Abstract
We report two new XMM-Newton observations of PG1211+143 in December 2007, again finding evidence of the fast outflow of highly ionised gas first detected in 2001. Stacking the new spectra with those from two earlier XMM-Newton observations reveals strong and broad emission lines of FeXXV and OVIII, indicating the fast outflow to be persistent and to have a large covering factor. This finding confirms a high mass rate for the ionised ouflow in PG1211+143 and provides the first direct measurement of a wide angle, sub-relativistic outflow from an AGN transporting mechanical energy with the potential to disrupt the growth of the host galaxy. We suggest PG1211+143 may be typical of an AGN in a rapid super-Eddington growth phase.
Highlights
An early XMM–Newton observation of the bright quasi-stellar object PG1211+143 in 2001 provided strong evidence of a radial outflow of highly ionized gas with the remarkably high velocity of ∼0.13c (Pounds et al 2003; Pounds & Page 2006)
The broader potential importance of such energetic flows, which we have suggested might be typical of active galactic nuclei (AGN) accreting at the Eddington rate (King & Pounds 2003, hereafter K03), is in offering a feedback mechanism that could link the growth of supermassive black holes in AGN with their host galaxy (Ferrarese & Merritt 2000; Gebhardt et al 2000; Tremaine et al 2002; King 2003; Kim et al 2008)
A significant, but variable strength absorption line has been observed at ∼7 keV in three of the four XMM–Newton observations of PG1211+143, and in an observation from Suzaku (Reeves et al 2008)
Summary
An early XMM–Newton observation of the bright quasi-stellar object PG1211+143 in 2001 provided strong evidence of a radial outflow of highly ionized gas with the remarkably high velocity of ∼0.13c (Pounds et al 2003; Pounds & Page 2006). Unless viewed along the axis of a highly collimated flow, the high column density required to produce the observed Fe K absorption, combined with the high velocity, implied a mass outflow rate comparable to the accretion rate and transporting mechanical energy at a significant fraction of the bolometric luminosity. The greatly improved sensitivity of current X-ray observations in the Fe K energy band is yielding more examples of highly ionized outflows with large column densities and high velocities (see Cappi 2006 for a recent review), but the lack of information on the outflow collimation and covering factors (CFs) has left large uncertainties in the total mass and energy of these flows (Elvis 2006).
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