Variable X-ray Absorption in the Mini-broad Absorption Line Quasar PG 1126-041

We present the results of a multi-epoch observational campaign on the mini-broad absorption line quasar (mini-BAL QSO) PG 1126-041 performed with XMM-Newton from 2004 to 2009. Time-resolved X-ray spectroscopy and simultaneous UV and X-ray photometry were performed on the most complete set of observations and on the deepest X-ray exposure of a mini-BAL QSO to date. Complex X-ray spectral variability, found on time scales of both months and hours, is best reproduced by means of variable and massive ionized absorbers along the line of sight. In the highest signal-to-noise observation, highly-ionized X-ray absorbing material outflowing much faster (υ_out∼ 16500 km s^-1) than the UV absorbing one (υ_out∼ 5000 km s^-1) is detected. This highly-ionized absorber is found to be variable on very short time scales of a few hours.