48 citations · 233 across the 13 of their papers we have counts for
13 papers
Wind Acceleration as a Driver of Detached Blueshifted Absorption in Quasar Disk Winds
Randall C. Dannen, Daniel Proga, Paola Rodríguez Hidalgo +4
Active galactic nuclei (AGN) unification models often emphasize the viewing angle, , but alone does not determine quasar properties. This is crucial for quasar outflows: UV…
Flux-Averaged Force Multipliers
Sergei Dyda, Randall C. Dannen, Shane W. Davis +2
We apply novel developments in photoionization modeling and multi-frequency radiation hydrodynamics to the study of line driven AGN disc winds. We use a flux-averaged force multipl…
Time-Dependent AGN Disc Winds II -- Effects of Photoionization
Sergei Dyda, Randall C. Dannen, Timothy R. Kallman +2
We use a combination of radiation hydrodynamics (rad-HD) and photoionization modeling to study line-driven disc winds for a range of black hole masses. We refined previous models b…
Oscillatory Line-Driven Winds: The Role of Atmospheric Stratification
Joshua Key, Daniel Proga, Randall Dannen +2
Time-dependent numerical studies of line-driven winds using the Sobolev approximation have a history spanning over three decades. In many of these studies, the wind solutions displ…
Position dependent radiation fields near accretion disks
Kara Smith, Daniel Proga, Randall Dannen +2
In disk wind models for active galactic nuclei (AGN) outflows, high-energy radiation poses a significant problem wherein the gas can become overionized, effectively disabling what…
On the transition from efficient to inefficient line-driving in irradiated flows
Randall Dannen, Daniel Proga, Tim Waters
Observations of ionized AGN outflows have provided compelling evidence that the radiation field transfers both momentum and energy to the plasma. At parsec scale distances in AGN,…
Dynamical thermal instability in highly supersonic outflows
Tim Waters, Daniel Proga, Randall Dannen +1
Acceleration can change the ionization of X-ray irradiated gas to the point that the gas becomes thermally unstable. Cloud formation, the expected outcome of thermal instability (T…
On Synthetic Absorption Line Profiles of Thermally Driven Winds from Active Galactic Nuclei
Shalini Ganguly, Daniel Proga, Tim Waters +7
The warm absorbers observed in more than half of all nearby active galactic nuclei (AGN) are tracers of ionized outflows located at parsec scale distances from the central engine.…
Multiphase AGN winds from X-ray irradiated disk atmospheres
Tim Waters, Daniel Proga, Randall Dannen
The mechanism of thermal driving for launching mass outflows is interconnected with classical thermal instability (TI). In a recent paper, we demonstrated that as a result of this…
Clumpy AGN outflows due to thermal instability
Randall Dannen, Daniel Proga, Tim Waters +1
One of the main mechanisms that could drive mass outflows on parsec scales in AGN is thermal driving. The same X-rays that ionize and heat the plasma are also expected to make it t…
Photoionization calculations of the radiation force due to spectral lines in AGNs
Randall C. Dannen, Daniel Proga, Timothy R. Kallman +1
One of the main mechanisms that could drive mass outflows in AGNs is radiation pressure due to spectral lines. Although straightforward to understand, the actual magnitude of the r…
Synthetic absorption lines for a clumpy medium: a spectral signature for cloud acceleration in AGN?
Tim Waters, Daniel Proga, Randall Dannen +1
There is increasing evidence that the highly ionized multiphase components of AGN disk winds may be due to thermal instability. The ions responsible for forming the observed X-ray…
Irradiation of Astrophysical Objects - SED and Flux Effects on Thermally Driven Winds
Sergei Dyda, Randall Dannen, Tim Waters +1
We develop a general method for the self consistent calculation of the hydrodynamics of an astrophysical object irradiated by a radiation field with an arbitrary strength and spect…