Bayesian sensitivity of binary pulsars to ultra-light dark matter

TL;DR

This paper develops a Bayesian method to analyze binary pulsar data for ultra-light dark matter detection, extending sensitivity estimates across all masses and combining multiple observations, with promising future detection prospects.

Contribution

The authors introduce a semi-analytical Bayesian approach that broadens sensitivity analysis for ultra-light dark matter using binary pulsars beyond previous resonance-limited studies.

Findings

Next-generation radio telescopes will improve sensitivity to ultra-light dark matter coupling.

Sensitivity will surpass solar-system constraints around mass $m\sim10^{-21}$ eV.

Method enables detection sensitivity for all dark matter masses, not just near resonance.

Abstract

Ultra-light dark matter perturbs the orbital motion of binary pulsars, in particular by causing peculiar time variations of a binary's orbital parameters, which then induce variations in the pulses' times-of-arrival. Binary pulsars have therefore been shown to be promising detectors of ultra-light dark matter. To date, the sensitivity of binary pulsars to ultra-light dark matter has only been studied for dark matter masses in a narrow resonance band around a multiple of the binary pulsar orbital frequency. In this study we devise a two-step, bayesian method that enables us to compute semi-analytically the sensitivity for all masses, also away from the resonance, and to combine several observed binaries into one global sensitivity curve. We then apply our method to the case of a universal, linearly-coupled, scalar ultra-light dark matter. We find that with next-generation radio observatories the sensitivity to the ultra-light dark matter coupling will surpass that of solar-system constraints for a decade in mass around $m\sim10^{-21}$ $\text{eV}$, even beyond resonance.