Dynamics of Axion Clumps in the Milky Way halo to study Dark Matter

Abstract

In a wide variety of axion models, a relevant fraction of all Dark Matter (DM) is expected to bound in dense small-scale substructures, called axion miniclusters. Despite they enhance the local DM density, the crossing of miniclusters through Earth are rare events occurring once in 105 years making direct detection inefficient. Although dense, a small fraction of these structures become unbound by tidal interaction with astronomical objects, as shown mainly with stars. The perspectives of detection will depend on which fraction of axion minicluster gets disrupted and therefore, tidal interactions are reviewed in detail in this paper. As a result of the destruction, tidal axion streams are expected to form along the minicluster’s previous direction in a coherentand large shape. Stream crossings are more probable events so it has been analysed if density may still be larger than the local DM density and therefore, be a real chance in direct detection systems such as haloscopes