Gravitational collapse and non-self-similarity in the L-T relation

摘要

We derive the luminosity-temperature relation for clusters of galaxies by means of a modification of the self-similar model to take account of angular momentum acquisition by protostructures and of an external pressure term in the virial theorem. We show that the above effect leads, in X-rays, to a luminosity-temperature relation that scales as L proportional to T-5, at scale of groups, flattening to L proportional to T-3 for rich clusters and converging to L proportional to T-2 at higher temperatures. The fundamental result of the model is that gravitational collapse, which takes account of angular momentum acquisition, can explain the nonself-similarity in the L-T relation, in disagreement with the largely accepted assumption that heating/cooling processes and similar are fundamental in the originating the non-self-similar behavior (shaping) of the L-T relation.