It is inferred from the symmetrical and luminous X-ray emission of fossil groups that they are mature, relaxed galaxy systems. Cosmological simulations and observations focusing on their dark halo and inter-galactic medium properties confirm their early formation. Recent photometric observations suggest that, unlike the majority of non-fossil brightest group galaxies (BGGs), the central early-t...

We compare the statistical properties of J=1→0 CO spectra observed in the Perseus Molecular Cloud with synthetic J=1→0 CO spectra, computed solving the non–LTE radiative transfer problem for a model cloud obtained as solutions of the three dimensional magneto–hydrodynamic (MHD) equations. The model cloud is a randomly forced super–Alfvénic and highly super–sonic turbulent isothermal flow. The p...