A catalogue and analysis of X-ray luminosities of early-type galaxies |
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| Authors: | Ewan O'Sullivan Duncan A Forbes Trevor J Ponman |
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| Institution: | 1School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT;2Astrophysics &Supercomputing, Swinburne University, Hawthorn VIC 3122, Australia |
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| Abstract: | 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 L X : L B 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  . 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  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 populations. |
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| Keywords: | catalogues surveys galaxies: elliptical and lenticular cD X-rays: galaxies |
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