Gravitational-wave observations of extreme mass ratio inspirals (EMRIs) hold incredible potential to probe gravity, astrophysical and exotic environments. One of the main effects of astrophysical environments — in particular active galactic nuclei — is the torque exerted by their gaseous disk, which forces EMRIs to “migrate” (mostly) inward like planets.
Primordial black holes (PBHs) might form in the early universe and could comprise a significant fraction of the dark matter. If they are generated due to enhanced scalar perturbations at small scales, their formation is inevitably accompanied by the emission of gravitational waves (GWs) that could be seen by current and future GW experiments.
Ultralight dark matter is an exciting alternative to the standard cold dark matter paradigm, reproducing its large scale predictions, while solving most of its potential tension with small scale observations (like the "cusp-core" and "missing satellites" problems).
Due to their high compactness and strong gravitational field, neutron stars offer us natural astrophysical laboratories to test extrem
I will discuss new degrees of freedom of gravity as motivated by string theory. Although they are expected to be generically quantum mechanical, classes of such states are coherent enough to admit classical descriptions in Einstein gravity. I will explain how to describe them as novel ultra-compact geometries without horizon or singularity.
