ULDM self-interactions, tidal effects and tunnelling out of satellite galaxies

Understand

It is well-known that Dark Matter (DM) inside a satellite galaxy orbiting a host halo experiences a tidal potential.

• If DM is ultra-light, given its wave-like nature, one expects it to tunnel out of the satellite - if this happens sufficiently quickly, then the satellite will not survive over cosmological timescales, severely constraining this dark matter model.
• In this paper, we study the effects of the inevitable quartic self-interaction of scalar Ultra-Light Dark Matter (ULDM) on the lifetimes of satellite galaxies by looking for quasi-stationary solutions with outgoing wave boundary conditions.
• For a satellite with some known core mass and orbital period, we find that, attractive (repulsive) self-interactions decrease (increase) the rate of tunnelling of DM out of it.