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