Parametric models of the periodogram
  The maximum likelihood estimator is used to determine fit parameters for various parametric models of the Fourier periodogram followed by the selection of the best fit model amongst competing models using the Akaike information criteria. This analysis, when applied to light curves of active galactic nuclei can be used to infer the presence of quasi-periodicity and break or knee frequencies. The extracted information can be used to place constraints on the mass, spin and other properties of the putative central black hole and the region surrounding it through theoretical models involving disk and jet physics. 
P. Mohan (1), A. Mangalam (1), S. Chattopadhyay (2) ((1) Indian   Institute of Astrophysics, Bangalore, INDIA (2) Bengal Eng...
astro-ph.GA astro-ph.HE