Misc,
Fueling AGN-I: How the Global Characteristics of the Central Kiloparsec of Seyferts differ from Quiescent Galaxies
(2013)cite arxiv:1303.4399Comment: 17 pages, 22 figures. Accepted for publication in the Astrophysical Journal.
Abstract
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 ten
galaxies. We find several differences within a radius of 500 pc that are
correlated with 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 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 active galactic nucleus (AGN) is thus associated with the formation of
a dynamically cold component of gas and stars on scales of hundreds of parsecs.
