Probing Small-Scale Power Spectra with Pulsar Timing Arrays

Understand

Models of Dark Matter (DM) can leave unique imprints on the Universe's small scale structure by boosting density perturbations on small scales.

• We study the capability of Pulsar Timing Arrays to search for, and constrain, subhalos from such models.
• The models of DM we consider are ordinary adiabatic perturbations in $\Lambda$CDM, QCD axion miniclusters, models with early matter domination, and vector DM produced during inflation.
• We show that $\Lambda$CDM, largely due to tidal stripping effects in the Milky Way, is out of reach for PTAs (as well as every other probe proposed to detect DM small scale structure).