Optical spectroscopy of two broad absorption line QSOs and implications for spherical symmetric absorbing wind models.

The results of low-resolution observations of two broad absorption line QSOs in the wavelength range from 3200 A to 1 micron are discussed. The spectrum of the first QSO (Q1101 + 091) is found to have a complex structure. An approximate redshift of 2.27 was obtained on the basis of the Mg II (2798 A) emission line, and a redshift emission of 2.546 (+ or -0.003) A was obtained for the second QSO (Q1413 + 117) from several different lines. An estimate is derived for the product of the QSO mass loss rate and the mean Si(3+)/Si fraction by applying a moments method first developed by Castor et al. (1981) for Q1413 + 117. The derived estimate is compared with results of ionization and thermal equilibrium calculations carried out for a variety of stellar wind and QSO parameters. It is shown that the spherically-symmetric wind model is only viable for QSOs emitting weakly at X-ray energies and that the mass loss rate needs to be at least 40 solar mass per year. Some of the consequences of this finding for the thermal stability of the stellar wind are discussed.