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People > Research Fellow > Curriculum Vita
The circumstellar disk of AB Aurigae: evidence for envelope accretion at late stages of star formation?
Carbon-chain and Organic Molecules around Very Low Luminosity Protostellar Objects of L1521F-IRS and IRAM 04191+1522
Rotating Gas Motion around Protostars
Two SMA antennas built in Taiwan
The Submillimeter Array
The Submillimeter Array
Signing Ceremony between NINS and AS
Images of circumstellar disks around Herbig Ae stars, obtained in 345 GHz dust emission (contours) using the SMA
Dewar of the ALMA receiver
Conceptual image of ALMA
Ohashi, Nagayoshi
Research Fellow (Temporary Transfer: Associate Director, Subaru Telescope of NAOJ in Hawaii)
photo of Ohashi, Nagayoshi
Office: Subaru Telescope of NAOJ in Hawaii
Email: ohashi_replace2@_asiaa.sinica.edu.tw

Education and Positions

  • Associate Director and Professor, Subaru Telescope (2011~present)
  • Research Fellow, ASIAA (2007~present)
  • Assistant Director, ASIAA (2008~2011)
  • ALMA-Taiwan Project Manager (2005~2011)
  • SMART/SMA-Taiwan Project Scientist (2000~2011)
  • Associate Research Fellow, ASIAA (2000~2007)
  • Assistant Research Fellow, ASIAA (1997~2000)
  • Submillimeter Array Postdoctoral Fellow, Harvard-Smithsonian Center for Astrophysics (1994~1997)
  • JSPS Fellowship, Nobeyama Radio Observatory (1992~1994)
  • Ph.D., Physics, Nagoya University (1992)
  • M.S., Physics, Nagoya University (1989)

Honors & Awards

  • NSC (Taiwan) Research Award (1999~2000)
  • The Astronomical Society of Japan (ASJ) Young Astronomer Award (1999)

Research Interests

How stars like the Sun and planets like the Earth are formed? In order to answer this question, I have been using radio telescopes, particularly radio interferometers, to observe nearby star and planet forming regions. Radio interferometers allow us to observe fine structures of dense cores and disks where stars and planets form. In order to have better observational tools, I also have been working to build radio telescopes (Submillimeter Array and Atacama Millimeter and Submillimeter Array). My near future goal is to image protoplanetary disks at a resolution of 0.01”.

Recent Journal Papers

  1. Yen Hsi-Wei, Zhao Bo, Koch Patrick M., Krasnopolsky Ruben, Li Zhi-Yun, Ohashi Nagayoshi, Takakuwa Shigehisa, "Constraint on ion–neutral drift velocity in the Class 0 protostar B335 from ALMA observations" , Astronomy & Astrophysics: 615, A58, 2018-07 [SCI] (Fulltext)
  2. Soam A; Pattle K; Ward-Thompson D; ...; Koch PM; ...; Lai SP; ...; Rao R; ...; Chen R-H; ....; Kemper F; ...; Liu SY; ...; Ohashi N; ...; Tang YW; ...; Yen HW; et al., "Magnetic Fields toward Ophiuchus-B Derived from SCUBA-2 Polarization Measurements" , The Astrophysical Journal: 861(1), 65, 2018-07 [SCI] (Fulltext)
  3. Maury A J, Girart J M, Zhang Q, Hennebelle P, Keto E, Rao R, Lai S-P, Ohashi N, Galametz M, "Magnetically regulated collapse in the B335 protostar? I. ALMA observations of the polarized dust emission" , Monthly Notices of the Royal Astronomical Society: 477(2), 2760-2765, 2018-06 [SCI] (Fulltext)
  4. Aso Yusuke, Ohashi Nagayoshi, Aikawa Yuri, Machida Masahiro N., Saigo Kazuya, Saito Masao, Takakuwa Shigehisa, Tomida Kengo, Tomisaka Kohji, Yen Hsi-Wei, Williams Jonathan P., "ALMA Observations of SMM11 Reveal an Extremely Young Protostar in Serpens Main Cluster" , The Astrophysical Journal: 850(1), L2, 2017-11 [SCI] (Fulltext)
  5. Aso Yusuke, Ohashi Nagayoshi, Aikawa Yuri, Machida Masahiro N., Saigo Kazuya, Saito Masao, Takakuwa Shigehisa, Tomida Kengo, Tomisaka Kohji, Yen Hsi-Wei, "ALMA Observations of the Protostar L1527 IRS: Probing Details of the Disk and the Envelope Structures" , The Astrophysical Journal: 849(1), 56, 2017-11 [SCI] (Fulltext)
  6. Tang Y-W*; Guilloteau S; Dutrey A; ...; Gu PG; ...; Ho PTP; ...; Ohashi N; et al., "Planet Formation in AB Aurigae: Imaging of the Inner Gaseous Spirals Observed inside the Dust Cavity" , ASTROPHYSICAL JOURNAL: 840(1), 32, 2017-05 [SCI] (Fulltext)
  7. Yen Hsi-Wei, Koch Patrick M., Takakuwa Shigehisa, Krasnopolsky Ruben, Ohashi Nagayoshi, Aso Yusuke, "SIGNS OF EARLY-STAGE DISK GROWTH REVEALED WITH ALMA" , The Astrophysical Journal: 834(2), 178, 2017-01 [SCI] (Fulltext)
  8. Aso Yusuke, Ohashi Nagayoshi, Saigo Kazuya, Koyamatsu Shin, Aikawa Yuri, Hayashi Masahiko, Machida Masahiro N., Saito Masao, Takakuwa Shigehisa, Tomida Kengo, Tomisaka Kohji, Yen Hsi-Wei, "ALMA OBSERVATIONS OF THE TRANSITION FROM INFALL MOTION TO KEPLERIAN ROTATION AROUND THE LATE-PHASE PROTOSTAR TMC-1A" , The Astrophysical Journal: 812(1), 27, 2015-10 [SCI] (Fulltext)
  9. Yen Hsi-Wei, Takakuwa Shigehisa, Koch Patrick M., Aso Yusuke, Koyamatsu Shin, Krasnopolsky Ruben, Ohashi Nagayoshi, "NO KEPLERIAN DISK >10 AU AROUND THE PROTOSTAR B335: MAGNETIC BRAKING OR YOUNG AGE?" , The Astrophysical Journal: 812(2), 129, 2015-10 [SCI] (Fulltext)
  10. ALMA Partnership; Fomalont EB; Vlahakis C; ...; Matsushita S; …; Espada D.; …; Chapillon E; ...; Hasegawa T; ...; Ohashi N; ...; Huang Y-D; Liu S-Y; Kemper F; Koch PM; Chen M-T; ...; Su Y-N; Trejo-Cruz A; Wang K-S; ...; Ho PTP; et al., "THE 2014 ALMA LONG BASELINE CAMPAIGN: AN OVERVIEW" , The Astrophysical Journal: 808(1), L1, 2015-07 [SCI] (Fulltext)
  11. Yen H-W; Koch PM; Takakuwa S; Ho PTP; Ohashi N; Tang Y-W, "Observations of Infalling and Rotational Motions on a 1,000-AU Scale around 17 Class 0 and 0/I Protostars: Hints of Disk Growth and Magnetic Braking?" , ASTROPHYSICAL JOURNAL: 799(2), 193, 2015-02 [SCI] (Fulltext)
  12. Hashimoto J; Tsukagoshi T; Brown JM; Dong R; ...; Ohashi N; ...; Takami M; et al., "THE STRUCTURE OF PRE-TRANSITIONAL PROTOPLANETARY DISKS. II. AZIMUTHAL ASYMMETRIES, DIFFERENT RADIAL DISTRIBUTIONS OF LARGE AND SMALL DUST GRAINS IN PDS 70," , The Astrophysical Journal: 799(1), 43, 2015-01 [SCI] (Fulltext)
  13. Nagayoshi Ohashi, Kazuya Saigo, Yusuke Aso, Yuri Aikawa, Shin Koyamatsu, Masahiro N. Machida, Masao Saito, Sanemichi Z. Takahashi, Shigehisa Takakuwa, Kengo Tomida, Kohji Tomisaka, & Hsi-Wei Yen, "Formation of a Keplerian Disk in the Infalling Envelope around L1527 IRS: Transformation from Infalling Motions to Kepler Motions" , ASTROPHYSICAL JOURNAL: 796, 131 (11pp), 2014-12 [SCI]
  14. Chou T-L; Takakuwa S; Yen H-W; Ohashi N; Ho PTP, "Transition from the Infalling Envelope to the Keplerian Disk around L1551 IRS 5" , ASTROPHYSICAL JOURNAL: 796, 70 (15pp), 2014-11 [SCI] (Fulltext)
  15. Yen H-W; Takakuwa S; Ohashi N; et al, "ALMA Observations of Infalling Flows Toward the Keplerian Disk Around the Class I Protostar L1489 IRS" , ASTROPHYSICAL JOURNAL: 793(1), 1, 2014-09 [SCI] (Fulltext)
  16. Nami Sakai, Yoko Oya, Takeshi Sakai, Yoshimasa Watanabe, Tomoya Hirota, Cecilia Ceccarelli, Claudine Kahane, Ana Lopez-Sepulcre, Bertrand Lefloch, Charlotte Vastel, Sandrine Bottinelli, Emmanuel Caux, Audrey Coutens, Yuri Aikawa, Shigehisa Takakuwa, Nagayoshi Ohashi, Hsi-Wei Yen, & Satoshi Yamamoto, "A Chemical View of Protostellar-Disk Formation in L1527" , Astrophysical Journal Letters: 791, L38 (5pp), 2014-08 [SCI]
  17. Shin Koyamatsu, Shigehisa Takakuwa, Masahiko Hayashi, Satoshi Mayama, & Nagayoshi Ohashi, "The Disappearing Envelope around the Transitional Class I Object L43" , ASTROPHYSICAL JOURNAL: 789, 95 (13pp), 2014-07 [SCI]
  18. Sakai N; Sakai T; Hirota T; ...; Ohashi N; Takakuwa S; Yen H-W; et al., "Change in the chemical composition of infalling gas forming a disk around a protostar" , NATURE: 507(7490), 78-80, 2014-03 [SCI] (Fulltext)
  19. Takahashi S; Ohashi N; Bourke LT, "Direct Imaging of a Compact Molecular Outflow from a Very Low-luminosity Object" , ASTROPHYSICAL JOURNAL: 774(1), 20, 2013-09 [SCI] (Fulltext)
  20. Yen H-W; Takakuwa S; Ohashi N; Ho PTP, "Unveiling the Evolutionary Sequence from Infalling Envelopes to Keplerian Disks around Low-Mass Protostars" , ASTROPHYSICAL JOURNAL: 772(1), 22, 2013-07 [SCI] (Fulltext)
  21. Tang Y-W; Guilloteau S; Pietu V; Dutrey A; Ohashi N; Ho PTP, "The circumstellar disk of AB Aurigae: evidence for envelope accretion at late stages of star formation?" , ASTRONOMY & ASTROPHYSICS: 547, A84, 2012-11 [SCI] (Fulltext)
  22. Muto T; ...; Ohashi N;...; Takami M; et al., "Discovery of Small-Scale Spiral Structures in the Disk of SAO 206462 (HD 135344B): Implications for the Physical State of the Disk from Spiral Density Wave Theory" , Astrophysical Journal Letters: 748(2), L22-28, 2012-03 [SCI] (Fulltext)
  23. Liu C-F; Shang H; Pyo T-S; Takami M; Walter FM; Yan C-H; Wang S-Y; Ohashi N; Hayashi M, "Is FS Tau B Driving an Asymmetric Jet?" , ASTROPHYSICAL JOURNAL: 749(1), 62-67, 2012-03 [SCI] (Fulltext)
  24. Maury A; Ohashi N; Andre P, "Subarcsecond SMA observations of the prototype Class 0 object VLA1623 at 1.3 mm: a single protostar with a structured outflow cavity?" , ASTRONOMY & ASTROPHYSICS: 539, A130, 2012-03 [SCI]
  25. Yen H-W; Takakuwa S; Ohashi N, "Kinematics and Physical Conditions of the Innermost Envelope in B335" , ASTROPHYSICAL JOURNAL: 742(1), 57, 2011-11 [SCI] (Fulltext)
  26. Lyo, A.; Ohashi, N.; Qi, C.; Wilner, D.; and Su, Y.-N., "Millimeter Observations of the Transition Disk around HD 135344B (SAO 206462)" , ASTRONOMICAL JOURNAL: 142(5), 151, 2011-11 [SCI] (Fulltext)
  27. Hashimoto J; ...; Ohashi N;...; Takami M; et al., "Direct Imaging of Fine Structures in Giant Planet Forming Regions of a Protoplanetary Disk" , ASTROPHYSICAL JOURNAL: 729(2), L17-20, 2011-03 [SCI] (Fulltext)
  28. Takakuwa S; Ohashi N; Aikawa Y, "Carbon-chain and Organic Molecules Around Very Low Luminosity Protostellar Objects of L1521F-IRS and IRAM 04191+1522" , ASTROPHYSICAL JOURNAL: 728(2), 101, 2011-02 [SCI]
  29. Karr JL; Ohashi N; Kudo T; Tamura M , "Candidate Coronagraphic Detections of Protoplanetary Disks around Four Young Stars " , Astronomical Journal: 139(3), 1015-1027, 2010-03 [SCI] (Fulltext)
  30. Momose M; Ohashi N; et al. , "High Resolution Observations of Dust Continuum Emission at 340 GHz from the Low-mass T Tauri Star FN Tauri" , Astrophysical Journal: 712(1), 397-404, 2010-03 [SCI] (Fulltext)
  31. Yen H-W; Takakuwa S; Ohashi N, "High-Velocity Jets and Slowly Rotating Envelope in B335" , ASTROPHYSICAL JOURNAL: 710(2), 1786-1799, 2010-02 [SCI] (Fulltext)
  32. Dai Y; Wilner DJ; Andrews SM; Ohashi N, "Millimeter Dust Emission in the GQ Lup System" , Astronomical Journal: 139(2), 626-629, 2010-02 [SCI] (Fulltext)
  33. Okamoto YK; ...; Ohashi N; et al., "Direct Detection of a Flared Disk Around a Young Massive Star HD200775 and its 10 to 1000 AU Scale Properties" , ASTROPHYSICAL JOURNAL: 706(1), 665-675, 2009-11 [SCI] (Fulltext)
  34. Karr JL; Manoj P; Ohashi N, "Gum 48d: an evolved HII region with ongoing star formation" , ASTROPHYSICAL JOURNAL: 697(1), 133-147, 2009-05 [SCI] (Fulltext)
  35. Phan-Bao N; ...; Lee CF; Tang YW; Ho PTP; ...; Lim J; Ohashi N; Shang H, "First Confirmed Detection of a Bipolar Molecular Outflow from a Young Brown Dwarf" , ASTROPHYSICAL JOURNAL: 689(2), L141-L144, 2008-12 [SCI] (Fulltext)
  36. Takahashi S; Saito M; Ohashi N; ...; Takakuwa S; et al., "Millimeter- and Submillimeter- Wave Observations of the OMC-2/3 Region. III. An Extensive Survey for Molecular Outflows" , ASTROPHYSICAL JOURNAL: 688(1), 344-361, 2008-11 [SCI] (Fulltext)
  37. Yeh SCC; Hirano N; ...; Ho PTP; Lee CF; Ohashi N; Takakuwa S, "The CO Molecular Outflows of IRAS 16293-2422 Probed by the Submillimeter Array" , ASTROPHYSICAL JOURNAL: 675(1), 454-463, 2008-03 [SCI] (Fulltext)
  38. Ohashi N, "Observational signature of planet formation: The ALMA view" , ASTROPHYSICS AND SPACE SCIENCE: 313(1-3), 101-107, 2008-01 [SCI] (Fulltext)
  39. Manoj P; Ho PTP; Ohashi N; Zhang Q; Hasegawa T; Chen HR; Bhatt HC; Ashok NM, "An evolved disk surrounding the massive main sequence star MWC 297?" , ASTROPHYSICAL JOURNAL: 667(2), L187-L190, 2007-10 [SCI] (Fulltext)
  40. Takakuwa S; Ohashi N; Bourke TL; Hirano N; Ho PTP; Jorgensen JK; Kuan YJ; et al., "Arcsecond-Resolution Submillimeter HCN Imaging of the Binary Protostar IRAS 16293-2422" , ASTROPHYSICAL JOURNAL: 662(1), 431-442, 2007-06 [SCI] (Fulltext)
  41. Jorgensen JK; Bourke TL; Myers PC; Di Francesco J; van Dishoeck EF; Lee CF; Ohashi N; Schoier FL; Takakuwa S; Wilner DJ; Zhang Q, "PROSAC: A Submillimeter Array Survey of Low-Mass Protostars I. Overview of Program: Envelopes, Disks, Outflows, and hot Cores" , ASTROPHYSICAL JOURNAL: 659(1), 479-498, 2007-04 [SCI] (Fulltext)
  42. Chen HR; Su YN; Liu SY; Hunter TR; Wilner DJ; Zhang Q; Lim J; Ho PTP; Ohashi N; Hirano N, "654 GHz Continuum and C18O(6-5) Observations of G240.31+0.07 with the Submillimeter Array" , ASTROPHYSICAL JOURNAL: 654(1), L87-L90, 2007-01 [SCI] (Fulltext)
  43. Lin SY; Ohashi N; Lim J; Ho PTP; Fukagawa M; Tamura M, "Possible Molecular Spiral Arms in the Protoplanetary Disk of AB Aur" , ASTROPHYSICAL JOURNAL: 645(2), 1297-1304, 2006-07 [SCI] (Fulltext)
  44. Qi C; Ho PTP; ...; Hirano N; Ohashi N; ...; Choi M; et al, "Imaging the Disk around TW Hydrae with the Submillimeter Array" , ASTROPHYSICAL JOURNAL: 616(1), L11-L14, 2004-11 [SCI] (Fulltext)
  45. Kuan YJ; ...; Hirano N; ...; Liu SY; Ohashi N; et al, "Organic Molecules in Low-Mass Protostellar Hot Cores: Submillimeter Imaging of IRAS 16293-2422" , ASTROPHYSICAL JOURNAL: 616(1), L27-L30, 2004-11 [SCI] (Fulltext)
  46. Su Y-N; Liu SY; Lim J; Ohashi N; ...; Ho PTP, "Search for Calibrators for the Submillimeter Array.I. High-Mass Star-forming Regions" , ASTROPHYSICAL JOURNAL: 616(1), L39-L42, 2004-11 [SCI] (Fulltext)
  47. Matsushita S; Sakamoto K; Kuo CY; Hsieh PY; Dinh-V-Trung; ...; Liu SY; Ohashi N; Lim J, "Submillimeter Array 12CO (J=3-2) Interferometric Observations of the Central Region of M51" , ASTROPHYSICAL JOURNAL: 616(1), L55-L58, 2004-11 [SCI] (Fulltext)
  48. Beuther H; Zhang Q; ...; Ho PTP; Liu SY; Ohashi N; Su YN; Lim J, "Submillimeter Array Multiline Observations of the Massive Star-forming Region IRAS 18089-1732" , ASTROPHYSICAL JOURNAL: 616(1), L19-L22, 2004-11 [SCI] (Fulltext)
  49. Young KH; ...; Hirano N; Ho PTP; Liu SY; Lo KY; Martin R; Matsushita S; ...; Ohashi N; ...; Patt F; …; Dihn-V-Trung, "Submillimeter Array Observations of CS J = 14-13 Emission from the Evolved Star IRC +10216" , ASTROPHYSICAL JOURNAL: 616(1), L51-L54, 2004-11 [SCI] (Fulltext)
  50. Takakuwa S; Ohashi N; ...; Hirano N; Choi M; et al, "Submillimeter Array Observations of L1551 IRS 5 in CS J = 7-6" , ASTROPHYSICAL JOURNAL: 616(1), L15-L18, 2004-11 [SCI] (Fulltext)
  51. Beuther H; Hunter TR; ...; Ho PTP; Ohashi N; Su YN; Lim J; Liu SY, "Submillimeter Array Outflow/Disk Studies in the Massive Star-forming Region IRAS 18089-1732" , ASTROPHYSICAL JOURNAL: 616(1), L23-L26, 2004-11 [SCI] (Fulltext)
  52. Sollins PK; Hunter TR; ...; Ho PTP; Lim J; Liu SY; Ohashi N; Sridharan TK; Su YN; et al, "Mapping the Outflow from G589-039 in SiO J = 5 --> 4" , ASTROPHYSICAL JOURNAL: 616(1), L35-L38, 2004-05 [SCI] (Fulltext)
  53. Shinnaga H; Ohashi N; Lee S-W; Moriarty-Schieven GH, "Physical Properties and Kinetic Structure of a Starless Core in Taurus Molecular Cloud" , ASTROPHYSICAL JOURNAL: 601(2), 962-978, 2004-02 [SCI] (Fulltext)
  54. Aikawa Y; Ohashi N; Herbst E, "Molecular Evolution in Collapsing Prestellar Cores. II. The Effect of Grain-Surface Reactions" , ASTROPHYSICAL JOURNAL: 593(2), 906-924, 2003-08 [SCI] (Fulltext)
  55. Takakuwa S; Ohashi N; Hirano N, "Interaction between the Outflow and the Core in IRAM 04191+1522" , ASTROPHYSICAL JOURNAL: Journal 590(2), 932-943, 2003-06 [SCI] (Fulltext)
  56. Di Francesco J; Myers PC; ... ; Ohashi N; et al., "Infall, outflow, rotation, and turbulent motions of dense gas within NGC 1333 IRAS 4" , ASTRONOMICAL JOURNAL: 562(2), 770-789, 2001-12 [SCI] (Fulltext)
  57. Aikawa Y; Ohashi N; ...; Takakuwa S, "Molecular evolution in collapsing prestellar cores" , ASTROPHYSICAL JOURNAL: 552(2), 639-653, 2001-05 [SCI] (Fulltext)
  58. Park YS; Panis JF; Ohashi N; Choi M; Minh YC, "Interferometric observation of the L483 molecular core" , ASTROPHYSICAL JOURNAL: 542(1), 344-351, 2000-10 [SCI] (Fulltext)
  59. Ohashi N; Lee SW; Wilner DJ; Hayashi M, "CCS imaging of the starless core L1544: An envelope with infall and rotation" , ASTROPHYSICAL JOURNAL: 518(1), L41-L44, 1999-06 [SCI] (Fulltext)
  60. Momose M; Ohashi N; Kawabe R; et al, "Aperture Synthesis C 18O J= 1-0 Observations of L1551 IRS 5: Detailed Structure of the Infalling Envelope" , ASTROPHYSICAL JOURNAL: 504(1), 314-333, 1998-09 [SCI] (Fulltext)
  61. Zhang QZ; Ho PTP; Ohashi N, "Dynamical Collapse in W51 Massive Cores: CS (3--2) and CH 3CN Observations" , ASTROPHYSICAL JOURNAL: 494(2), 636-656, 1998-02 [SCI] (Fulltext)
  62. Ohashi N; Hayashi M; Ho PTP; et al, "Rotation in the protostellar envelopes around IRAS 04169+2702 and IRAS 04365+2535: The size scale for dynamical collapse" , ASTROPHYSICAL JOURNAL: 488(1), 317-320, 1997-10 [SCI] (Fulltext)
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