Institution(s): 1. Columbus State Community College, 2. Ohio State University
Outflows are ubiquitous in AGNs, manifested by blueshifted absorption lines in the soft X-ray and UV bands and have outflow velocities of 100−1000 km s−1. The discovery of ultra-fast outflows (0.1 c) exhibited by blueshifted absorption lines in the hard X-ray band has added an intriguing aspect to the rich field of AGN outflows. The significance of these absorption line detections is often questioned and with only a few lines observed, accurate parametrization of the photoionized plasma becomes difficult. We recently discovered relativistic outflows in the soft X-ray band in two Seyfert galaxies; these detections are robust and alleviate earlier concerns about statistical significance of the lines in the hard X-ray band. I will discuss the our recent results on the discovery of high velocity outflows in the narrow line Seyfert 1 galaxies Ark 564 and Mrk 590. These absorbers are identified through multiple absorption lines at blueshift of 0.1c−0.17c detected in the Chandra HETG-MEG spectra. These high-velocity outflows have ionization parameter and column density typical of low-velocity outflows, but much higher velocity, probing a distinct region in the velocity versus ionization/column parameter space. The presence of such relativistic outflows in Seyfert galaxies poses a challenge to theoretical models of AGN winds. I will briefly discuss existing models and future prospects.