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Recent observations of microlensing events in the Large Magellanic Cloud suggest that a sizeable fraction of the galactic halo is in form of MACHOs with mass less than abou 0.1 M_{odot}. Here we argue that molecular clouds (mainly H_2) located in the galactic halo can contribute substantially to its total mass. We outline a scenario in which dark clusters of MACHOs and molecular clouds naturally form in the halo at large galactocentric distances. Possible ways of detecting MACHOs via infrared emission and molecular clouds via the induced gamma-ray flux are discussed. Molecular clouds located in the M31 dark halo could be discovered through cosmic background radiation (CBR) anisotropies or emission lines in the microwave band.
Oscillations in the baryon-photon fluid prior to recombination imprint different signatures on the power spectrum and correlation function of matter fluctuations. The measurement of these features using galaxy surveys has been proposed as means to de
We investigated a hydrostatic equilibrium model of the Milky Way following Parker (1966), to constrain the large scale properties of the interstellar medium. In our approach we found an excellent agreement between our simple hydrostatic equilibrium m
We have used RR Lyrae and Blue HB stars as tracers of the old Galactic halo, in order to study the halo structure and the galactic rotation as a function of height above the plane. Our sample includes 40 RR Lyrae and 80 BHB stars that are about 2 to
We investigate the convective stability of two popular types of model of the gas distribution in the hot Galactic halo. We first consider models in which the halo density and temperature decrease exponentially with height above the disk. These halo m
We explore differences in Galactic halo kinematic properties derived from two commonly employed Galactic potentials: the St$ddot{a}$ckel potential and the default Milky Way-like potential used in the Galpy package (MWPotential2014), making use of sta