The Black Hole Mass Function Derived from Local Spiral Galaxies
  We present our determination of the nuclear supermassive black hole (SMBH)
mass function for spiral galaxies in the Local Universe, established from a
volume-limited sample consisting of a statistically complete collection of the
brightest spiral galaxies in the Southern Hemisphere. Our SMBH mass function
agrees well at the high-mass end with previous values given in the literature.
At the low-mass end, inconsistencies exist in previous works that still need to
be resolved, but our work is more in line with expectations based on modeling
of SMBH evolution. This low-mass end of the spectrum is critical to our
understanding of the mass function and evolution of SMBHs since the epoch of
maximum quasar activity. A luminosity distance $\leq$ 25.4 $Mpc$ and an
absolute B-band magnitude $\leq$ -19.12 define the sample. These limits define
a sample of 140 spiral galaxies, with 128 measurable pitch angles to establish
the pitch angle distribution for this sample. This pitch angle distribution
function may be useful in the study of the morphology of late-type galaxies. We
then use an established relationship between the pitch angle and the mass of
the central SMBH in a host galaxy in order to estimate the mass of the 128
respective SMBHs in this sample. This result effectively gives us the
distribution of mass for SMBHs residing in spiral galaxies over a lookback time
$\leq$ 82.1 $h_{67.77}^{-1}$ $Myr$ and contained within a comoving volume of
3.37 $\times$ $10^4$ $h_{67.77}^{-3}$ $Mpc^3$. We estimate the density of SMBHs
residing in spiral galaxies in the Local Universe is $5.54_{-2.73}^{+6.55}$
$\times$ $10^4$ $h_{67.77}^3$ $M_{\odot}$ $Mpc^{-3}$. Thus, our derived
cosmological SMBH mass density for spiral galaxies is $\Omega_{BH} =
4.35_{-2.15}^{+5.14}$ $\times$ $10^{-7}$ $h_{67.77}$.
