A catalogue and analysis of X-ray luminosities of early-type galaxies

By E. O’Sullivan, D. Forbes, T. J. P. U. O. Birmingham, S. University. 2001

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ABSTRA C T We present a catalogue of X-ray luminosities for 401 early-type galaxies, of which 136 are based on newly analysed ROSAT PSPC pointed observations. The remaining luminosities are taken from the literature and converted to a common energy band, spectral model and distance scale. Using this sample we fit the LX : LB relation for early-type galaxies and find a best-fit slope for the catalogue of ,2.2. We demonstrate the influence of group-dominant galaxies on the fit and present evidence that the relation is not well modelled by a single power-law fit. We also derive estimates of the contribution to galaxy X-ray luminosities from discrete-sources and conclude that they provide Ldscr /L B . 29:5 erg s 21 L 21 B( . We compare this result with luminosities from our catalogue. Lastly, we examine the influence of environment on galaxy X-ray luminosity and on the form of the LX : LB relation. We conclude that although environment undoubtedly affects the X-ray properties of individual galaxies, particularly those in the centres of groups and clusters, it does not change the nature of whole

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/59de8a4fc23afe768cfea06279078d049762af3b