Model-independent constraints on ultra-light dark matter from the SPARC data

Abstract: Ultra-light dark matter (ULDM) is currently one of the most popular classes of cosmological dark matter. The most important advantage is that ULDM with mass $m \sim 10^{-22}$ eV can account for the small-scale problems encountered in the standard cold dark matter (CDM) model like the core-cusp problem, missing satellite problem and the too-big-to-fail problem in galaxies. In this article, we formulate a new simple model-independent analysis using the SPARC data to constrain the range of ULDM mass. In particular, the most stringent constraint comes from the data of a galaxy ESO563-G021, which can conservatively exclude a ULDM mass range $m=(0.14-3.11)\times 10^{-22}$ eV. This model-independent excluded range is consistent with many bounds obtained by recent studies and it suggests that the ULDM proposal may not be able to alleviate the small-scale problems.