The new primary X-ray component confirmed in the Seyfert i galaxy IC 4329A

Katsuma Miyake, Hirofumi Noda, Shin'Ya Yamada, Kazuo Makishima, Kazuhiro Nakazawa

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2 Citations (Scopus)


The bright and highly variable Seyfert I active galactic nucleus IC 4329A was observed with Suzaku five times in 2007 August, with intervals of ∼5 days and a net exposure of 24-31 ks each. Another longer observation was carried out in 2012 August with a net exposure of 118 ks. In the six observations, a source was detected in 2-45 keV with an average 2-10 keV fluxes of (0.67-1.2) × 10-10 erg cm-2 s-1. Its intensity changed by a factor of 2 among the five observations in 2007, and 1.5 within the 2012 observation. A difference of spectrum among these observations revealed that the variability of IC 4329A was carried mainly by a power-law component with a photon index Γ ∼ 2.0. However, in addition to this primary component and its associated reflection, the broad-band Suzaku data required another, harder, and less-variable component with Γ ∼ 1.4. The presence of this new continuum was also confirmed by analyzing the same six data sets through the spectral decomposition technique developed by Noda et al. (2013a, ApJ, 771, 100). This Γ ∼ 1.4 continuum is considered to be a new primary component that has not been recognized in the spectra of IC 4329A so far, although it was recently identified in those of several other Seyfert I galaxies (Noda et al. 2013a, ApJ, 771, 100; Noda et al. 2014, ApJ, 794, 2).

Original languageEnglish
Article numberS28
JournalPublications of the Astronomical Society of Japan
Publication statusPublished - 2016 Jun 1


  • X-rays: galaxies
  • galaxies: Seyfert
  • galaxies: active
  • galaxies: individual (IC 4329A)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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