Ultralight dark matter in disk galaxies

Abstract

Analytic arguments and numerical simulations show that bosonic ultralight dark matter (ULDM) would form cored density distributions (``solitons'') at the center of galaxies. ULDM solitons offer a promising way to exclude or detect ULDM by looking for a distinctive feature in the central region of galactic rotation curves. Baryonic contributions to the gravitational potential pose an obstacle to such analyses, being (i) dynamically important in the inner galaxy and (ii) highly nonspherical in rotation-supported galaxies, resulting in nonspherical solitons. We present an algorithm for finding the ground-state soliton solution in the presence of stationary nonspherical background baryonic mass distribution. We quantify the impact of baryons on the predicted ULDM soliton in the Milky Way and in low-surface-brightness galaxies from the SPARC database.