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

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 −1 . 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.

Upholding the unified model for active galactic nuclei: VLT/FORS2 spectropolarimetry of Seyfert 2 galaxies

“…Finally, for the three galaxies whose fits do not require scattered broad components (NGC 5506, NGC 5643, and NGC 5728) we cannot discard the presence of a HBLR, but from the spectra presented here, broad components are not necessary to reproduce the line profiles in polarized flux. Perhaps the presence of two or more kinematic components in these galaxies prevents the detection of faint and broad lines (Nagar et al 2002;Son et al 2009;Cresci et al 2015). Higher S/N observations than those presented here of a complete sample of Sy2 galaxies are required to either confirm or discard the ubiquitous existence of a HBLR in this type of AGN.…”

Quasar outflows at z ≥ 6: the impact on the host galaxies

“…AGN outflows can overpressure and compress clumpy gas clouds, triggering starbursts, as have been shown in theoretical and numerical studies (e.g., De Young 1989;Silk 2005;Zubovas et al 2013), including cold molecular clumps condensing out in quasar outflows (Ferrara & Scannapieco 2016). Positive feedback has been observed in jet-induced star formation and radiooptical alignment (e.g., Chambers, Miley & van Breugel 1987;Zinn et al 2013), as well as in Seyfert-like radio-quiet AGN (Cresci et al 2015).…”

A free-form mass model of the Hubble Frontier Fields cluster AS1063 (RXC J2248.7−4431) with over one hundred constraints

“…AGN-driven nuclear ionized outflows are ubiquitous in the most massive star-forming galaxies at high redshift (Genzel et al 2014). This high duty cycle phenomenon is a prime candidate for triggering of star formation due to a narrow ionization cone or jet as observed by Cresci et al (2015). We cite two other examples suggestive of triggering by positive feedback.…”