Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (546) (Citation History)
· Refereed Citations to the Article
· Also-Read Articles (Reads History)
· Translate This Page
A two-phase model for the X-ray emission from Seyfert galaxies
Haardt, F.; Maraschi, L.
AA(Milano, Università, Milan, Italy), AB(Milano, Università, Milan, Italy)
Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 380, Oct. 20, 1991, p. L51-L54. (ApJL Homepage)
Publication Date:
NASA/STI Keywords:
Accretion Disks, Astronomical Models, Emission Spectra, Seyfert Galaxies, X Ray Spectra, Computational Astrophysics, Galactic Nuclei, Gravitational Effects, Interstellar Magnetic Fields, Magnetic Field Reconnection
Bibliographic Code:


Attention is given to a two-phase accretion disk model, with emphasis on thermal Comptonization as the basic mechanism for producing the X-ray power-law continuum of Seyfert galaxies within the framework of the new picture of the inner emission region. A substantial fraction, f, of the gravitational power is assumed to be dissipated via buoyancy and reconnection of the magnetic fields in a hot tenuous 'corona' surrounding the disk's main body. Coupled thermal balance equations for the two phases yield the temperature of the hot phase and the slope of the Comptonized component self-consistently as a function of f and tau, the optical depth of the hot phase. It is found that for f approximately equal to 1 and tau less than 1, the temperature of the hot phase adjusts so as to maintain alpha approximately equal to 1. For small tau the temperature of the hot phase is sufficient for the production of electron-positron pairs to be important. Pair production contributes to the optical depth and limits the maximum temperature allowed.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)


Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints