Poster Presentation

Variability of BAL QSOs from SDSS

Weihao, Bian & Zhichen, He

BAL troughs in BAL QSOs are thought to be the strongest observed signatures of QSOs wind. The variability of BAL troughs from SDSS provides very important clues to the origin of the wind. Two kinds of methods are used，one is to use two-epoch spectra in a BAL sample, the other is to use multi-epoch spectra for one single object.
For BAL QSO, SDSS J022844.09+000217.0 (z = 2.719) with 18 SDSS/BOSS spectra covering 4128 d in the observed frame, we found that there is a strong correlation between the BAL-trough EW and the spectral index and a weak negative correlation between the BAL-trough EW and the continuum luminosity. The results suggest that dust is intrinsic to outflows, and the BAL-trough variation is not dominated by photoionization. The BAL variability for a SDSS sample is also briefly discussed.