Feedback by AGN Jets and Wide-angle Winds on a Galactic Scale

Abstract

To investigate the differences in mechanical feedback from radio-loud and radio-quiet Active Galactic Nuclei (AGN) on the host galaxy, we perform 3D AMR hydrodynamic simulations of wide angle, radioquiet winds with different inclinations on a single, massive, gas-rich disk galaxy at a redshift of 2-3. We compare our results to hydrodynamic simulations of the same galaxy but with a jet. The jet has an inclination of 0• (perpendicular to the galactic plane), and the winds have inclinations of 0 • , 45• , and 90• . We analyze the impact on the host's gas, star formation, and circum-galactic medium. We find that jet feedback is energy-driven and wind feedback is momentum-driven. In all the simulations, the jet or wind creates a cavity mostly devoid of dense gas in the nuclear region where star formation is then quenched, but we find strong positive feedback in all the simulations at radii greater than 3 kpc. All four simulations have similar SFRs and stellar velocities with large radial and vertical components. However, the wind at an inclination of 90• creates the highest density regions through ram pressure and generates the highest rates of star formation due to its ongoing strong interaction with the dense gas of the galactic plane. With increased wind inclination, we find greater asymmetry in gas distribution and resulting star formation. Our model generates an expanding ring of triggered star formation with typical velocity of order 1/3 of the circular velocity, superimposed on the older stellar population. This should result in a potentially detectable blue asymmetry in stellar absorption features at kpc scales.

Relativistic jet feedback – III. Feedback on gas discs

“…Similar results have also been explored recently in other simulations such as those (Dugan et al 2017;Cielo et al 2017). Jets inclined to the disk may in fact be more common, as the the orientation of the jet with respect to the large scale disk may not be related, and in fact suggested to be random in Gallimore et al (2006); Combes (2017).…”

“…eq. 9, as well as in Gaibler et al 2012;Bieri et al 2016;Dugan et al 2017). In our simulations we find that turbulence is strongly enhanced (∼ 400 − 600 km s −1 ) to several times the initial values.…”

“…There is also evidence of enhanced star formation rate in galaxies hosting an AGN (Zinn et al 2013;Bernhard et al 2016). Several other theoretical works have also explored the possibility of AGN-induced starformation in galaxies, such as Nayakshin & Zubovas (2012), Wagner & Bicknell (2011, Dugan et al (2017) etc., where compression of gas by the AGN driven outflow can trigger star formation, similar to what we find.…”

“…The initial star formation rates at the start of different simulations, discussed later in this section, is presented in Table 4. The above definition of star formation rate used in this work (and others such as Gaibler et al 2012;Bieri et al 2015;Dugan et al 2017;Bieri et al 2016) does not depend on the temperature of the gas. An accurate estimate of star formation, must however, account for local Jeans length, ensure a converging flow and that the gravitational potential energy is higher than the local turbulent kinetic energy (Federrath et al 2010b).…”

“…SFR is an efficiency factor that defines the fraction of gas within a volume that is converted to stars. A similar definition of star formation rate has been widely used to estimate the star formation rate in computational simulations of galaxy evolution (Springel & Hernquist 2003;Dubois & Teyssier 2008) and also in recent studies of positive feedback (such as Gaibler et al 2012;Bieri et al 2015;Dugan et al 2017;Bieri et al 2016).…”