The Ionization Structure of a Nebula Photoionized by a Flat Spectrum
Abstract
Analytic approximations are developed in this paper for the ionization structure of a medium that is photoionized by a flat spectrum. The presence of a diffuse ionization zone depends on the precise form of the ultraviolet ionization spectrum. For a photon number spectrum that falls off as -1 there is a diffuse ionization structure and for a spectrum that falls off like v- there is a more classical Stro. mgren-like behavior with a halfwidth an order of magnitude smaller than in the v-1 case. The basic equations are also presented for a more general class of spectral indices as well as a power law behavior of the total density on distance from the ionization source. Key words: photoionization - flat spectrum - Seyfert galaxies - quasars - spectral index.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- June 1971
- Bibcode:
- 1971A&A....13....1B