The starburst-AGN connection: the role of young stellar populations in
  fueling supermassive black holes
  Tracing the star formation history in circumnuclear regions (CNRs) is a key
step towards understanding the starburst-AGN connection. However, bright nuclei
outshining the entire host galaxy prevent the analysis of the stellar
populations of CNRs around type-I AGNs. Obscuration of the nuclei by the
central torus provides an unique opportunity to study the stellar populations
of AGN host galaxies. We assemble a sample of 10, 848 type-II AGNs with a
redshift range of $0.03\le z\le 0.08$ from the Sloan Digital Sky Survey's Data
Release 4, and measure the mean specific star formation rates (SSFRs) over the
past 100Myr in the central $\sim1-2$ kpc . We find a tight correlation between
the Eddington ratio ($\lambda$) of the central black hole (BH) and the mean
SSFR, strongly implying that supernova explosions (SNexp) play a role in the
transportation of gas to galactic centers. We outline a model for this
connection by accounting for the role of SNexp in the dynamics of CNRs. In our
model, the viscosity of turbulence excited by SNexp is enhanced, and thus
angular momentum can be efficiently transported, driving inflows towards
galactic centers. Our model explains the observed relation $\lambda \propto \rm
SSFR^{1.5-2.0}$, suggesting that AGN are triggered by SNexp in CNRs.
