At the edge of an AGN wind: a deep observation of PG 1126-041

PG 1126041 is a low redshift BAL QSO which shows strong Xray variability both in flux and spectral shape, on timescales of both years and hours. Previous Xray observations, though limited in S/N, strongly suggest variablewarm absorption as the cause of the observed spectral variability. A long andcontinuous XMMNewton observation of PG 1126041 will allow us to accuratelymeasure physical parameters, and their variations with time, like intrinsiccontinuum luminosity and photon index, warm absorber column density, ionizationparameter, covering fraction, and the physical link among them. The combination of the presence of a clear and powerful UV outflow with the variability of theXray warm absorber makes PGvirgul1126041 a unique case study for quasar outflows. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]