Synthetic observations of simulated active galactic nucleus jets: X-ray cavities

Abstract

Observations of X-ray cavities formed by powerful jets from active galactic nuclei (AGNs) in galaxy cluster cores are widely used to estimate the energy output of the AGNs. Using methods commonly applied to observations of clusters, we conduct synthetic X-ray observations of 3D MHD simulated jet-intracluster medium interactions to test the reliability of measuring X-ray cavity power. These measurements are derived from empirical estimates of the enthalpy content of the cavities and their implicit ages. We explore how such physical factors as jet intermittency and observational conditions such as orientation of the jets with respect to the line of sight impact the reliability of observational measurements of cavity enthalpy and age. An estimate of the errors in these quantities can be made by directly comparing "observationally" derived values with "actual" values from the simulations. In our tests, cavity enthalpy derived from observations was typically within a factor of two of the simulation values. Cavity age and, therefore, cavity power are sensitive to the accuracy of the estimated inclination angle of the jets. Cavity age and power estimates within a factor of two of the actual values are possible given an accurate inclination angle. © 2011. The American Astronomical Society. All rights reserved.