The making and testing of spin-2 ULDM galaxies

Ultra-light dark matter (ULDM) is a compelling and phenomenologically rich candidate for the cosmological dark matter. ULDM is typically considered to be a (pseudo)scalar or a vector field, but even more interesting and unique physics can be realised for spin-2 tensor fields.

In this talk I will review how spin-2 dark matter arises from the only known consistent modification of gravity to include multiple spin-2 fields, and discuss (a) how the ULDM spin changes the properties of idealised haloes obtained through isolated soliton mergers, (b) how to detect spin-2 ULDM using pulsar-timing data, in particular how to detect perturbations in binary systems with machine-learning techniques, and (c) how to detect spin-2 ULDM with gravitational wave interferometers, with an emphasis on existing LIGO/Virgo data.