A spectacular outflow in an obscured quasar
  SDSS J1356+1026 is a pair of interacting galaxies at redshift z=0.123 that
hosts a luminous obscured quasar in its northern nucleus. Here we present two
long-slit Magellan LDSS-3 spectra that reveal a pair of symmetric ~10 kpc-size
outflows emerging from this nucleus, with observed expansion velocities of ~250
km/s in projection. We present a kinematic model of these outflows and argue
that the deprojected physical velocities of expansion are likely ~1000 km/s and
that the kinetic energy of the expanding shells is likely 10^44-10^45 erg/s,
with an absolute minimum of >10^42 erg/s. Although a radio counterpart is
detected at 1.4GHz, it is faint enough that the quasar is considered to be
radio-quiet by all standard criteria, and there is no evidence of extended
emission due to radio lobes, whether aged or continuously powered by an ongoing
jet. We argue that the likely level of star formation is probably insufficient
to power the observed energetic outflow and that SDSS J1356+1026 makes a strong
case for radio-quiet quasar feedback. In further support of this hypothesis,
polarimetric observations show that the direction of quasar illumination is
coincident with the direction of the outflow.
