Flattened galactic haloes and baryonic dark matter

We discuss the tight interconnection between microlensing optical depths, flattening of dark haloes and low-to-intermediate redshift baryonic census. By analysing plots of the microlensing optical depth as a function of Galactic coordinates for different values of axis ratio q of the Galactic MACHO halo, we have shown that observations are best described by a flattened halo with q≃0.6. There is no dynamical obstacle for such a choice of global halo shape. Both extremely flattened q≃0.2 and spherical q≃1 haloes have several difficulties, although not of equal severity. Consequences of such flattening for the cosmological density fraction contained in MACHOs are considered, and comparison with mass in low- and intermediate-redshift Lyα forest and other plausible reservoirs of gas is discussed in context of a unified description of the evolution of baryonic content of the Universe.