Properties of Ultralight Bosons from Spins of Heavy Quasars via
  Superradiance
  The mass and the spin of accreting and jetted black holes, at the center of
Active Galactic Nuclei (AGNs), can be probed by analyzing their electromagnetic
spectra. For this purpose, we use the Spin-Modified Fundamental Plane of black
hole activity, which non-linearly connects the following four variables (in the
source frame): radio luminosity, X-ray or optical luminosity (via the [OIII]
emission line), black hole mass and spin. Taking into account the uncertainties
in luminosity measurements, conversion factors, relativistic beaming and
physical properties of the AGN system, we derive lower bounds on the spins of a
group of heavy, jetted AGNs. Using these results, we study the direct
implications on the mass spectrum of the ultra-light particles of scalar
(axion-like), vector (dark photon) and tensor types (additional spin-2
particles). We close unexplored gap in the parameter space
$10^{-20}-10^{-19}$eV. We obtain upper bounds on the axion decay constant
(equivalently lower bounds on the self-interaction strength) considering
self-interactions could prevent the axion particles entering the instability,
and be the reason for non-observation of superradiance. Assuming axion is
described by mass and decay constant, we obtain upper limits on what fraction
of dark matter can be formed by ultra-light particles and find that single
spieces axion-like light particle can constitute at most $10\%$ of the dark
matter in the mass range: $ 10^{-21} < \mu \, (\mathrm{eV}) < 10^{-17}$.
