paper

A Catalogue and Analysis of X-ray luminosities of Early-type galaxies

arXiv:astro-ph/0108181 · doi:10.1046/j.1365-8711.2001.04890.x

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 modeled by a single powerlaw fit. We also derive estimates of the contribution to galaxy X-ray luminosities from discrete sources and conclude that they provide L_discrete/L_B = 29.5 erg/s/L_solar. We compare this result to luminosities from our catalogue. Lastly, we examine the influence of environment on galaxy X-ray luminosity and on the form of the L_X:L_B 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.

33 pages, 16 postscript figures, accepted for publication in MNRAS

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