Suzaku Results on the Obscured Low-Luminosity Active Galactic Nucleus in NGC 4258

Abstract

In 2006 June, the obscured low luminosity active galactic nucleus in the nearby Seyfert 1.9 galaxy NGC 4258 was observed with Suzaku for ~ 100 ks. Utilizing the XIS and the HXD, the nucleus emission was detected over 2 to 40 keV range, with an unabsorbed 2--10 keV luminosity of 8 x 10 40 erg / s, and varied by a factor of ~ 2 during the observation. Its 2--40 keV spectrum is reproduced by a single power law with photon index of ~ 2.0, absorbed by an equivalent hydrogen column of ~ 1.0 x 10 23 cm2. The spectrum within 4' of the nucleus required also a softer thin-thermal emission, as well as an intermediate hardness component attributable to integrated point sources. A weak neutral Fe-Kalpha florescence line was detected at an equivalent width of ~ 40 eV. The cold reflection component was not required by the data, with the reflector solid angle Omega seen from the nucleus constrained as Omega / 2 pi < 0.3 assuming a general case of 60 deg inclination. The results suggest that the cold reflecting material around the nucleus is localized along our line of sight, rather than forming a thick torus.

PASJ, NGC4258, Suzaku, 12 pages, 11 figures

References in corpus (11)

• Hard X-ray Detector (HXD) on Board Suzaku
• Monte-Carlo Simulator and Ancillary Response Generator of Suzaku XRT/XIS System for Spatially Extended Source Analysis
• In-Orbit Performance of the Hard X-ray Detector on board Suzaku
• INTEGRAL observations of the cosmic X-ray background in the 5-100 keV range via occultation by the Earth
• Suzaku Observations of Active Galactic Nuclei Detected in the Swift/BAT Survey: Discovery of "New Type" of Buried Supermassive Black Holes
• Suzaku Results on Cygnus X-1 in the Low/Hard State
• Revealing the High Energy Emission from the Obscured Seyfert Galaxy MCG -5-23-16 with Suzaku
• Suzaku wide-band X-ray Spectroscopy of the Seyfert 2 AGN in NGC 4945
• An X-ray view of absorbed INTEGRAL AGN
• The Suzaku Observation of NGC 3516: Complex Absorption and the Broad and Narrow Fe K Lines
• Spatially resolved X-ray spectra of NGC 4258

Cited by in corpus (13)

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• Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei
• The INTEGRAL/IBIS AGN catalogue I: X-ray absorption properties versus optical classification
• Long-term X-Ray Spectral Variability in AGN from the Palomar sample observed by Swift
• Suzaku Studies of Wide-Band Spectral Variability of the Bright Type I Seyfert Galaxy Markarian 509
• New Compton-thick AGN in the circumnuclear water maser hosts UGC3 789 and NGC 6264
• X-ray spectra of hot accretion flows
• Nuclear Radio Jet from a Low-Luminosity Active Galactic Nucleus in NGC 4258
• On the role and origin of nonthermal electrons in hot accretion flows
• Suzaku Observation of the Metallicity in the Interstellar Medium of NGC 4258
• The flare model for X-ray variability of NGC 4258
• Hot accretion flows in low-luminosity active galactic nuclei in NGC 4258 and NGC 7213