X-ray spectra of the Narrow-Line Seyfert 1 Galaxy Ton S180 in comparison with galactic black holes

Mio Murashima, Aya Kubota, Kazuo Makishima, Motohide Kokubun, Soojing Hong, Hitoshi Negoro

Research output: Contribution to journalArticle

5 Citations (Scopus)


An analysis was made of 0.3-15 keV X-ray spectra of a Narrow-Line Seyfert 1 Galaxy, Ton S180, using archival data from ASCA, RXTE, and XMM-Newton. At energies above 2.5 keV, a power-law with a photon index of ∼ 2.3 successfully and consistently reproduced the spectra from all of these observatories. Assuming this powerlaw component to extend toward lower energies, a soft excess, which is one of the most remarkable features of Narrow-Line Seyfert 1 Galaxies, is explained by another power-law multiplied by a thermal cutoff at ∼ 0.4 keV. Some similarities have been observed between this object and Galactic black hole binaries in very high state, the latter being realized under high accretion rates. Attempts have been made to interpret the soft excess in terms of Comptonization of the disk photons by an electron cloud surrounding the accretion disk, like BHBs in a very high state.

Original languageEnglish
Pages (from-to)279-285
Number of pages7
JournalPublications of the Astronomical Society of Japan
Issue number2
Publication statusPublished - 2005 Jun 1



  • Accretion, accretion disks
  • Galaxies: Seyfert
  • X-rays: individual (Ton S180)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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