Skip to main content Accessibility help
×
  1. Home
  2. Search

Refine search

Refine search

Access:
Content type:
Publication date:
Apply   From and To filters
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Save to Kindle
  • Save to Dropbox
  • Save to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

1 results

  • 18 - Active Black Holes and Eddington

  • from Part Three - Galaxies and Their Gas
  • Christopher W. Churchill, New Mexico State University
  • Book:
    Quasar Absorption Lines
    Published online:
    10 December 2025
    Print publication:
    18 December 2025, pp 621-654

  • Summary

    Black holes were hypothesized as far back as the 1770s, but were not theoretically formalized until 1916, nor observationally identified until the 1970s. Since then, they have been recognized as a ubiquitous and important component of galaxy evolution and the baryon cycle. At the heart of AGN/quasars, they generate powerful outflows, which are believed to be radiatively driven. The nature of these outflows depends on the luminosity generated by the black hole accretion disks and the radiative efficiency of the accretion process. The luminosity is characterized by the Eddington ratio, the ratio of the bolometric luminosity to the Eddington luminosity, which is the value at which radiation pressure propels infalling gas outward. Quasars are observed to have a Schechter function distribution of Eddington ratios. Based on arguments of force multipliers, the case for radiative line-driven winds is advanced. A simplified picture in which outflows can be predicted on a plot of Eddington ratio versus black hole mass is discussed, as well as a black hole evolution H-R type of diagram based on “downsizing.”