An Unprecedented View of a Galaxy's Dynamic X-ray Source Population

Abstract

In May/June 2005, Chandra observed M81 fifteen times, roughly once every three days, as part of our proposal to explore the days to weeks timescale of variability for extragalactic point sources. Each observation reached a sensitivity of $5\,{\times}\,10^{36}$ erg/s. Because these observations probe the timescale on which X-ray binaries typically evolve, we can now compare extragalactic sources to Galactic X-ray binaries on a more equal level than has been possible in the past. In addition, we can measure and quantify any possible time variability of M81's X-ray luminosity function and investigate alternative methods to characterize a galaxy's dynamic X-ray source population. We present here preliminary results of the observations.