The Suzaku view of highly-ionised outflows in AGN: I - Statistical detection and global absorber properties. (arXiv:1211.5810v1 [astro-ph.HE])

The Suzaku view of highly-ionised outflows in AGN: I - Statistical detection and global absorber properties. (arXiv:1211.5810v1 [astro-ph.HE]):
We present the results of a new spectroscopic study of Fe K-band absorption
in Active Galactic Nuclei (AGN). Using data obtained from the Suzaku public
archive we have performed a statistically driven blind search for Fe XXV Hea
and/or Fe XXVI Lyb absorption lines in a large sample of 51 type 1.0-1.9 AGN.
Through extensive Monte Carlo simulations we find statistically significant
absorption is detected at E>6.7 keV in 20/51 sources at the P(MC)>95% level,
which corresponds to ~40% of the total sample. In all cases, individual
absorption lines are detected independently and simultaneously amongst the two
(or three) available XIS detectors which confirms the robustness of the line
detections. The most frequently observed outflow phenomenology consists of two
discrete absorption troughs corresponding to Fe XXV Hea and Fe XXVI Lyb at a
common velocity shift. From xstar fitting the mean column density and
ionisation parameter for the Fe K absorption components are log(NH/cm^{-2})~23
and log(xi/erg cm s^{-1})~4.5, respectively. Measured outflow velocities span a
continuous range from <1,500 km/s up to ~100,000 km/s, with mean and median
values of ~0.1c and ~0.056c, respectively. The results of this work are
consistent with those recently obtained using XMM-Newton and independently
provides strong evidence for the existence of very highly-ionised circumnuclear
material in a significant fraction of both radio-quiet and radio-loud AGN in
the local universe.