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The active galaxy MCG-C6-30-15 has a 400 pc diameter stellar kinematically distinct core, counter-rotating with respect to the main body of the galaxy. Our previous high spatial resolution (0.1 arcsec) H-band observations of this galaxy mapped the stellar kinematics and [Fe II] 1.64 μm gas dynamics though mainly restricted to the spatial region of the counter-rotating core. In this work, we probe the stellar kinematics on a larger field of view and determine the ionized and molecular gas dynamics to study the formation of the counter-rotating core and the implications for active galactic nucleus (AGN) fuelling. We present integral field spectroscopy observations with SINFONI in the H and K bands in the central 1.2 kpc and with VIMOS HR-blue in the central 4 kpc of the galaxy. Ionized gas outflows of vout ~ 100 km s.1 are traced by the [Ca VIII] 2.32 μm coronal line and extend out to at least a radius of r ~ 140 pc. The molecular gas, traced by the H2 2.12 μm emission, is also counter-rotating with respect to the main body of the galaxy, indicating that the formation of the distinct core was associated with inflow of external gas into the centre of MCG-C6-30-15. The molecular gas traces the available gas reservoir for AGN fuelling and is detected as close as r ~ 50-C100 pc. External gas accretion is able to significantly replenish the fuelling reservoir suggesting that the event which formed the counter-rotating core was also the main mechanism providing gas for AGN fuelling. [ABSTRACT FROM AUTHOR]

Galactic gas-gas collisions involving a turbulent multiphase interstellar medium (ISM) share common ISM properties: dense extraplanar gas visible in CO, large linewidths (≳50 km s-1), strong mid-infrared H2 line emission, low star formation activity, and strong radio continuum emission. Gas-gas collisions can occur in the form of ram pressure stripping caused by the rapid motion of a spiral galaxy within the intracluster medium, galaxy head-on collisions, compression of the intragroup gas and/or galaxy ISM by an intruder galaxy which flies through the galaxy group at a high velocity, or external gas accretion on an existing gas torus in a galactic center. We suggest that the common theme of all these gas-gas interactions is adiabatic compression of the ISM leading to an increase of the turbulent velocity dispersion of the gas. The turbulent gas clouds are then overpressured and star formation is quenched. Within this scenario we developed a model for turbulent clumpy gas disks where the energy to drive turbulence is supplied by external infall or the gain of potential energy by radial gas accretion within the disk. The cloud size is determined by the size of a continuous (C-type) shock propagating in dense molecular clouds with a low ionization fraction at a given velocity dispersion. We give expressions for the expected volume and area filling factors, mass, density, column density, and velocity dispersion of the clouds. The latter is based on scaling relations of intermittent turbulence whose open parameters are estimated for the circumnuclear disk in the Galactic center. The properties of the model gas clouds (∼0.1 pc, ∼100 M⊙, Δv ≳ 6 kms-1) and the external mass accretion rate necessary for the quenching of the star formation rate due to adiabatic compression (Ṁ ∼ 1-10 M⊙ yr-1) are consistent with those derived from high-resolution H2 2.12 μm line observations. Based on these findings, a scenario for the evolution of gas tori in galactic centers is proposed and the implications for star formation in the Galactic center are discussed. [ABSTRACT FROM AUTHOR]

In a matched sample of Seyfert and quiescent galaxies we simultaneously probe the stellar and molecular gas kinematics from 1 kpc down to 50 pc with the aim of identifying the dynamical processes dictating black hole accretion rates. This first paper compares the global characteristics of a sample of 10 galaxies. We find several differences within a radius of 500 pc that are correlated with active galactic nucleus (AGN) activity. The Seyferts have (1) a more centrally concentrated nuclear stellar surface brightness with lower stellar luminosities beyond a radius of 100 pc, (2) a lower stellar velocity dispersion within a radius of 200 pc, (3) elevated H2 1-0 S(1) luminosity out to a radius of at least 250 pc, and (4) more centrally concentrated H2 surface brightness profiles. These observed differences can be interpreted as evidence for Seyfert galaxies having a dynamically cold (in comparison to the bulge) nuclear structure composed of a significant gas reservoir and a relatively young stellar population. This structure is undetected (and possibly does not exist) in quiescent galaxies. The presence of such a nuclear structure in Seyfert galaxies provides evidence for inflow of the surrounding interstellar medium since the nuclear stellar population requires a supply of gas from which to form. The fueling of a Seyfert AGN is thus associated with the formation of a dynamically cold component of gas and stars on scales of hundreds of parsecs. [ABSTRACT FROM AUTHOR]

As part of an extensive study of the physical properties of active galactic nuclei (AGNs) we report high spatial resolution near-IR integral-field spectroscopy of the narrow-line region (NLR) and coronal-line region (CLR) of seven Seyfert galaxies. These measurements elucidate for the first time the two-dimensional spatial distribution and kinematics of the recombination line Bry and high-ionization lines [Si VI], [Al IX], and [Ca VIII] on scales <300 pc from the AGN. The observations reveal kinematic signatures of rotation and outflow in the NLR and CLR. The spatially resolved kinematics can be modeled as a combination of an outflow bicone and a rotating disk coincident with the molecular gas. High-excitation emission is seen in both components, suggesting it is leaking out of a clumpy torus. While NGC 1068 (Seyfert 2) is viewed nearly edge-on, intermediate-type Seyferts are viewed at intermediate angles, consistent with unified schemes. A correlation between the outflow velocity and the molecular gas mass in r < 30 pc indicates that the accumulation of gas around the AGN increases the collimation and velocity of the outflow. The outflow rate is 2-3 orders of magnitude greater than the accretion rate, implying that the outflow is mass loaded by the surrounding interstellar medium (ISM). In half of the observed AGNs, the kinetic power of the outflow is of the order of the power required by two-stage feedback models to be thermally coupled to the ISM and to match the MBH-σ* relation. In these objects, the radio jet is clearly interacting with the ISM, indicative of a link between jet power and outflow power. [ABSTRACT FROM AUTHOR]