Mass-temperature relation of galaxy clusters: A theoretical study

Combining conservation of energy throughout the nearly spherical collapse of galaxy clusters with the virial theorem, we derive the mass-temperature relation for X-ray clusters of galaxies, T = CM2/3. The normalization factor C and the scatter of the relation are determined from first principles, with the additional assumption of an initial Gaussian random field. We are also able to reproduce the recently observed break in the M-T relation at T similar to 3 keV, based on the scatter in the underlying density field for a low-density LambdaCDM cosmology. Finally, by combining observational data of high-redshift clusters with our theoretical formalism, we find a semiempirical temperature-mass relation that is expected to hold at redshifts up to unity with less than 20% error.