X-ray scaling relations of elliptical galaxies

Abstract

We present the X-ray scaling relations of a sample of elliptical galaxies using X-ray Chandra observations. We use a single β-model to reconstruct the density gas profile and the hydrostatic equation to measure the total mass. We build X-ray scaling relations between temperature, luminosity and total mass at 5Re. Our sample in- cludes gas-poor objects that help us to extend already published LX − T , M − T and LX − M scaling relations to lower magnitudes. The derived slopes for all three relations are much steeper than those for galaxy clusters and groups, and are extreme compared to self-similar models considering gravity only. This increase of steepness from clusters to galaxies indicates that non-thermal processes (e.g. AGN feedback) have a stronger influence on the small-scale systems. Our results indicate that the hot interstellar medium of gas-poor early-type galaxies is not in the wind/outflow state as suggested by recent hydrodynamical simulations. We also discuss the possible biases of our calculations and compare our results to recent papers.