Associate Professor Makoto Kishimoto

Area and Subject Taught Observational Astrophysics
Research Theme(s) Supermassive black hole systems through super high spatial resolution observations
Academic Degrees Doctor of Science (Kyoto University)
Keywords for Research Field astrophysics, extragalactic astronomy, active galactic nuclei, supermassive black holes, optical/infrared interferometry
Office Phone Number Not Public
e-mail Not Public

Research Overview

Have you ever looked at the “center” of our Milky Way? The earth, where we live, belongs to the planetary system around the sun, and millions of millions of sun-like stars make up this Milky Way. It has a disk-like structure with a big, round structure called a bulge at the center. We can actually observe this huge structure with our own eyes, if we go to a suitable place like a desert in Chile or summit in Hawaii island. Probably quite surprisingly, we almost know that there is a supermassive black hole at this center of our Milky Way, with the hole’s mass being about 4 million times the Sun’s mass. Even further, there seems to be such a supermassive black hole at the center of each galaxy, i.e. not only in the Milky Way, with its mass being proportional to the mass of the bulge of each galaxy, according to recent studies.
A black hole can’t be supermassive unless a lot of mass actually falls onto it. This phenomenon, called “mass accretion”, also often accompanies “mass ejection” seen as a jet-like structure. The mass proportionality between the supermassive black hole and its host galaxy quite likely tells us that the accretion and ejection process around the black hole is intimately related to the formation and evolution process of the whole host galaxy itself. On the other hand, astronomers believe that the formation and evolution of galaxies involve collisions and mergers of galaxies: this would mean that there will be a binary black hole system at the center of the galaxy after the collision and merger… at least naively.
However, after many years of many people’s work, we still do not understand well the mass accretion and ejection processes, nor the existence of such binary black hole systems. Why? My view is that this is due to the absolute lack of suitable spatial resolution. The focus of my current research is to achieve super high spatial resolutions using interferometry in the optical and infrared wavelengths, and to ultimately look at supermassive black hole systems directly.

Notable Publications and Works in the Last Three Years

  • Hoenig & Kishimoto, “Dusty Winds in Active Galactic Nuclei: Reconciling Observations with Models”, The Astrophysical Journal Letters, 838, L20 (2017)
  • Hoenig, Watson, Kishimoto, et al., “Cosmology with AGN dust time lags-simulating the new VEILS survey”, Monthly Notices of Royal Astronomical Society, 464, 1693 (2017)
  • Gandhi, Hoenig, Kishimoto, “The dust sublimation radius as an outer envelope to the bulk of the narrow Fe Kalpha line emission in Type 1 AGN”, The Astrophysical Journal, 812, 113 (2015)
  • Hoenig, Watson, Kishimoto, Hjorth, “A dust-parallax distance of 19 megaparsecs to the supermassive black hole in NGC4151”, Nature, 515, 528 (2014)
  • Kishimoto, Hoenig, Antonucci, et al., “Evidence for a receding sublimation region around a supermassive black hole”, The Astrophysical Journal Letters, 775, L36 (2013)
  • Hoenig, Kishimoto, Tristram, et al., “Dust in the polar region as a major contributor to the infrared emission of active galactic nuclei”, The Astrophysical Journal, 771, 87 (2013)
  • Sluse, Kishimoto, Anguita, et al., “Mid-infrared microlensing of accretion disc and dusty torus in quasars: effects on flux ratio anomalies”,Astronomy & Astrophysics, 553, A53 (2013)
  • Kishimoto, Hoenig, Antonucci, et al.,“Probing the innermost dusty structure in AGN with mid-IR and near-IR interferometers”, Journal of Physics: Conference Series by Institute of Physics Publishing, 372, 2033 (2012)
  • Hoenig, Kishimoto, Antonucci, et al., “Parsec-scale dust emission from the polar region in the type 2 nucleus of NGC 424”, The Astrophysical Journal, 755, 149 (2012)
  • Weigelt, Hofmann, Kishimoto, et al., “VLTI/AMBER observations of the Seyfert nucleus of NGC3783”, Astronomy & Astrophysics Letter, 541, L9 (2012)
  • Kishimoto, Hoenig, Antonucci, et al., “Mapping the radial structure of AGN tori”, Astronomy & Astrophysics, 536, A78 (2011)
  • Kishimoto, Hoenig, Antonucci, et al., “The innermost dusty structure in active galactic nuclei as probed by the Keck interferometer”, Astronomy & Astrophysics, 527, A121 (2011)
  • Hoenig & Kishimoto, “Constraining properties of dusty environments by infrared variability”, Astronomy & Astrophysics, 534, A121 (2011)