The MAGNUM survey: Positive feedback in the nuclear region of NGC 5643 suggested by MUSE

TL;DR

This study uses MUSE observations to analyze ionization and gas kinematics in NGC 5643's nucleus, revealing a double-sided ionization cone, nuclear outflows, and potential outflow-induced star formation, highlighting positive feedback in AGN-host galaxy interaction.

Contribution

First evidence of outflow-induced star formation in a Seyfert galaxy, linking nuclear outflows to positive feedback mechanisms affecting galaxy evolution.

Findings

Detection of a double-sided ionization cone.

Identification of nuclear outflows with velocities up to ~450 km/s.

Evidence for star formation triggered by outflow-induced gas compression.

Abstract

We study the ionization and kinematics of the ionized gas in the nuclear region of the barred Seyfert 2 galaxy NGC~5643 using MUSE integral field observations in the framework of the MAGNUM (Measuring Active Galactic Nuclei Under MUSE Microscope) survey. The data were used to identify regions with different ionization conditions and to map the gas density and the dust extinction. We find evidence for a double sided ionization cone, possibly collimated by a dusty structure surrounding the nucleus. At the center of the ionization cone, outflowing ionized gas is revealed as a blueshifted, asymmetric wing of the [OIII] emission line, up to projected velocity v(10)~-450 km/s. The outflow is also seen as a diffuse, low luminosity radio and X-ray jet, with similar extension. The outflowing material points in the direction of two clumps characterized by prominent line emission with spectra typical of HII regions, located at the edge of the dust lane of the bar. We propose that the star formation in the clumps is due to `positive feedback' induced by gas compression by the nuclear outflow, providing the first candidate for outflow induced star formation in a Seyfert-like radio quiet AGN. This suggests that positive feedback may be a relevant mechanism in shaping the black hole-host galaxy coevolution.