The X-ray Halo Scaling Relations of Supermassive Black Holes
  We carry out a comprehensive Bayesian correlation analysis between hot halos
and direct masses of supermassive black holes (SMBHs), by retrieving the X-ray
plasma properties (temperature, luminosity, density, pressure, masses) over
galactic to cluster scales for 85 diverse systems. We find new key scalings,
with the tightest relation being the $M_\bullet-T_{\rm x}$, followed by
$M_\bullet-L_{\rm x}$. The tighter scatter (down to 0.2 dex) and stronger
correlation coefficient of all the X-ray halo scalings compared with the
optical counterparts (as the $M_\bullet-\sigma_{\rm e}$) suggest that plasma
halos play a more central role than stars in tracing and growing SMBHs
(especially those that are ultramassive). Moreover, $M_\bullet$ correlates
better with the gas mass than dark matter mass. We show the important role of
the environment, morphology, and relic galaxies/coronae, as well as the main
departures from virialization/self-similarity via the optical/X-ray fundamental
planes. We test the three major channels for SMBH growth: hot/Bondi-like models
have inconsistent anti-correlation with X-ray halos and too low feeding;
cosmological simulations find SMBH mergers as sub-dominant over most of the
cosmic time and too rare to induce a central-limit-theorem effect; the scalings
are consistent with chaotic cold accretion (CCA), the rain of matter condensing
out of the turbulent X-ray halos that sustains a long-term self-regulated
feedback loop. The new correlations are major observational constraints for
models of SMBH feeding/feedback in galaxies, groups, and clusters (e.g., to
test cosmological hydrodynamical simulations), and enable the study of SMBHs
not only through X-rays, but also via the Sunyaev-Zel'dovich effect (Compton
parameter), lensing (total masses), and cosmology (gas fractions).
