Supermassive dark-matter Q-balls in galactic centers?
  Though widely accepted, it is not proven that supermassive compact objects
(SMCOs) residing in galactic centers are black holes. In particular, the Milky
Way's SMCO can be a giant nontopological soliton, Q-ball, made of a scalar
field: this fits perfectly all observational data. Similar but tiny Q-balls
produced in the early Universe may constitute, partly or fully, the dark
matter. This picture explains in a natural way, why our SMCO has very low
accretion rate and why the observed angular size of the corresponding radio
source is much smaller than expected. Interactions between dark-matter Q-balls
may explain how SMCOs were seeded in galaxies and resolve well-known problems
of standard (non-interacting) dark matter.
