Detecting ultralight dark matter in the Galactic Center with pulsars around Sgr A*

TL;DR

This paper explores how pulsar timing around Sgr A* can detect ultralight dark matter structures, such as boson clouds and soliton cores, by analyzing their gravitational effects on pulsar orbits.

Contribution

It introduces a comprehensive framework for using pulsar timing to detect ULDM structures in the Galactic Center, highlighting potential sensitivity to low-mass boson clouds.

Findings

Detection of boson clouds with mass as low as 1 solar mass is possible.

Pulsar timing can probe a wide range of soliton core masses.

Long-term monitoring with SKA could reveal ULDM effects.

Abstract

Ultralight dark matter (ULDM) model is a leading dark matter candidate that arises naturally in extensions of the Standard Model. In the Galactic Center, ULDM manifests as dense hydrogen-like boson clouds or self-gravitating soliton cores. We present the first study of the gravitational effects of these ULDM structures on pulsar orbits around Sgr A*, using pulsar timing as a precision dynamical probe, based on a comprehensive and practical framework that includes various kinds of black hole and orbital parameters. Our analysis shows that long-term pulsar monitoring -- one of the key objectives of future SKA science -- could detect a boson cloud with a total mass as low as $O(M_\odot)$ for boson mass $m \sim 10^{-18}\,\mathrm{eV}$, and probe a wide range of soliton core masses in the lower-mass regime, assuming a conservative timing precision of $\sigma_{\mathrm{TOA}}=1\,\mathrm{ms}$.