Evidence for relativistic outflows in narrow-line Seyfert 1 galaxies

We report the observation of features near 1 keV in the ASCA spectra from three narrow-line Seyfert 1 (NLS 1) galaxies. We interpret these as oxygen absorption in a highly relativistic outflow. If interpreted as absorption edges, the implied velocities are 0.2-0.3 c, near the limit predicted by ''line-locking'' radiative acceleration. If instead interpreted as broad absorption lines, the implied velocities are similar to 0.57 c, interestingly near the velocity of particles in the last stable orbit around a Kerr black hole, although a physical interpretation of this is not obvious. The features are reminiscent of the UV absorption lines seen in broad absorption Line quasars (BALQSOs), but with larger velocities, and we note the remarkable similarities in the optical emission line and broadband properties of NLS1s and low-ionization BALQSOs.