ishihara Daisuke, Tanaka Kunihiko, Chambers Edward, Honingh Netty, Justen Matthias, Riquelme Denise

Astronomy and Astrophysics 690 ( 45 )  2024.10

Research paper (scientific journal), Joint Work, Accepted

Molecular isotopologue measurements toward super star clusters and the relation to their ages in NGC253 with ALCHEMI

Butterworth, J. , Viti, S. , Van der Werf, P. P. , Mangum, J. G. , Martín, S. , Harada, N. , Emig, K. L. , Muller, S. , Sakamoto, K. , Yoshimura, Y. , Tanaka, K. , Herrero-Illana, R. , Colzi, L. , Rivilla, V. M. , Huang, K. Y. , Bouvier, M. , Behrens, E. , Henkel, C. , Yan, Y. T. , Meier, D. S. , Zhou, D.

Astronomy and Astrophysics (EDP Science)  686   31 2024.06

Research paper (scientific journal), Joint Work, Accepted

Physical Properties of the Southwest Outflow Streamer in the Starburst Galaxy NGC 253 with ALCHEMI

Bao, Min ; Harada, Nanase ; Kohno, Kotaro ; Yoshimura, Yuki ; Egusa, Fumi ; Nishimura, Yuri ; Tanaka, Kunihiko ; Nakanishi, Kouichiro ; Martín, Sergio ; Mangum, Jeffrey G. ; Sakamoto, Kazushi ; Muller, Sébastien ; Bouvier, Mathilde ; Colzi, Laura search by orcid ; Emig, Kimberly L. ; Meier, David S. ; Henkel, Christian ; Humire, Pedro ; Huang, Ko-Yun ; Rivilla, Víctor M. ; van der Werf, Paul ; Viti, Serena

Astronomy & Astrophysics (EDP Science)  687   43 2024.05

Research paper (scientific journal), Joint Work, Accepted

The ALCHEMI atlas: principal component analysis reveals starburst evolution in NGC 253

Harada, Nanase ; Meier, David S. ; Martín, Sergio ; Muller, Sebastien ; Sakamoto, Kazushi ; Saito, Toshiki ; Gorski, Mark D. ; Henkel, Christian ; Tanaka, Kunihiko ; Mangum, Jeffrey G. ; Aalto, Susanne ; Aladro, Rebeca ; Bouvier, Mathilde ; Colzi, Laura search by orcid ; Emig, Kimberly L. ; Herrero-Illana, Rubén ; Huang, Ko-Yun ; Kohno, Kotaro ; König, Sabine ; Nakanishi, Kouichiro ; Nishimura, Yuri ; Takano, Shuro ; Rivilla, Víctor M. ; Viti, Serena ; Watanabe, Yoshimasa ; van der Werf, Paul P. , Yoshimura, Yuki

The Astrophysical Journal Supplement Series (IOP publishing)  271   38 2024.04

Research paper (scientific journal), Joint Work, Accepted

Volume Density Structure of the NGC253 CMZ through ALCHEMI Excitation Analysis

Tanaka, Kunihiko ; Mangum, Jeffrey G. ; Viti, Serena ; Martin, Sergio ; Harada, Nanase ; Sakamoto, Kazushi ; Muller, Sebastien ; Yoshimura, Yuki ; Nakanishi, Kouichiro ; Herrero Illana, Ruben ; Emig, Kimberly L. ; Muhle, S. ; Kaneko, Hiroyuki ; Tosaki, Tomoka ; Behrens, Erica ; Rivilla, Victor M. ; Colzi, Laura ; Nishimura, Yuri ; Humire, P. K. ; Bouvier, Mathilde ; Huang, Ko-Yun ; Butterworth, Joshua ; Meier, David S. ; van der Werf, Paul P.

The Astrophysical Journal (IOP publishing)  916   18 2024.01

Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted

FINER: Far-Infrared Nebular Emission Receiver for the Large Millimeter Telescope

Tamura, Yoichi ; Sakai, Takeshi ; Kawabe, Ryohei ; Kojima, Takafumi ; Taniguchi, Akio ; Takekoshi, Tatsuya ; Kang, Haoran ; Shan, Wenlei ; Hagimoto, Masato ; Okauchi, Norika ; Tetsuka, Airi ; Inoue, Akio K. ; Kohno, Kotaro ; Tanaka, Kunihiko ; Bakx, Tom J. L. C. ; Fudamoto, Yoshinobu ; Fujita, Kazuyuki ; Harikane, Yuichi ; Hashimoto, Takuya ; Hatsukade, Bunyo ; Hughes, David H. ; Iino, Takahiro ; Kimura, Yuki ; Maezawa, Hiroyuki ; Matsuda, Yuichi ; Mawatari, Ken ; Nakajima, Taku ; Nakatsubo, Shunichi ; Oshima, Tai ; Sagawa, Hideo ; Schloerb, F. Peter ; Takahashi, Shigeru ; Taniguchi, Kotomi ; Tsujita, Akiyoshi ; Umehata, Hideki ; Yonetsu, Teppei ; Yun, Min S.

Proceedings paper presented in SPIE Astronomical Telescope and Instrumentation 2024  2024

A 10.24-GHz-wide digital spectrometer array system for LMT-FINER: system design and laboratory performance verification

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

Proceedings paper presented in SPIE Astronomical Telescope and Instrumentation 2024  2024

An ALCHEMI inspection of sulphur-bearing species towards the central molecular zone of NGC 253

Bouvier, M. ; Viti, S. ; Behrens, E. ; Butterworth, J. ; Huang, K. -Y. ; Mangum, J. G. ; Harada, N. ; Martín, S. ; Rivilla, V. M. ; Muller, S. ; Sakamoto, K. ; Yoshimura, Y. ; Tanaka, K. ; Nakanishi, K. ; Herrero-Illana, R. ; Colzi, L. ; Gorski, M. D. ; Henkel, C. ; Humire, P. K. ; Meier, D. S. ; van der Werf, P. P. ; Yan, Y. T.

Astronomy & Astrophysics (EDP Science)   2024

Research paper (scientific journal), Joint Work, Accepted

Distributions of the Density and Kinetic Temperature of the Molecular Gas in the Central Region of NGC 613 Using Hierarchical Bayesian Inference

Kaneko, Hiroyuki; Tosaki, Tomoka; Tanaka, Kunihiko ; Miyamoto, Yusuke

The Astrophysical Journal (IOP publishing)  953   139 2023.08

Research paper (scientific journal), Joint Work, Accepted

Reconstructing the shock history in the CMZ of NGC 253 with ALCHEMI

Huang, K. -Y. ; Viti, S. ; Holdship, J. ; Mangum, J. G. ; Martín, S. ; Harada, N. ; Muller, S. ; Sakamoto, K. ; Tanaka, K. ; Yoshimura, Y. ; Herrero-Illana, R. ; Meier, D. S. ; Behrens, E. ; van der Werf, P. P. ; Henkel, C. ; García-Burillo, S. ; Rivilla, V. M. ; Emig, K. L. ; Colzi, L. search by orcid ; Humire, P. K. ; ...

 2023.03

Research paper (scientific journal), Joint Work, Accepted

Tracing Interstellar Heating: An ALCHEMI Measurement of the HCN Isomers in NGC 253

Behrens, Erica ; Mangum, Jeffrey G. ; Holdship, Jonathan ; Viti, Serena ; Harada, Nanase ; Martin, Sergio ; Sakamoto, Kazushi ; Muller, Sebastien ; Tanaka, Kunihiko ; Nakanishi, Kouichiro ; Herrero-Illana, Ruben ; Yoshimura, Yuki ; Aladro, Rebeca ; Colzi, Laura ; Emig, Kimberly L. ; Henkel, Christian ; Huang, Ko-Yun ; Humire, P. K. ; Meier, David S. ; Rivilla, Victor M. Abstract

939   119 2022.11

Research paper (scientific journal), Accepted

ALCHEMI finds a "shocking" carbon footprint in the starburst galaxy NGC~253

Harada, Nanase ; Martin, Sergio ; Mangum, Jeff ; Sakamoto, Kazushi ; Muller, Sebastian ; Rivilla, Victor ; Henkel, Christian ; Meier, David ; Colzi, Laura ; Yamagishi, Mitsuyoshi ; Tanaka, Kunihiko ; Nakanishi, Kouichiro ; Herrero-Illana, Ruben ; Yoshimura, Yuki ; Humire, Pedro ; Aladro, Rebeca ; van der Werf, Paul ; Emig, Kim

938   80 2022.10

Research paper (scientific journal), Joint Work, Accepted

Methanol masers in NGC 253 with ALCHEMI

Humire, P. K. ; Henkel, C. ; Hernández-Gómez, A. ; Martín, S. ; Mangum, J. ; Harada, N. ; Muller, S. ; Sakamoto, K. ; Tanaka, K. ; Yoshimura, Y. ; Nakanishi, K. ; Mühle, S. ; Herrero-Illana, R. ; Meier, D. S. ; Caux, E. ; Aladro, R. ; Mauersberger, R. ; Viti, S. ; Colzi, L. ; Rivilla, V. M. ;

Astronomy and Astrophysics (Astronomy and Astrophysics)  663   33 2022.07

Research paper (scientific journal), Accepted,  ISSN  00046361

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Context. Methanol masers of Class I (collisionally pumped) and Class II (radiatively pumped) have been studied in great detail in our Galaxy in a variety of astrophysical environments such as shocks and star-forming regions and are they are helpful to analyze the properties of the dense interstellar medium. However, the study of methanol masers in external galaxies is still in its infancy. Aims. Our main goal is to search for methanol masers in the central molecular zone (CMZ; inner 500 pc) of the nearby starburst galaxy NGC253. Methods. Covering a frequency range between 84 and 373 GHz (λ = 3.6-0.8 mm) at high angular (1."6 ∼ 27 pc) and spectral (∼8-9 km s-1) resolution with ALCHEMI (ALMA Comprehensive High-resolution Extragalactic Molecular Inventory), we have probed dierent regions across the CMZ of NGC253. In order to look for methanol maser candidates, we employed the rotation diagram method and a set of radiative transfer models. Results.We detect for the first time masers above 84 GHz in NGC253, covering an ample portion of the J-1 (J-1)0-E line series (at 84, 132, 229, and 278 GHz) and the J0 (J-1)1 A series (at 95, 146, and 198 GHz). This confirms the presence of the Class I maser line at 84 GHz, which was already reported, but now being detected in more than one location. For the J-1 (J-1)0-E line series, we observe a lack of Class I maser candidates in the central star-forming disk. Conclusions. The physical conditions for maser excitation in the J-1 (J-1)0-E line series can be weak shocks and cloud-cloud collisions as suggested by shock tracers (SiO and HNCO) in bi-symmetric shock regions located in the outskirts of the CMZ. On the other hand, the presence of photodissociation regions due to a high star-formation rate would be needed to explain the lack of Class I masers in the very central regions.

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Energizing Star Formation: The Cosmic-Ray Ionization Rate in NGC 253 Derived from ALCHEMI Measurements of H<inf>3</inf>O⁺and SO

Holdship J., Mangum J.G., Viti S., Behrens E., Harada N., Martín S., Sakamoto K., Muller S., Tanaka K., Nakanishi K., Herrero-Illana R., Yoshimura Y., Aladro R., Colzi L., Emig K.L., Henkel C., Nishimura Y., Rivilla V.M., Van Der Werf P.P.

Astrophysical Journal (Astrophysical Journal)  931 ( 2 )  2022.06

Research paper (scientific journal), Accepted,  ISSN  0004637X

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The cosmic-ray ionization rate (CRIR) is a key parameter in understanding the physical and chemical processes in the interstellar medium. Cosmic rays are a significant source of energy in star formation regions, impacting the physical and chemical processes that drive the formation of stars. Previous studies of the circum-molecular zone of the starburst galaxy NGC 253 have found evidence for a high CRIR value: 103-106 times the average CRIR within the Milky Way. This is a broad constraint, and one goal of this study is to determine this value with much higher precision. We exploit ALMA observations toward the central molecular zone of NGC 253 to measure the CRIR. We first demonstrate that the abundance ratio of H3O+ and SO is strongly sensitive to the CRIR. We then combine chemical and radiative transfer models with nested sampling to infer the gas properties and CRIR of several star-forming regions in NGC 253 from emission from their transitions. We find that each of the four regions modeled has a CRIR in the range (1-80) × 10-14 s-1 and that this result adequately fits the abundances of other species that are believed to be sensitive to cosmic rays, including C2H, HCO+, HOC+, and CO. From shock and photon-dominated/X-ray dominated region models, we further find that neither UV-/X-ray-driven nor shock-dominated chemistry is a viable single alternative as none of these processes can adequately fit the abundances of all of these species.

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Energizing Star Formation: The Cosmic Ray Ionization Rate in NGC 253 Derived From ALCHEMI Measurements of H$_3$O$^+$ and SO

Holdship, Jonathan ; Mangum, Jeffrey G. ; Viti, Serena ; Behrens, Erica ; Harada, Nanase ; Martín, Sergio ; Sakamoto, Kazushi ; Muller, Sebastien ; Tanaka, Kunihiko ; Nakanishi, Kouichiro ; Herrero-Illana, Rubén ; Yoshimura, Yuki ; Aladro, Rebeca ; Colzi, Laura ; Emig, Kimberly L. ; Henkel, Christian ; Nishimura, Yuri ; Rivilla, Víctor M. ; van der Werf, Paul P.

The Astrophysical Journal 931   89 2022.06

Research paper (scientific journal), Joint Work, Accepted

First extragalactic detection of a phosphorus-bearing molecule with ALCHEMI: Phosphorus nitride (PN)

Haasler, D. search by orcid ; Rivilla, V. M. ; Martín, S. ; Holdship, J. ; Viti, S. ; Harada, N. ; Mangum, J. ; Sakamoto, K. ; Muller, S. ; Tanaka, K. ; Yoshimura, Y. ; Nakanishi, K. ; Colzi, L. search by orcid ; Hunt, L. search by orcid ; Emig, K. L. ; Aladro, R. ; Humire, P. ; Henkel, C. ; van der Werf, P.

Astronomy & Astrophysics (Astronomy and Astrophysics)  659   158 2022.03

Research paper (scientific journal), Joint Work, Accepted,  ISSN  00046361

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Context. Phosphorus (P) is a crucial element for life given its central role in several biomolecules. P-bearing molecules have been discovered in different regions of the Milky Way, but not yet towards an extragalactic environment. Aims. We searched for P-bearing molecules outside the Milky Way towards the nearby starburst Galaxy NGC 253. Methods. Using observations from the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) project, we used the MAdrid Data CUBe Analysis package to model the emission of P-bearing molecules assuming local thermodynamic equilibrium (LTE) conditions. We also performed a non-LTE analysis using SpectralRadex. Results. We report the detection of a P-bearing molecule, phosphorus nitride (PN), for the first time in an extragalactic environment, towards two giant molecular clouds (GMCs) of NGC 253. The LTE analysis yields total PN beam-averaged column densities N = (1.20 ± 0.09) - 1013 cm-2 and N = (6.5 ± 1.6) - 1012 cm-2, which translate into abundances with respect to H2 of = (8.0 ± 1.0) - 10-12 and = (4.4 ± 1.2) - 10-12. We derived a low excitation temperature of Tex = (4.4 ± 1.3) K towards the GMC with the brightest PN emission, which indicates that PN is sub-thermally excited. The non-LTE analysis results in column densities consistent with the LTE values. We also searched for other P-bearing molecules (PO, PH3, CP, and CCP), and upper limits were derived. The derived PO/PN ratios are < 1.3 and < 1.7. The abundance ratio between PN and the shock-tracer SiO derived towards NGC 253 follows the same trend previously found towards Galactic sources. Conclusions. Comparison of the observations with chemical models indicates that the derived molecular abundances of PN in NGC 253 can be explained by shock-driven chemistry followed by cosmic-ray-driven photochemistry.

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Starburst Energy Feedback Seen through HCO⁺/HOC⁺Emission in NGC 253 from ALCHEMI

Harada N., Martín S., Mangum J.G., Sakamoto K., Muller S., Tanaka K., Nakanishi K., Herrero-Illana R., Yoshimura Y., Mühle S., Aladro R., Colzi L., Rivilla V.M., Aalto S., Behrens E., Henkel C., Holdship J., Humire P.K., Meier D.S., Nishimura Y., Van Der Werf P.P., Viti S.

Astrophysical Journal (Astrophysical Journal)  923 ( 1 )  2021.12

ISSN  0004637X

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Molecular abundances are sensitive to the UV photon flux and cosmic-ray ionization rate. In starburst environments, the effects of high-energy photons and particles are expected to be stronger. We examine these astrochemical signatures through multiple transitions of HCO+ and its metastable isomer HOC+ in the center of the starburst galaxy NGC 253 using data from the Atacama Large Millimeter/submillimeter Array large program ALMA Comprehensive High-resolution Extragalactic Molecular inventory. The distribution of the HOC+(1-0) integrated intensity shows its association with "superbubbles,"cavities created either by supernovae or expanding H ii regions. The observed HCO+/HOC+ abundance ratios are ∼10-150, and the fractional abundance of HOC+ relative to H2 is ∼1.5 × 10-11-6 × 10-10, which implies that the HOC+ abundance in the center of NGC 253 is significantly higher than in quiescent spiral arm dark clouds in the Galaxy and the Galactic center clouds. Comparison with chemical models implies either an interstellar radiation field of G 0 ⪆ 103 if the maximum visual extinction is ⪆5, or a cosmic-ray ionization rate of ζ ⪆ 10-14 s-1 (3-4 orders of magnitude higher than that within clouds in the Galactic spiral arms) to reproduce the observed results. From the difference in formation routes of HOC+, we propose that a low-excitation line of HOC+ traces cosmic-ray dominated regions, while high-excitation lines trace photodissociation regions. Our results suggest that the interstellar medium in the center of NGC 253 is significantly affected by energy input from UV photons and cosmic rays, sources of energy feedback.

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ALCHEMI, an ALMA Comprehensive High-resolution Extragalactic Molecular Inventory: Survey presentation and first results from the ACA array

Martín S., Mangum J.G., Harada N., Costagliola F., Sakamoto K., Muller S., Aladro R., Tanaka K., Yoshimura Y., Nakanishi K., Herrero-Illana R., Mühle S., Aalto S., Behrens E., Colzi L., Emig K.L., Fuller G.A., García-Burillo S., Greve T.R., Henkel C., Holdship J., Humire P., Hunt L., Izumi T., Kohno K., König S., Meier D.S., Nakajima T., Nishimura Y., Padovani M., Rivilla V.M., Takano S., Van Der Werf P.P., Viti S., Yan Y.T.

Astronomy and Astrophysics (Astronomy and Astrophysics)  656 2021.12

Research paper (scientific journal), Accepted,  ISSN  00046361

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Context. The interstellar medium is the locus of physical processes affecting the evolution of galaxies which drive or are the result of star formation activity, supermassive black hole growth, and feedback. The resulting physical conditions determine the observable chemical abundances that can be explored through molecular emission observations at millimeter and submillimeter wavelengths. Aims. Our goal is to unveiling the molecular richness of the central region of the prototypical nearby starburst galaxy NGC 253 at an unprecedented combination of sensitivity, spatial resolution, and frequency coverage. Methods. We used the Atacama Large Millimeter/submillimeter Array (ALMA), covering a nearly contiguous 289 GHz frequency range between 84.2 and 373.2 GHz, to image the continuum and spectral line emission at 1.6″(∼28 pc) resolution down to a sensitivity of 30 - 50 mK. This article describes the ALMA Comprehensive High-resolution Extragalactic Molecular Inventory (ALCHEMI) large program. We focus on the analysis of the spectra extracted from the 15″ (∼255 pc) resolution ALMA Compact Array data. Results. We modeled the molecular emission assuming local thermodynamic equilibrium with 78 species being detected. Additionally, multiple hydrogen and helium recombination lines are identified. Spectral lines contribute 5 to 36% of the total emission in frequency bins of 50 GHz. We report the first extragalactic detections of C2H5OH, HOCN, HC3HO, and several rare isotopologues. Isotopic ratios of carbon, oxygen, sulfur, nitrogen, and silicon were measured with multiple species. Concluison. Infrared pumped vibrationaly excited HCN, HNC, and HC3N emission, originating in massive star formation locations, is clearly detected at low resolution, while we do not detect it for HCO+. We suggest high temperature conditions in these regions driving a seemingly "carbon-rich"chemistry which may also explain the observed high abundance of organic species close to those in Galactic hot cores. The Lvib/LIR ratio was used as a proxy to estimate a 3% contribution from the proto super star cluster to the global infrared emission. Measured isotopic ratios with high dipole moment species agree with those within the central kiloparsec of the Galaxy, while those derived from 13C/18O are a factor of five larger, confirming the existence of multiple interstellar medium components within NGC 253 with different degrees of nucleosynthesis enrichment. The ALCHEMI data set provides a unique template for studies of star-forming galaxies in the early Universe.

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Starburst Energy Feedback Seen Through HCO$^+$/HOC$^+$ Emission in NGC 253 from ALCHEMI

Nanase Harada, Sergio Martín, Jeffrey G. Mangum, Kazushi Sakamoto, Sebastien Muller, Kunihiko Tanaka, Kouichiro Nakanishi, Rubén Herrero-Illana, Yuki Yoshimura, Stefanie Mühle, Rebeca Aladro, Laura Colzi, Víctor M. Rivilla, Susanne Aalto, Erica Behrens, Christian Henkel, Jonathan Holdship, P. K. Humire, David S. Meier, Yuri Nishimura, Paul P. van der Werf, Serena Viti

Astrophysical Journal 923   24 2021.12

Joint Work, Accepted

Clustered Star Formation in the Center of NGC 253 Contributes to Driving the Ionized Nuclear Wind

Mills E.A.C., Gorski M., Emig K.L., Bolatto A.D., Levy R.C., Leroy A.K., Ginsburg A., Henshaw J.D., Zschaechner L.K., Veilleux S., Tanaka K., Meier D.S., Walter F., Krieger N., Ott J.

Astrophysical Journal (Astrophysical Journal)  919 ( 2 )  2021.10

Research paper (scientific journal), Accepted,  ISSN  0004637X

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We present new 3 mm observations of the ionized gas toward the nuclear starburst in the nearby (D ∼ 3.5 Mpc) galaxy NGC 253. With ALMA, we detect emission from the H40α and He40α lines in the central 200 pc of this galaxy on spatial scales of ∼4 pc. The recombination line emission primarily originates from a population of approximately a dozen embedded super star clusters in the early stages of formation. We find that emission from these clusters is characterized by electron temperatures ranging from 7000 to 10,000 K and measures an average singly ionized helium abundance Y + = 0.25 0.06, both of which are consistent with values measured for H ii regions in the center of the Milky Way. We also report the discovery of unusually broad line width recombination line emission originating from seven of the embedded clusters. We suggest that these clusters contribute to the launching of the large-scale hot wind observed to emanate from the central starburst. Finally, we use the measured recombination line fluxes to improve the characterization of overall embedded cluster properties, including the distribution of cluster masses and the fractional contribution of the clustered star formation to the total starburst, which we estimate is at least 50%.

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Atomic Carbon in the Central Molecular Zone of the Milky Way : Possible Cosmic–ray Induced Chemistry or Time–dependent Chemistry Associated with SNR Sagittarius A East

Kunihiko Tanaka, Makoto Nagai, Kazuhisa Kamegai

Astrophysical Journal (IOP publishing )  915 ( 2 ) 79 2021.07

Research paper (scientific journal), Joint Work, Lead author, Accepted,  ISSN  0004637X

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Atomic carbon (C0), being one of the most abundant atomic/molecular species observed in dense molecular gas, is potentially a good tracer of molecular gas mass in many chemical/physical environments, though the variation in C0 abundance outside the Galactic disk region is not yet fully known. This paper presents a wide-field 500 GHz [C i] map of the Galactic central molecular zone (CMZ) obtained with the ASTE 10 m telescope. Principal component analysis and non-LTE multi-transition analysis have shown that [C i] emission predominantly originates from the low-excitation gas component with a temperature of 20-50 K and density of ∼103 cm-3, whereas C0 abundance is likely suppressed in the high-excitation gas component. The average N(C0)/N(CO) abundance ratio in the CMZ is 0.3-0.4, which is 2-3 times that in the Galactic disk. The N(C0)/N(CO) ratio increases to 0.7 in the innermost 10 pc region and to ∼2 in the circumnuclear disk. We discovered C0-rich regions distributed in a ring shape encircling the supernova remnant (SNR) Sgr A East, indicating that the C0 enrichment in the central 10 pc region is a consequence of a molecular cloud-SNR interaction. In the 15 atoms/molecules included in principal component analysis, CN is the only other species that increases in the [C i]-bright ring. The origin of the [C i]-bright ring is likely a cosmic-ray-dominated region created by low-energy cosmic-ray particles accelerated by Sgr A East or primitive molecular gas collected by the SNR in which the conversion from C0 to CO has not reached equilibrium.

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The Distribution and Origin of C$_2$H in NGC 253 from ALCHEMI

J. Holdship, S. Viti, S. Martín, N. Harada, J. Mangum, K. Sakamoto, S. Muller, K. Tanaka, Y. Yoshimura, K. Nakanishi, R. Herrero-Illana, S. Mühle, R. Aladro, L. Colzi, K. L. Emig, S. García-Burillo, C. Henkel, P. Humire, D. S. Meier, V. M. Rivilla, P. van der Werf

A&A 654, A55 (2021) (Astronomy and Astrophysics)  654 2021.07

Research paper (scientific journal), Joint Work,  ISSN  00046361

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Observations of chemical species can provide an insight into the physical
conditions of the emitting gas but it is important to understand how their
abundances and excitation vary within different heating environments. C$_2$H is
a molecule typically found in PDR regions of our own Galaxy but there is
evidence to suggest it also traces other regions undergoing energetic
processing in extragalactic environments. As part of the ALCHEMI ALMA large
program, the emission of C$_2$H in the central molecular zone of the nearby
starburst galaxy NGC 253 was mapped at 1.6 " (28 pc) resolution and
characterized to understand its chemical origins. Spectral modelling of the
N=1-0 through N=4-3 rotational transitions of C$_2$H was used to derive the
C$_2$H column densities towards the dense clouds in NGC 253. Chemical
modelling, including PDR, dense cloud, and shock models were then used to
investigate the chemical processes and physical conditions that are producing
the molecular emission. We find high C$_2$H column densities of $\sim 10^{15}
cm^{-3}$ detected towards the dense regions of NGC 253. We further find that
these column densities cannot be reproduced by assuming that the emission
arises from the PDR regions at the edge of the clouds. Instead, we find that
the C$_2$H abundance remains high even in the high visual extinction interior
of these clouds and that this is most likely caused by a high cosmic-ray
ionization rate.


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HCN J = 4–3, HNC J = 1–0, H 13 CN J = 1–0, and HC 3 N J = 10–9 Maps of the Galactic Center Region. II: Physical Properties of Dense Gas Clumps and Propbability of Star Formation

Kunihiko Tanaka, Makoto Nagai, Kazuhisa Kamegai, Takahiro Iino, Takeshi Sakai

Astrophysical Journal (IOP publishing)  903   111 2020.11

Research paper (scientific journal), Joint Work, Accepted

HCN J = 4–3, HNC J = 1–0, H 13 CN J = 1–0, and HC 3 N J = 10–9 Maps of the Galactic Center Region. I. Spatially Resolved Measurements of Physical Conditions and Chemical Composition

TANAKA Kunihiko Makoto Nagai Kazuhisa Kamegai Takahiro Iino Takeshi Sakai

The Astrophysical Journal Supplement Series (IOP)  236 ( 2 ) 40 2018.06

Research paper (scientific journal), Joint Work, Accepted

ALMA Images of the Host Cloud of the Intermediate-mass Black Hole Candidate CO-0.40-0.22$^*$: No Evidence for Cloud--Black Hole Interaction, but Evidence for a Cloud--Cloud Collision

TANAKA Kunihiko

Astrophysical Journal (IOP publishing)  859 ( 2 ) 86 - 100 2018.06

Research paper (scientific journal), Accepted,  ISSN  0004637X

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This paper reports a reanalysis of archival ALMA data of the high velocity(-width) compact cloud CO-0.40-0.22, which has recently been hypothesized to host an intermediate-mass black hole (IMBH). If beam-smearing effects, difference in beam sizes among frequency bands, and Doppler shift due to the motion of the Earth are considered accurately, none of the features reported as evidence for an IMBH in previous studies are confirmed in the reanalyzed ALMA images. Instead, through analysis of the position-velocity structure of the HCN J = 3-2 data cube, we have found kinematics typical of a cloud-cloud collision (CCC), namely, two distinct velocity components bridged by broad emission features with elevated temperatures and/or densities. One velocity component has a straight filamentary shape with approximately constant centroid velocities along its length but with a steep, V-shaped velocity gradient across its width. This contradicts the IMBH scenario but is consistent with a collision between two dissimilar-sized clouds. From a non-LTE analysis of the multitransition methanol lines, the volume density of the post-shock gas has been measured to be 106 cm-3, indicating that the CCC shock can compress gas in a short timescale to densities typical of star-forming regions. Evidence for star formation has not been found, possibly because the cloud is in an early phase of CCC-triggered star formation or because the collision is nonproductive.

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A statistical study of giant molecular clouds traced by 13CO, C18O, CS, and CH3OH in the disk of NGC 1068 based on ALMA observations

Tosaki, Tomoka; Kohno, Kotaro; Harada, Nanase; Tanaka, Kunihiko; Egusa, Fumi; Izumi, Takuma; Takano, Shuro; Nakajima, Taku; Taniguchi, Akio; Tamura, Yoichi

Publications of the Astronomical Society of Japan (Oxford University Press on behalf of the Astronomical Society of Japan)   2017.01

Research paper (scientific journal), Joint Work, Accepted

Search for the CO-dark Mass in the Central Molecular Zone by using the ASTE 10-m Telescope

TANAKA Kunihiko

The Multi-Messenger Astrophysics of the Galactic Centre, Proceedings of the International Astronomical Union, IAU Symposium    107 - 110 2017.01

Research paper (international conference proceedings), Single Work

Physical Contact between the +20 km s^{-1} Cloud and the Galactic Circumnuclear Disk

Takekawa, Shunya; Oka, Tomoharu; Tanaka, Kunihiko

The Astrophysical Journal, 834 ( 2 ) 121 2017.01

Accepted

CO-0.30-0.07: a Peculiar Molecular Clump with an Extremely Broad Velocity Width in the Central Molecular Zone of the Milky Way

TANAKA Kunihiko

The Astrophysical Journal (IOP publishing)  806   130 - 142 2015.06

Research paper (scientific journal), Joint Work, Accepted

CO-0.30-0.07: A Candidate Site of Collision-induced Massive Star Formation in the Milky Way's Central Molecular Zone

TANAKA Kunihiko

Conditions and Impact of Star Formation. Edited by R. Simon, R. Schaaf and J. Stutzki. EAS Publications Series 75-76   181 - 184 2015.05

Research paper (international conference proceedings), Single Work

Dense Molecular Clumps Associated with the Large Magellanic Cloud Supergiant Shells LMC 4 and LMC 5

Fujii, Kosuke; Minamidani, Tetsuhiro; Mizuno, Norikazu; Onishi, Toshikazu; Kawamura, Akiko; Muller, Erik; Dawson, Joanne; Tatematsu, Ken'ichi; Hasegawa, Tetsuo; Tosaki, Tomoka; Miura, Rie E.; Muraoka, Kazuyuki; Sakai, Takeshi; Tsukagoshi, Takashi; Tanaka, Kunihiko; Ezawa, Hajime; Fukui, Yasuo

The Astrophysical Journal 796 ( 2 ) 123 - 141 2014.12

Research paper (scientific journal), Joint Work, Accepted

Millimeter-wave Spectral Line Surveys toward the Galactic Circumnuclear Disk and Sgr A*

Takekawa, Shunya; Oka, Tomoharu; Tanaka, Kunihiko; Matsumura, Shinji; Miura, Kodai; Sakai, Daisuke

The Astrophysical Journal Supplement 214 ( 1 )  2014.09

Research paper (scientific journal), Joint Work, Accepted

Millimeter-wave Molecular Line Observations of the Tornado Nebula

Sakai, D.; Oka, T.; Tanaka, K.; Matsumura, S.; Miura, K.; Takekawa, S.

The Astrophysical Journal 791 ( 1 )  2014.08

Research paper (scientific journal), Joint Work, Accepted

High Velocity Compact Clouds in the Sagittarius C Region

TTanaka, Kunihiko; Oka, Tomoharu; Matsumura, Shinji; Nagai, Makoto; Kamegai, Kazuhisa

Astrophysical Journal 783   62-71 2014.03

Research paper (scientific journal), Joint Work, Accepted

The ASTE Galactic Center Survey in the 350 and 500 GHz Bands

Tanaka, K.; Oka, T.; Matsumura, S.; Kamegai, K.; Nagai, M.

New Trends in Radio Astronomy in the ALMA Era: The 30th Anniversary of Nobeyama Radio Observatory, Proceedings of a Symposium held in Hakone, Japan 3-8 December 2012. ASP Conference Series, Vol. 476. San Francisco (Astronomical Society of the Pacific)     77 2013.10

Research paper (international conference proceedings), Joint Work

Kinematics of Shocked Molecular Gas Adjacent to the Supernova Remnant W44

Sashida, T., Oka, T., Tanaka, K., Aono, K., Matsumura, S., Nagai, M., & Seta, M

Astrophysical Journal 774 ( 1 ) 7 2013.08

Research paper (scientific journal), Joint Work, Accepted

Discovery of the Pigtail Molecular Cloud in the Galactic Center

Matsumura, S., Oka, T., Tanaka, K., Nagai, M., Kamegai, K., & Hasegawa, T.

Astrophysical Journal 756 ( 1 ) 87 2012.09

Research paper (scientific journal), Joint Work, Accepted

ASTE CO J=3-2 Survey of the Galactic Center

Oka, T., Onodera, Y., Nagai, M., Tanaka, K., Matsumura, S., Kamegai, K.

Astrophysical Journal Supplement 201 ( 2 ) 140 2012.08

Research paper (scientific journal), Joint Work, Accepted

High C^0 Abundance of Galactic Center Molecular Clouds

Tanaka, Kunihiko; Oka, Tomoharu; Matsumura, Shinji; Nagai, Makoto; Kamegai, Kazuhisa

Astrophysical Journal Letters  ( 743 ) L39 2011.12

Research paper (scientific journal), Joint Work, Accepted

Temperature Variations of Cold Dust in the Triangulum Galaxy M 33

Komugi, S., Tosaki, T., Kohno, K., Tsukagoshi, T., Nakanishi, K., Sawada, T., Kawabe, R., Ezawa, H., Kuno, N., Onodera, S., Tamura, Y., Wilson, G. W., Yun, M.-S., Scott, K. S., Perera, T. A., Austermann, J. E., Hughes, D. H., Aretxaga, I., #H Tanaka, K.#H, Muraoka, K., Miura, R., & Egusa, F.

Publications of Astronomical Society Japan 63 ( 1 ) 1139 2011.10

Research paper (scientific journal), Joint Work, Accepted

Detection of an ultrabright submillimetre galaxy in the Subaru/XMM-Newton Deep Field using AzTEC/ASTE

Ikarashi, S.; Kohno, K.; Aguirre, J. E.; Aretxaga, I.; Arumugam, V.; Austermann, J. E.; Bock, J. J.; Bradford, C. M.; Cirasuolo, M.; Earle, L.; Ezawa, H.; Furusawa, H.; Furusawa, J.; Glenn, J.; Hatsukade, B.; Hughes, D. H.; Iono, D.; Ivison, R. J.; Johnson, S.; Kamenetzky, J.; Kawabe, R.; Lupu, R.; Maloney, P.; Matsuhara, H.; Mauskopf, P. D.; Motohara, K.; Murphy, E. J.; Nakajima, K.; Nakanishi, K.; Naylor, B. J.; Nguyen, H. T.; Perera, T. A.; Scott, K. S.; Shimasaku, K.; Takagi, T.; Takata, T.; Tamura, Y.; Tanaka, K.; Tsukagoshi, T.; Wilner, D. J.; Wilson, G. W.; Yun, M. S.; Zmuidzinas, J.

Monthly Notices of the Royal Astronomical Society 415 ( 4 ) 3081 - 3096 2011.08

Research paper (scientific journal), Joint Work, Accepted

Large Scale Distribution of CN in the Central Molecular Zone: PDR or Weak XDR?

Tanaka, K.; Oka, T.; Nagai, M.; Kamegai, K.

The Galactic Center: a Window to the Nuclear Environment of Disk Galaxies. Proceedings of a workshop held at Shanghai, China on October 19-23, 2009. Edited by Mark R. Morris, Q. Daniel Wang, and Feng Yuan. San Francisco (Astronomical Society of the Pacific)     33 2011.05

Research paper (international conference proceedings), Joint Work

A New Look at the Galactic Circumnuclear Disk

Oka, T., Nagai, M., Kamegai, K., & Tanaka, K.

Astrophysical Journal 732 ( 2 ) 120 - 129 2011.05

Research paper (scientific journal), Joint Work, Accepted

Dense Clumps in Giant Molecular Clouds in the Large Magellanic Cloud: Density and Temperature Derived from 13CO(J = 3-2) Observations

Minamidani, Tetsuhiro; Tanaka, Takanori; Mizuno, Yoji; Mizuno, Norikazu; Kawamura, Akiko; Onishi, Toshikazu; Hasegawa, Tetsuo; Tatematsu, Ken'ichi; Takekoshi, Tatsuya; Sorai, Kazuo; Moribe, Nayuta; Torii, Kazufumi; Sakai, Takeshi; Muraoka, Kazuyuki; Tanaka, Kunihiko; Ezawa, Hajime; Kohno, Kotaro; Kim, Sungeun; Rubio, Mónica; Fukui, Yasuo

Astronomical Journal 141 ( 3 ) 73 - 84 2011.03

Research paper (scientific journal), Joint Work, Accepted

AzTEC/ASTE 1.1-mm survey of the AKARI Deep Field South: source catalogue and number counts

Hatsukade, B.; Kohno, K.; Aretxaga, I.; Austermann, J. E.; Ezawa, H.; Hughes, D. H.; Ikarashi, S.; Iono, D.; Kawabe, R.; Khan, S.; Matsuo, H.; Matsuura, S.; Nakanishi, K.; Oshima, T.; Perera, T.; Scott, K. S.; Shirahata, M.; Takeuchi, T. T.; Tamura, Y.; Tanaka, K.; Tosaki, T.; Wilson, G. W.; Yun, M. S.

Publication: Monthly Notices of the Royal Astronomical Society 411 ( 1 ) 102 - 116 2011.02

Research paper (scientific journal), Joint Work, Accepted

High Excitation Molecular Gas in the Galactic Center Loops; 12CO (J = 2-1 and J = 3-2) Observation

Kudo, Natsuko; Torii, Kazufumi; Machida, Mami; Davis, Timothy A.; Tsutsumi, Kazuki; Fujishita, Motusuji; Moribe, Nayuta; Yamamoto, Hiroaki; Okuda, Takeshi; Kawamura, Akiko; Mizuno, Norikazu; Onishi, Toshikazu; Maezawa, Hiroyuki; Mizuno, Akira; Tanaka, Kunihiko; Yamaguchi, Nobuyuki; Ezawa, Hajime; Takahashi, Kunio; Nozawa, Satoshi; Matsumoto, Ryoji; Fukui, Yasuo

Publications of the Astronomical Society of Japa 63 ( 1 ) 171 - 197 2011.02

Research paper (scientific journal), Joint Work, Accepted

Temperature and Density in the Foot Points of the Molecular Loops in the Galactic Center; Analysis of Multi-J Transitions of 12CO (J = 1--0, 3--2, 4--3, 7--6), 13CO (J = 1--0), and C18O (J = 1--0)

Torii, Kazufumi; Kudo, Natsuko; Fujishita, Motosuji; Kawase, Tokuichi; Okuda, Takeshi; Yamamoto, Hiroaki; Kawamura, Akiko; Mizuno, Norikazu; Onishi, Toshikazu; Machida, Mami; Takahashi, Kunio; Nozawa, Satoshi; Matsumoto, Ryoji; Ott, Jürgen; Tanaka, Kunihiko; Yamaguchi, Nobuyuki; Ezawa, Hajime; Stutzki, Jürgen; Bertoldi, Frank; Koo, Bon-Chul; Bronfman, Leonardo; Burton, Michael; Benz, Arnold O.; Ogawa, Hideo; Fukui, Yasuo

Publications of the Astronomical Society of Japa 63 ( 3 ) 675 - 695 2010.06

Research paper (scientific journal), Joint Work, Accepted

ASTE CO (3-2) Mapping Toward the Whole Optical Disk of M 83: Properties of Inter-arm Giant Molecular-Cloud Associations

Muraoka, Kazuyuki; Kohno, Kotaro; Tosaki, Tomoka; Kuno, Nario; Nakanishi, Kouichiro; Sorai, Kazuo; Sawada, Tsuyoshi; Tanaka, Kunihiko; Handa, Toshihiro; Fukuhara, Masayuki; Ezawa, Hajime; Kawabe, Ryohei

Astrophysical Journal, Volume 706 ( 2 ) 1213 - 1225 2009.12

Research paper (scientific journal), Joint Work, Accepted

A Large Molecular Arc in the Sagittarius B1 Complex

Tanaka, Kunihiko; Oka, Tomoharu; Nagai, Makoto; Kamegai, Kazuhisa

Publications of Astronomical Society of Japan 61 ( 3 ) 461 2009.06

Research paper (scientific journal), Joint Work, Accepted

Spatial correlation between submillimetre and Lyman-α galaxies in the SSA22 protocluster

Tamura, Yoichi; Kohno, Kotaro; Nakanishi, Kouichiro; Hatsukade, Bunyo; Iono, Daisuke; Wilson, Grant W.; Yun, Min S.; Takata, Tadafumi; Matsuda, Yuichi; Tosaki, Tomoka; Ezawa, Hajime; Perera, Thushara A.; Scott, Kimberly S.; Austermann, Jason E.; Hughes, David H.; Aretxaga, Itziar; Chung, Aeree; Oshima, Tai; Yamaguchi, Nobuyuki; Tanaka, Kunihiko; Kawabe, Ryohei

Nature 759 ( 7243 ) 61 - 63 2009.05

Research paper (scientific journal), Joint Work, Accepted

ASTE CO(3-2) Observations of the Southern Barred Spiral Galaxy NGC 986: a Large Gaseous Bar Filled with a Dense Molecular Medium

Kohno, Kotaro; Tosaki, Tomoka; Miura, Rie; Muraoka, Kazuyuki; Sawada, Tsuyoshi; Nakanishi, Kouichiro; Kuno, Nario; Sakai, Takeshi; Sorai, Kazuo; Kamegai, Kazuhisa; Tanaka, Kunihiko; Okuda, Takeshi; Endo, Akira; Hatsukade, Bunyo; Sameshima, Masahiro; Ezawa, Hajime; Sakamoto, Seiichi; Kamazaki, Takeshi; Yamaguchi, Nobuyuki; Cortés, Juan; Tamura, Yoichi; Fukuhara, Masayuki; Iono, Daisuke; Kawabe, Ryohei;

Publications of the Astronomical Society of Japan 60 ( 3 ) 457 - 464 2008.06

Research paper (scientific journal), Joint Work, Accepted

High-Resolution Mappings of the l=1°.3 Complex in Molecular Lines: Discovery of a Proto-Superbubble

Tanaka, Kunihiko; Kamegai, Kazuhisa; Nagai, Makoto; Oka, Tomoharu

Publications of Astronomical Society of Japan 59 ( 2 ) 323 2007.04

Research paper (scientific journal), Single Work

A CO J = 3-2 Survey of the Galactic Center

Oka, Tomoharu; Nagai, Makoto; Kamegai, Kazuhisa; Tanaka, Kunihiko; Kuboi, Nobuyuki

Publications of the Astronomical Society of Japan 59 ( 1 ) 15 - 23 2007.02

Research paper (scientific journal), Joint Work, Accepted

ASTE CO (3-2) Observations of the Barred Spiral Galaxy M 83: I. Correlation between CO (3-2)/ CO (1-0) Ratios and Star Formation Efficiencies

Muraoka, Kazuyuki; Kohno, Kotaro; Tosaki, Tomoka; Kuno, Nario; Nakanishi, Kouichiro; Sorai, Kazuo; Okuda, Takeshi; Sakamoto, Seiichi; Endo, Akira; Hatsukade, Bunyo; Kamegai, Kazuhisa; Tanaka, Kunihiko; Cortes, Juan; Ezawa, Hajime; Yamaguchi, Nobuyuki; Sakai, Takeshi; Kawabe, Ryohei

Publications of the Astronomical Society of Japan 59 ( 1 ) 43 - 54 2007.02

Research paper (scientific journal), Joint Work, Accepted

Physical Conditions of Molecular Gas in the Galactic Center

Nagai, Makoto; Tanaka, Kunihiko; Kamegai, Kazuhisa; Oka, Tomoharu

Publications of the Astronomical Society of Japan 59 ( 1 ) 25 - 31 2007.02

Research paper (scientific journal), Joint Work, Accepted

Atomic Carbon in the Southern Milky Way

Oka, Tomoharu; Kamegai, Kazuhisa; Hayashida, Masaaki; Nagai, Makoto; Ikeda, Masafumi; Kuboi, Nobuyuki; Tanaka, Kunihiko; Bronfman, Leonardo; Yamamoto, Satoshi

Astrophysical Journal 623 ( 2 ) 889 - 896 2005.04

Research paper (scientific journal), Joint Work, Accepted

A 350GHz SIS Receiver on the Nobeyama 10m Submillimeter Telescope

Sekimoto, Yutaro; Sakai, Takeshi; Saito, Gaku; Tatematsu, Ken'ichi; Tanaka, Kunihiko; Kohno, Kotaro; Noguchi, Takashi; Iwashita, Hiroyuki; Takahashi, Toshikazu; Satou, Naohisa; Yokogawa, Sozo; Sakamoto, Seiichi; Ukita, Nobuharu; Kawabe, Ryohei; Ito, Tetsuya; Maezawa, Hiroyuki; Yamamoto, Satoshi

Publications of the Astronomical Society of Japan 53 ( 5 ) 951 - 958 2001.10

Research paper (scientific journal), Joint Work, Accepted