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Associate Professor    Nagai, Hiroshi

Research Field

  • Radio Astronomy, High Energy Astrophysics


  • Ph. D.

Summary of Research

  • Relativistic jets emanating from the super massive black hole at the center of galaxies are the subject of extensive studies at multi messengers. Radio observations enable us to probe the jets in close vicinity of the black hole using VLBI technique with very high angular resolution and highlight the accretion flow feeding the black hole using millimeter and submillimeter interferometry such as ALMA. With these instruments, I am challenging to uncover the jet production mechanism in connection with the multi-wavelength emission and properties of accretion flow from galactic scale to black hole scale.

Research Achievements or Papers

  • Nagai et al. 2019, ApJ, 883, 193 “The ALMA Discovery of the Rotating Disk and Fast Outflow of Cold Molecular Gas in NGC 1275”
  • EHT Collaboration et al. 2019, ApJ, 875, L1-L6 “First M87 Event Horizon Telescope Results. I-VI”
  • Nagai et al. 2016, ApJ, 831, 12 “ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 286”
  • Nagai et al. 2014, ApJ, 785, 53 “Limb-brightened Jet of 3C 84 Revealed by the 43 GHz Very-Long-Baseline-Array Observation”
  • Nagai et al. 2010, PASJ, 62, L11 “VLBI Monitoring of 3C 84 (NGC 1275) in Early Phase of the 2005 Outburst”

Academic Society

  • Astronomical Society of Japan, International Astronomical Union

Academic Award

  • Breakthrough Prize in Fundamental Physics 2020
  • NAOJ Director Prize 2018

Web Page


  • hiroshi.nagai[at]
    (In the mailing address, replace [at] with @)