Authors: Alister W. Graham
Abstract: This work advances the (galaxy morphology)-dependent (black hole mass, Mbh)-(spheroid/galaxy stellar mass, M*) scaling relations by introducing `dust bins' for lenticular (S0) galaxies. Doing so has led to the discovery of Mbh–M*,spheroid and Mbh–M*,galaxy relations for dusty S0 galaxies — built by major wet mergers and comprising half the S0 sample — offset from the distribution of dust-poor S0 galaxies. The situation is reminiscent of how major dry mergers of massive S0 galaxies have created an offset population of ellicular and elliptical galaxies. For a given Mbh, the dust-rich S0 galaxies have 3–4 times higher M*,sph than the dust-poor S0 galaxies, and the steep distributions of both populations in the Mbh–M*,spheroid diagram bracket the Mbh∝M*,spheroid2.27±0.48 relation defined by the spiral galaxies, themselves renovated through minor mergers. The new relations offer refined means to estimate Mbh in other galaxies and should aid with: (i) constructing (galaxy morphology)-dependent black hole mass functions; (ii) estimating the masses of black holes associated with tidal disruption events; (iii) better quantifying evolution in the scaling relations via improved comparisons with high-z data by alleviating the pickle of apples versus oranges; (iv) mergers and long-wavelength gravitational wave science; (v) simulations of galaxy/black hole coevolution and semi-analytic works involving galaxy speciation; plus (vi) facilitating improved extrapolations into the intermediate-mass black hole landscape. The role of the galaxy's environment is also discussed, and many potential projects that can further explore the morphological divisions are mentioned.