Timing the Beast: A Spectro-Timing Approach to Understanding X-ray Binaries

Abstract

Neither spectral nor timing studies alone allow us to disentangle the complex interplay of accretion and ejection processes. In this talk, I will show how combining both methods allows for an (almost) model-independent description of X-ray binary behavior across different accretion and ejection regimes and gives clues as to the contributions of accretion disk, disk winds, jets and Comptonization corona to the X-ray spectrum. A better grasp of the long-term evolution is also crucial for the interpretation of individual high resolution observations, e.g., by Chandra.As an example, we use over 12 years of RXTE monitoring of the black hole Cygnus X-1 to build up a template of spectro-timing behavior which enables an easy comparison among accreting sources acting on different mass and time scales. In particular, we can avoid misidentification of power spectral components in other black hole binaries that are less well sampled and therefore do not allow tracking of power spectral components across spectral states. Important is also the comparison with AGN, where many of the relevant variability time scales that shape the interaction of the supermassive black hole with its surroundings are not accessible during an astronomer_s14s lifetime.