The ionized gas outflow in the Circinus galaxy: kinematics and physical conditions

MARCOS FONSECA FARIA; VICTORIA REYNALDI; ALBERTO RODRÍGUEZ ARDILA; MARCELLA CONTINI

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021 vol. 506 p. 3831 - 3852

0035-8711

We employ MUSE/VLT data to study the ionised and highly ionised gas phases of the feedbackin Circinus, the closest Seyfert 2 galaxy to us. The analysis of the nebular emission allowed us todetect a remarkable high-ionisation gas outflow beyond the galaxy plane traced by the coronallines [Fe vii] λ6089 and [Fe x] λ6374, extending up to 700 pc and 350 pc NW from the nucleus,respectively. This is the first time that the [Fe x] emission is observed at such distances fromthe central engine in an AGN. The gas kinematics reveals expanding gas shells with velocities−1of a few hundred km s , spatially coincident with prominent hard X-ray emission detected byChandra. Density and temperature sensitive line ratios show that the extended high-ionisation−3gas is characterized by a temperature reaching 25000 K and an electron density > 102 cm .We found that local gas excitation by shocks produced by the passage of a radio jet leadsto the spectacular high-ionisation emission in this object. This hypothesis is fully supportedby photoionisation models that accounts for the combined effects of the central engine andshocks. They reproduce the observed emission line spectrum at different locations inside andoutside of the NW ionisation cone. The energetic outflow produced by the radio jet is spatiallylocated close to an extended molecular outflow recently reported using ALMA which suggeststhat they both represent different phases of the same feedback process acting on the AGN.