The Lx-σ relation for galaxies and clusters of galaxies

We demonstrate that individual elliptical galaxies and clusters of galaxies form a continuous X-ray luminosity-velocity dispersion (L-x-sigma) relation. Our samples of 280 clusters and 57 galaxies have L-x proportional to sigma (4.4) and L-x proportional to sigma (10), respectively. This unified relation spans 8 orders of magnitude in and is fully consistent with the observed L - L and theoretical luminosity-temperature scaling laws. Our results support the notion that galaxies and clusters of galaxies are the luminous tracers of similar dark matter halos.