Abstract
We build a bulk velocity-dependent photoionization model of the warm absorber of the Seyfert 1 galaxy NGC 3783. By adopting functional forms for the velocity of the flow and its particle density with radius, appropriate for radiation-driven winds, we compute the ionization, the temperature, the line Doppler shift, and the line optical depths as a function of distance. The model reproduces the observed relationship between the gas ionization and the velocity shift of the absorption line centroids in the X-ray spectrum of NGC 3783. The distribution of asymmetry seen in this spectrum requires the presence of two outflows: a higher ionization component responsible for the blue wings of the high ionization lines and the red wings of the low ionization oxygen lines, and a lower ionization flow that produces the blue wings of the oxygen lines.
