Fundamental Physics with Pulsars around Sagittarius A$^\star$

TL;DR

Discovering and timing pulsars near Sagittarius A* can enable unique tests of fundamental physics and dark matter, despite perturbations complicating measurements.

Contribution

This work discusses the potential of pulsar timing around Sgr A* for fundamental physics and introduces a numerical model to account for perturbations.

Findings

Timing pulsars near Sgr A* can test gravity and dark matter.

Mass perturbations affect the gravitational measurements.

A numerical pulsar timing model is being developed.

Abstract

Searching for radio pulsars orbiting around the Galactic centre black hole (BH), Sagittarius A$^\star$ (Sgr A$^\star$), represents a holy grail goal for large-area radio telescopes, in particular for the Square Kilometre Array. Follow-up timing observation of such a PSR-Sgr A$^\star$ binary system with an orbital period $\lesssim O(1\,{\rm year})$ will bring forward a handful of new tests on different aspects of fundamental physics that are barely accessible with other means. However, mass perturbation in the Galactic centre harms the gravitational cleanness of PSR-Sgr A$^\star$ systems. In order to flexibly account for perturbations, a numerical pulsar timing model is gradually being built, which can be used to probe the spacetime around Sgr A$^\star$ BH and study the nature of dark matter.