X-ray Evidence for Multiple Absorbing Structures in Seyfert Galaxies
نویسنده
چکیده
We have used X-ray spectra to measure attenuating columns in a large sample of Seyfert galaxies. Over 30 of these sources have resolved radio jets, allowing the relative orientation of the nucleus and host galaxy to be constrained. We have discovered that the distribution of absorbing columns is strongly correlated with the relative orientation of the Seyfert structures. This result is inconsistent with unification models having only a torus and is instead most readily explained if a second absorber is included: in addition to a Compton-thick torus there would also be a larger-scale absorber with NH < 10 23 cm. The second absorber is aligned with the host galactic plane while the torus is arbitrarily misaligned.
منابع مشابه
X-ray Evidence for Multiple Absorbing Structures in Seyfert Nuclei
We have discovered a correlation between the X-ray absorbing column densities within Seyfert galaxies and the relative alignment between the central engines and their host galactic disks. This correlation carries several implications for Seyfert unification models. (1) In addition to small-scale circumnuclear absorbers, there are absorbing systems associated with the host galactic plane that ar...
متن کاملar X iv : a st ro - p h / 97 08 23 1 v 1 2 5 A ug 1 99 7 ASCA observations of type - 2 Seyfert Galaxies : III Orientation and X - ray Absorption
We discuss the spectral properties of a sample of type-2 Seyfert galaxies based upon the analysis of ASCA data. In this paper we consider the sources for which the X-ray spectra appear to be dominated by the nuclear continuum, transmitted through a large column of absorbing material. We find that both Seyfert-2 galaxies and NELGs show iron Kα line profiles indicative of reprocessing of nuclear ...
متن کاملThe Chandra High Energy Transmission Grating Observation of an X - ray Ionization Cone in Markarian 3
We present a preliminary analysis of the first high-resolution X-ray spectrum of a Seyfert 2 galaxy, Mkn 3, obtained with the High Energy Transmission Grating Spectrometer onboard the Chandra X-ray Observatory. The high-energy spectrum (λ . 4 Å) is dominated by reflection of the AGN continuum radiation in a cold optically thick medium and contains bright Kα fluorescent lines from iron and silic...
متن کامل54 2 v 1 2 9 N ov 2 00 0 Variable X - ray Absorption in the Seyfert 2 Galaxy Mrk 348
We present RXTE monitoring observations of the Seyfert 2 galaxy Mrk 348 spanning a 6 month period. The time-averaged spectrum in the 3–20 keV band shows many features characteristic of a Compton-thin Seyfert 2 galaxy, namely a hard underlying power-law continuum (Γ ≈ 1.8) with heavy soft X-ray absorption (NH ∼ 10 23 cm) plus measureable iron Kα emission (equivalent width ∼ 100 eV) and, at high ...
متن کاملThe Effect of Intrinsic UV Absorbers on the Ionizing Continuum and Narrow Emission Line Ratios in Seyfert Galaxies
We explore the effects of UV absorbing material on the shape of the EUV continuum radiation emitted by the active galactic nucleus, and on the relative strengths of emission lines, formed in the narrow line regions of Seyfert galaxies, excited by this continuum. Within a sample of Seyfert 1.5 galaxies, objects with flatter soft X-ray slopes tend to have lower values of He II λ4686/Hβ, which imp...
متن کامل