  One of the most important questions in cosmology is concerning the
fundamental nature of dark matter (DM). DM could consist of spinless particles
of very small mass i.e. $m \sim 10^{-22}\ \text{eV}$. This kind of ultralight
dark matter (ULDM) would form cored density profiles (called "solitons") at the
centre of galaxies. In this context, recently it has been argued that (a) there
exists a power law relation between the mass of the soliton and mass of the
surrounding halo called the Soliton-Halo (SH) relation, and, (b) the
requirement of satisfying observed galactic rotation curves as well as SH
relations is so stringent that ULDM is disfavoured from comprising $100\%$ of
the total cosmological dark matter. In this work, we revisit these constraints
for ULDM particles with non-negligible quartic self-interactions. Using a
recently obtained soliton-halo relation which takes into account the effect of
self-interactions, we present evidence which suggests that, for $m = 10^{-22}\
\text{eV}$, the requirement of satisfying both galactic rotation curves as well
as SH relations can be fulfilled with repulsive self-coupling $\lambda \sim
\mathcal{O}(10^{-90})$.
