SIMBAD references

To investigate the origin of the dependence of the covering factor on the Eddington ratio suggested by X-ray observations, we examined the angular distribution of H I and H II based on two-dimensional radiative hydrodynamic simulations. To calculate the Compton-thin covering factor C₂₂ and Compton-thick covering factor C₂₄ of H I alone, we performed one-dimensional photoionization equilibrium calculations with the XSTAR code based on radiative hydrodynamic simulations. The results obtained are as follows. (1) The Compton-thin covering factor C₂₂ of H I and H II is independent of the Eddington ratio and is approximately 70%, while C₂₂ of H I alone is also independent of the Eddington ratio and is approximately 30%. (2) The Compton-thick covering factor C₂₄ of H I has the same value as C₂₂ of H I. (3) Our C₂₄ is consistent with that obtained from X-ray observations. (4) Our C₂₂ agrees with that obtained from X-ray observations in a high Eddington ratio, while our C₂₂ is smaller than that from X-ray observations in a low Eddington ratio. (5) To explain the difference between C₂₂ obtained from theoretical calculations and that inferred from X-ray observations, a Compton-thin gas is required in regions extending at least 10 pc beyond the current computational regions.