Evidence for relativistic outflows in narrow-line Seyfert 1 galaxies

We report the observation of features near 1 keV in the Xray spectra from three Narrow-Line Seyfert 1 (NLS1) galaxies obtained using the ASCA satellite. We interpret these as oxygen absorption features in a highly relativistic outflow. If due to continuum absorption, the implied ejection 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 (BAL QSOs), but with larger velocities, and we note the remarkable similarities in the optical emission line and broad band properties of NLS1s and low-ionization BAL QSOs.