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LUMINOSITY DEPENDENCE OF THE COVERING FACTOR OF THE DUST TORUS IN ACTIVE GALACTIC NUCLEI REVEALED BY AKARI

  • Toba, Yoshiki (Research Center for Space and Cosmic Evolution, Ehime University) ;
  • Oyabu, Shinki (Graduate School of Science, Nagoya University) ;
  • Matsuhara, Hideo (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency) ;
  • Ishihara, Daisuke (Graduate School of Science, Nagoya University) ;
  • Malkan, Matt A. (Department of Physics and Astronomy, University of California) ;
  • Wada, Takehiko (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency) ;
  • Ohyama, Youichi (Academia Sinica, Institute of Astronomy and Astrophysics) ;
  • Kataza, Hirokazu (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency) ;
  • Takita, Satoshi (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency) ;
  • Yamauchi, Chisato (Misato Observatory)
  • Received : 2015.07.13
  • Accepted : 2016.10.25
  • Published : 2017.03.31
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Abstract

We demonstrate the luminosity dependence of the covering factor (CF) of active galactic nuclei (AGNs), based on AKARI mid-infrared all-sky survey catalog. Combining the AKARI with Sloan Digital Sky Survey (SDSS) spectroscopic data, we selected 243 galaxies at $9{\mu}m$ and 255 galaxies at $18{\mu}m$. We then identified 64 AGNs at $9{\mu}m$ and 105 AGNs at $18{\mu}m$ by their optical emission lines. Following that, we estimated the CF as the fraction of type 2 AGN in all AGNs. We found that the CF decreased with increasing $18{\mu}m$ luminosity, regardless of the choice of type 2 AGN classification criteria.

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References

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