The AGN Ionization Cones of NGC 5728 : II - Kinematics

Abstract

We explore the gas morphology and excitation mechanisms of the ionization cones of the Type II Seyfert galaxy NGC~5728. Kinematics derived from near-IR and optical data from the SINFONI and MUSE IFUs on the VLT reveal AGN-driven outflows powered by a super-massive black hole (SMBH) of mass 3.4$\times$10$^2$ M$_\odot$, bolometric luminosity of 1.46$\times$10$^{44}$ erg/s, Eddington ratio 3.3$\times$10$^{-2}$ and an accretion rate of 2.7$\times$10$^2$ M$_\odot$/yr. The symmetric bicone outflows show rapid acceleration to $\pm$250 km/s at $\sim$250 pc, then decelerating to $\sim$130 km/s at 500 pc from the AGN, with an estimated mass outflow rate of 38 M$_\odot$/yr, the mass ratio of outflows to accretion is 1415. The kinetic power is 1.5$\times$10$^{42}$ erg/s, 1$\%$ of the bolometric luminosity. Over the AGN active lifetime of $\sim$10$^7$ years, 1.6$\times$10$^8$ M$_\odot$ of gas can become gravitationally unbound from the galaxy, a large proportion of the gas mass available for star formation in the nuclear region. The bicone internal opening angle (50\deg.2) and the inclination to the LOS (47\deg.6) were determined from [Fe II] line profiles, the outflow axis is nearly parallel to the plane of the galaxy. This geometry supports the Unified Model of AGN, as these angles preclude seeing the accretion disk, which is obscured by the dusty torus.