We study the impact of an intracluster magnetic field on the main structural properties of clusters and groups of galaxies : the radial density and entropy profiles , the entropy – temperature relation and the X-ray luminosity – temperature relation for groups and clusters of galaxies .
To this aim , we develop a description of the intra-cluster gas based on the Hydrostatic Equilibrium condition and on the Magnetic Virial Theorem in the presence of a radial distribution of the magnetic field B ( r ) = B _ { * } ( \rho _ { g } ( r ) ) ^ { \alpha } , with \alpha \approx 0.9 , as the one indicated by observations and numerical simulation .
Our analysis shows that such a description is able to provide , at once , a possible explanation of three problematic aspects of the cluster structure : i ) the flattening of the entropy profile in the cluster center ii ) the flatness of the S - T relation iii ) the increasing steepening of the L _ { X } - T relation from the cluster scale towards the group scales .
The available entropy and X-ray luminosity data indicate that an increase of the magnetic field B _ { * } \sim T ^ { 0.5 \pm 0.1 } is required to reproduce at the same time both the S - T and the L _ { X } - T relations .
It follows that a consistent description of the magnetized ICM can provide a simple explanation of several ( or of all ) of these still open problems , and thus weakens the need for the inclusion of other non-gravitational effects which have been proposed so far for the explanation of some of these features .
This ( initial , but not conclusive ) analysis can be regarded as a starting point for a more refined analytical exploration of the physics of the magnetized intra-cluster medium , and it provides testable predictions that can be proven or disproven with the next coming sensitive observations of groups and clusters in the X-ray band and in the radio frequency band .