The Black Hole Mass Function Derived from Local Spiral Galaxies

We present our determination of the nuclear supermassive black hole 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 (delta < 0 degrees) Hemisphere. The sample is defined by a limiting luminosity (redshift-independent) distance, D-L = 25.400 Mpc (z = 0.0057168) and a limiting absolute B-band magnitude, m(B) = 19.1223. 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 logarithmic spiral arm pitch angle and the mass of the central supermassive black hole in a host galaxy in order to estimate the mass of the 128 respective supermassive black holes in this volume-limited sample. This result effectively gives us the distributiori of mass for supermassive black holes residing in spiral galaxies over a lookback time, t(L) <= 82.140 h(677)(-1) Myr and contained within a comoving volume, V-C = 3.3739 x 10(4) h(67.77)(-3) Mpc(3). We estimate the density of supermassive black holes residing in spiral galaxies in the Local Universe is rho = 5.54(-2.73)(+6.55) x 10(4) h(67.77)(3) M-circle dot Mpc(-3). Thus, our derived cosmological supermassive black hole mass density for spiral galaxies is Omega(BH) = 4.35(-2.15)(+5.14) x 10(-7) h(67.77). Assuming black holes grow via baryonic accretion, we predict that 0.0020(-0.0010)(+0.0023) h(67.77)(3) % of the universal baryonic inventory (Omega(BH)/omega(b)) is confined within nuclear supermassive black holes at the center of spiral galaxies.