Extreme Gaseous Outflows in Radio-Loud Narrow-Line Seyfert 1 Galaxies
  We present four radio-loud NLS1 galaxies with extreme emission-line shifts,
indicating radial outflow velocities of the ionized gas of up to 2450 km/s,
above the escape velocity of the host galaxies. The forbidden lines show strong
broadening, up to 2270 km/s. An ionization stratification (higher line shift at
higher ionization potential) implies that we see a large-scale outflow rather
than single, localized jet-cloud interactions. Similarly, the paucity of
zero-velocity [OIII]$\lambda$5007 emitting gas implies the absence of a second
narrow-line region (NLR) component at rest, and therefore a large part of the
high-ionization NLR is affected by the outflow. Given the radio loudness of
these NLS1 galaxies, the observations are consistent with a pole on view onto
their central engines, so that the effects of polar outflows are maximized. In
addition, a very efficient driving mechanism is required, to reach the high
observed velocities. We explore implications from recent hydrodynamic
simulations of the interaction between fast winds or jets with the large-scale
NLR. Overall, the best agreement with observations (and especially the high
outflow speeds of the [NeV] emitting gas) can be reached if the NLS1 galaxies
are relatively young sources with lifetimes not much exceeding 1 Myr. These
systems represent sites of strong feedback at NLR scales at work, well below
redshift one.
