A polar plus equatorial wind model for broad absorption line quasars I. Fitting the C IV BAL profiles

作者：Borguet B; Hutsemekers D

来源：Astronomy & Astrophysics, 2010, 515: A22.

DOI：10.1051/0004-6361/200913255

• quasars: absorption lines
• radiative transfer
• methods: numerical

Context. Despite all the studies, the geometry of the wind at the origin of the blueshifted broad absorption lines (BAL) observed in nearly 20% of quasars still remains a matter of debate.
Aims. We want to see if a two-component polar+equatorial wind geometry can reproduce the typical BAL profiles observed in these objects.
Methods. We built a Monte Carlo radiative transfer code (called MCRT) to simulate the line profiles formed in a polar+equatorial wind in which the photons, emitted from a spherically symmetric core are resonantly scattered. Our goal is to reproduce typical C IV line profiles observed in BAL quasars and to identify the parameters governing the line profiles.
Results. The two-component wind model appears to be efficient in reproducing the BAL profiles from the P Cygni-type profiles to the more complex ones. Some profiles can also be reproduced with a pole-on view. Our simulations provide evidence of a high-velocity rotation of the wind around the polar axis in BAL quasars with non P Cygni-type line profiles.

• 出版日期2010-6