The X-ray luminosity-velocity dispersion relation in the REFLEX cluster survey

We present an estimate of the bolometric X-ray luminosity-velocity dispersion (L-x-sigma(v)) relation measured from a new, large and homogeneous sample of 171 low-redshift, X-ray selected galaxy clusters. The linear fitting of log(L-x)-log(sigma(v)) gives L-x = 10(32.72+/-0.08)sigma(v)(4.1+/-0.3) erg s(-1) h(50)(-2). Furthermore, a study of 54 clusters, for which the X-ray temperature of the intracluster medium T is available, allows us to explore two other scaling relations, L-x-T and sigma(v)-T. From this sample we obtain L-x proportional to T3.1+/-0.2 and sigma(v) proportional to T1.00+/-0.6, which are fully consistent with the above result for L-x-sigma(v). The slopes of L-x-T and sigma(v)-T are incompatible with the values predicted by selfsimilarity (L-x proportional to T-2 proportional to sigma(v)(4)), thus suggesting the presence of non-gravitational energy sources heating up the intracluster medium, in addition to the gravitational collapse, in the early stages of cluster formation. On the other hand, the result on log(L-x)-log(sigma(v)) supports the self-similar model.