Talks

A recently discovered class of active galactic nuclei, TeV luminous blazars, constitute a small fraction of the power output of black holes. Nevertheless, there are suggestions that unlike the UV and X-ray luminosity of quasars, the very-high energy gamma-ray emission from the TeV blazars can be thermalized on cosmological scales with order unity efficiency, resulting in a potentially dramatic heating of the low-density intergalactic medium. The way in which this occurs, however, imparts a variety of peculiar properties to this novel heating source, resulting in a number of robust cosmological consequences. I will discuss the process by which TeV blazars heat the Universe, the strange properties that this heating has, and the variety of signatures that it has left behind, many of which have already been observed!

Most predictions for binary compact object formation are normalized to the present-day Milky Way population. In this talk, I suggest the merger rate of black hole binaries could be exceptionally sensitive to the ill-constrained fraction of low-metallicity star formation that ever occurred on our past light cone. I discuss whether and how observations might distinguish binary evolution uncertainties from this strong trend, both in the near future with well-identified electromagnetic counterparts and in the more distant future via third-generation gravitational wave detectors.