How do we see the nuclear region (r<0.1 pc) of narrow-line Seyfert 1 galaxies?

Takashi Murayama, Tohru Nagao, Yoshiaki Taniguchi

Research output: Contribution to journalReview articlepeer-review

1 Citation (Scopus)

Abstract

We propose two statistical tests to investigate how we see the nuclear region (r<0.1 pc) of narrow-line Seyfert 1 galaxies (NLS1s). 1) The high-ionization nuclear emission-line region (HINER) test: Seyfert 1 galaxies (S1s) have systematically higher flux ratios of [FeVII] λ6087 to [OIII] λ5007 than Seyfert 2 galaxies (S2s). This is interpreted in that a significant part of the [FeVII] λ6087 emission arises from the inner walls of dusty tori that cannot be seen in S2s [Murayama, T., Taniguchi, Y., 1998a. ApJ 497, L9; 1998b. ApJ 503, L115]. 2) The mid-infrared test: S1s have systematically higher flux ratios of the L band (3.5 μm) to the IRAS 25 μm band than S2s. This is also interpreted in that a significant part of the L band emission arises from the inner walls of dusty tori, because the tori are optically thick enough to absorb the L band emission if the tori are viewed nearly edge on [Murayama, T. et al., 2000. ApJ 528, 179]. Applying these tests to a sample of NLS1s, we have found that the NLS1s possibly have nearly the same properties as S1s.

Original languageEnglish
Pages (from-to)447-449
Number of pages3
JournalNew Astronomy Reviews
Volume44
Issue number7-9
DOIs
Publication statusPublished - 2000 Sep

Keywords

  • Galaxies: Seyfert
  • Galaxies: active
  • Galaxies: nuclei
  • Infrared radiation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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