On the Distances and Energetics of AGN Outflows

Active galactic nuclei (AGN) ubiquitously show outflows. It is now widely recognized that these outflows are key components in the evolution of super-massive black holes and their host galaxies. As important as these outflows are, we still lack sufficient understanding of their structure and energetics. The majority of the work presented in this thesis involved photoionization modeling of AGN outflows along with analysis of density diagnostics in order to determine the distances and energetics of observed outflows. The main findings of these analyses are that 1) outflows are often at distances of hundreds to thousands of parsecs from the central supermassive black hole and 2) quasars outflows can be sufficiently powerful to provide feedback in galactic evolution scenarios. We also find in some cases that the recombination timescales of metal ions are long compared with the flux variability timescales. The large distances we find provide a challenge to current outflow models. For example, these outflows cannot be connected with an accretion disk surrounding the supermassive black hole as assumed in some models. Furthermore, the outflows may be out of equilibrium as we find in Mrk 509. In this case, a thorough understanding of time-dependent photoionization effects is necessary. In this thesis, I include early steps toward understanding time-dependent photoionization as well as ionization studies of accretion disk winds. The main results of these theoretical studies is that 1) the appearance of multiple ionization components in an outflow can be an artifact of the incorrect assumption that the outflow is in ionization equilibrium and 2) the shielding gas required in accretion-disk-wind models should have a clear signature in UV spectra, but none has been observed to date.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Physics

Department dc:contributor.department

Physics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2013

Author dc:creator

• Edmonds, Bartlett D.

Chair dc:contributor.committeechair

• Arav, Nahum

Committee members dc:contributor.committeemember

• Sharpe, Eric R.
• Pitt, Mark L.
• Simonetti, John H.

• Active galactic nuclei
• AGN outflows
• Quasar
• Quasar outflow
• Seyfert galaxies

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:1594

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/23767