Motion in time-periodic backgrounds with applications to ultralight dark matter haloes at galactic centers

Understand

We consider motion in spherically symmetric but time-dependent backgrounds.

• This problem is of interest, for example, in the context of ultralight dark matter, where galactic haloes produce a time-dependent and periodic gravitational potential.
• We study the properties of motion of stars in such spacetimes, for different field strengths and frequency, and including dissipative effects.
• We show that orbital resonances may occur and that spectroscopic emission lines from stars in these geometries exhibit characteristic, periodic modulation patterns.