Tidal streams from axion miniclusters and direct axion searches

Understand

In some axion dark matter models a dominant fraction of axions resides in dense small-scale substructures, axion miniclusters.

• A fraction of these substructures is disrupted and forms tidal streams where the axion density may still be an order of magnitude larger than the average.
• We discuss implications of these streams for the direct axion searches.
• We estimate the fraction of disrupted miniclusters and the parameters of the resulting streams, and find that stream-crossing events would occur at a rate of about $1/(20 {\rm yr})$ for 2-3 days, during which the signal in axion detectors would be amplified by a factor $\sim 10$.