A spectacular outflow in an obscured quasar

TL;DR

This paper reports the discovery of symmetric, high-velocity outflows from an obscured quasar in a merging galaxy system, providing evidence for radio-quiet quasar feedback mechanisms.

Contribution

It presents the first detailed kinematic model of large-scale outflows in a radio-quiet quasar, highlighting their energetic impact on the host galaxy.

Findings

Outflows extend ~10 kpc from the nucleus.

Deprojected velocities are likely ~1000 km/s.

Kinetic energy of outflows is estimated at 10^44-10^45 erg/s.

Abstract

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.