Supermassive primordial black holes from inflation - Aurora Ireland (U. Chicago)

Abstract: Much remains to be understood about the origin and evolution of our universe's largest supermassive black holes (SMBHs). In this talk, I motivate the possibility that some fraction of these SMBHs may be primordial in origin, having formed from the direct collapse of density perturbations seeded by inflation. Such a scenario is naively in conflict with constraints from CMB spectral distortions but can be made viable for a distribution of curvature perturbations which is sufficiently non-Gaussian. I present a concrete model of multi-field inflation capable of yielding such dramatic non-Gaussianities and calculate the maximal abundance of SMBHs, finding it to be consistent with the population observed at high-redshift. This result has a number of interesting implications and is especially timely in light of recent evidence from the NANOGrav collaboration and other pulsar timing arrays for a stochastic gravitational wave background consistent with SMBH mergers.