AGN-driven outflows and the AGN feedback efficiency in young radio galaxies

Abstract

Active galactic nuclei (AGN) feedback operated by the expansion of radio jets can play a crucial role in driving gaseous outflows on galaxy scales. Galaxies hosting young radio AGN, whose jets are in the first phases of expansion through the surrounding interstellar medium (ISM), are the ideal targets to probe the energetic significance of this mechanism. In this paper, we characterise the warm ionised gas outflows in a sample of nine young radio sources from the 2 Jy sample, combining X-shooter spectroscopy and Hubble Space Telescope imaging data. We find that the warm outflows have similar radial extents (∼0.06−2 kpc) as radio sources, consistent with the idea that “jet mode” AGN feedback is the dominant driver of the outflows detected in young radio galaxies. Exploiting the broad spectral coverage of the X-shooter data, we used the ratios of trans-auroral emission lines of [S II] and [O II] to estimate the electron densities, finding that most of the outflows have gas densities (log(ne cm−3) ∼ 3 − 4.8), which we speculate could be the result of compression by jet-induced shocks. Combining our estimates of the emission-line luminosities, radii, and densities, we find that the kinetic powers of the warm outflows are a relatively small fraction of the energies available from the accretion of material onto the central supermassive black hole, reflecting AGN feedback efficiencies below 1% in most cases. Overall, the warm outflows detected in our sample are strikingly similar to those found in nearby ultraluminous infrared galaxies, but more energetic and with higher feedback efficiencies on average than the general population of nearby AGN of similar bolometric luminosity; this is likely to reflect a high degree of coupling between the jets and the near-nuclear ISM in the early stages of radio source evolution.

The quasar feedback survey: discovering hidden Radio-AGN and their connection to the host galaxy ionized gas

“…Multiple studies of local and low-redshift AGNs ( z < 0.8) have shown that the level of radio emission in AGN host galaxies is strongly connected to the presence of ionized outflows, which have primarily been identified through broad and asymmetric [O III] emission lines (see e.g. Heckman et al 1981;Wilson & Heckman 1985;Veilleux 1991;Whittle 1992;Nelson & Whittle 1996;O'Dea 1998;Holt, Tadhunter & Morganti 2008;Kim et al 2013;Mullaney et al 2013;Villar Martín et al 2014;Santoro et al 2020). Across these studies, this observation holds for a wide range of AGN luminosities (i.e.…”

“…Overall, by focusing on sources at z ≈ 0.1, our survey allows for both a reasonable spatial resolution (∼1 kpc) and sensitivity, while also allowing us to build up a sample of bolometrically luminous AGNs (also see e.g. Husemann et al 2013;Karouzos, Woo & Bae 2016;Rupke, Gültekin & Veilleux 2017;Rose et al 2018;Rakshit & Woo 2018b;Balmaverde et al 2020;Santoro et al 2020). Importantly, we have selected our quasars from a well-studied parent sample (Section 2.2) and, as is usually not the case for bolometrically luminous 'radio-quiet' quasars, we will start with a detailed study of the spatially resolved radio properties.…”

Jet-driven AGN feedback on molecular gas and low star-formation efficiency in a massive local spiral galaxy with a bright X-ray halo

“…The energy injection from active galactic nuclei (AGN) into the interstellar gas of their host galaxy is now a widely accepted mechanism of galaxy evolution, which is mainly supported by the observation of fast outflows in galaxies associated with powerful AGN (e.g., Morganti et al 2005;Nesvadba et al 2006Nesvadba et al , 2008Nesvadba et al , 2017Hardcastle et al 2012;Mahony et al 2013;Nyland et al 2013;Harrison et al 2014;Woo et al 2016;Karouzos et al 2016;Fiore et al 2017;Mukherjee et al 2018;Komossa et al 2018;Menci et al 2019;Zovaro et al 2019;Santoro et al 2020). About 30% of nearby massive radio galaxies, which host considerable amounts of warm or cold molecular gas (Ocaña Flaquer et al 2010;Ogle et al 2010;Dicken et al Based on data obtained with ALMA through program 2019.1.01492.S and with IRAM through program 080-19.…”

The AGN fuelling/feedback cycle in nearby radio galaxies – IV. Molecular gas conditions and jet–ISM interaction in NGC 3100

“…In the past decade, ho we ver, jet-mode feedback has been increasingly observed to alter the distribution, kinematics, and physics of the surrounding gaseous medium also on (sub-)kpc scales (e.g. Combes et al 2013 ;Garc ía-Burillo et al 2014 ;Morganti et al 2015 ;Mahony et al 2016 ;Murthy et al 2019 ;Zovaro et al 2019 ;Santoro et al 2020 ;Venturi et al 2021 , see also Veilleux et al 2020 , for a recent re vie w on this subject). Observations find support in three-dimensional (3D) hydrodynamical simulations (e.g.…”