Journal Article

The influence of soft spectral components on the structure and stability of warm absorbers in active galactic nuclei

Susmita Chakravorty, Ranjeev Misra, Martin Elvis, Ajit K. Kembhavi and Gary Ferland

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 422, issue 1, pages 637-651
Published in print May 2012 | ISSN: 0035-8711
Published online April 2012 | e-ISSN: 1365-2966 | DOI: http://dx.doi.org/10.1111/j.1365-2966.2012.20641.x
The influence of soft spectral components on the structure and stability of warm absorbers in active galactic nuclei

More Like This

Show all results sharing this subject:

  • Astronomy and Astrophysics

GO

Show Summary Details

Preview

The radiation from the central regions of active galactic nuclei, including that from the accretion disc surrounding the black hole, is likely to peak in the extreme-ultraviolet ∼13–100 eV. However, due to Galactic absorption, we are limited to constrain the physical properties, i.e. the black hole mass and the accretion rate, from what observations we have below ∼10 eV or above ∼100 eV. In this paper, we predict the thermal and ionization states of warm absorbers as a function of the shape of the unobservable continuum. In particular we model an accretion disc at kTin∼ 10 eV and a soft excess at kTse∼ 150 eV. The warm absorber, which is the highly ionized gas along the line of sight to the continuum, shows signatures in the ∼0.3–2 keV energy range consisting of numerous absorption lines and edges of various ions, some of the prominent ones being H- and He-like oxygen, neon, magnesium and silicon. We find that the properties of the warm absorber are significantly influenced by the changes in the temperature of the accretion disc, as well as by the strength of the soft excess, as they affect the optical depth particularly for iron and oxygen. These trends may help develop a method of characterizing the shape of the unobservable continuum and the occurrence of warm absorbers.

Keywords: galaxies: active; quasars: absorption lines; galaxies: Seyfert; X-rays: galaxies; X-rays: ISM

Journal Article.  11362 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.