Pulsar timing residual induced by ultralight vector dark matter

TL;DR

This paper investigates how ultralight vector dark matter causes distinctive oscillations in spacetime detectable via pulsar timing arrays, revealing unique angular patterns and larger amplitudes compared to scalar dark matter.

Contribution

It introduces the effects of ultralight vector dark matter on pulsar timing residuals, highlighting their unique angular dependence and enhanced amplitude.

Findings

Oscillations occur at nHz frequencies detectable by pulsar timing.

Vector dark matter induces larger signals than scalar dark matter.

Distinct angular dependence differentiates vector from scalar dark matter signals.

Abstract

We study the ultralight vector dark matter with a mass around $10^{-23}\,\mathrm{eV}$. The vector field oscillating coherently on galactic scales induces oscillations of the spacetime metric with a frequency around nHz, which is detectable by pulsar timing arrays. We find that the pulsar timing signal due to the vector dark matter has nontrivial angular dependence unlike the scalar dark matter and the maximal amplitude is three times larger than that of the scalar dark matter.