Date Presented:

2009/09/1

Abstract:

We present results on the X-ray source populations of nearby spiral and star-forming galaxies. The sample of galaxies includes the nearby spiral galaxy M81 and star-forming galaxies with stellar populations in the 10-100Myr range. We use HST data in order to classify the X-ray sources to HMXBs, LMXBs and globular clusters, and identify any SNRs or background AGNs. We discuss the spectral and temporal characteristics of the different sub-populations in these galaxies, and their implications for the sources' nature. We present the X-ray luminosity functions (XLF) of the discrete sources from the individual as well as the co-added observations and we discuss the dependence of the XLF on the age of the stellar populations. In the case of M81 we find a population of sources in the 10^{36}-10^{37} erg s^{-1} luminosity range with early-type counterparts, while the HMXBs in the star-forming galaxies have generally higher luminosities. We also present results from Chandra observations of the SMC which extend the XLFs down to luminosities of 10^{32} erg s^{-1} and show evidence for the onset of the propeller effect at low luminosities.

Website