A broad-line quasar with unexplained extreme velocity offsets: post-shock outflow?

The quasar SDSS 0956+5128 exhibits three distinct velocity components with large offsets in emission: the systemic velocity of [O II], [O III] and [Ne III] narrow lines have redshift z=0.7142; broad Mg II line is shifted by -1200 km s^{-1} with respect to the narrow lines; broad H\alpha, H\beta lines... Show more