Kavli Affiliate: Feng Yuan
| First 5 Authors: Weixiao Wang, De-Fu Bu, Feng Yuan, ,
| Summary:
Winds are commonly observed in luminous active galactic nuclei (AGNs). A
plausible model of those winds is magnetohydrodynamic (MHD) disc winds. In the
case of disc winds from a thin accretion disc, isothermal or adiabatic
assumption is usually adopted in such MHD models. In this work we perform
two-dimensional MHD simulations implementing different thermal treatments
(isothermal, adiabatic and radiative) to study their effects on winds from a
thin accretion disc. We find that both the isothermal model and the adiabatic
model overestimate the temperature, underestimate the power of disc winds, and
cannot predict the local structure of the winds, compared to the results
obtained by solving the energy equation with radiative cooling and heating.
Based on the model with radiative cooling and heating, the ionization
parameter, the column density and the velocity of the disc winds have been
compared to the observed ultrafast outflows (UFOs). We find that in our
simulations the UFOs can only be produced inside hundreds of Schwarzschild
radius. At much larger radii, no UFOs are found. Thus, the pure MHD winds
cannot interpret all the observed UFOs.
| Search Query: ArXiv Query: search_query=au:”Feng Yuan”&id_list=&start=0&max_results=10