Probing Dark Matter's Gravitational Effects Locally with TianQin

Abstract

In this study, we explore the potential of using TianQin missions to probe the local gravitational effects of dark matter. The TianQin project plans to launch satellites at both low and high orbits. High-precision orbit determination is expected to aid in detecting Earth's gravity or gravitational waves. By comparing the derived masses in low and high orbits, it is possible to constrain the amount of dark matter between the two spheres, hence placing a local constraint on dark matter's gravitational effect. Our results show the capability of TianQin in detecting the density of dark matter around Earth, with an ultimate sensitivity to a value of $10^{-8}\,\,{\rm kg\,\,m^{-3}}$. This detection limit surpasses the estimated bounds for the solar system and the observation results for our Galaxy by approximately 7 and 14 orders of magnitude, respectively.

Figures (2)

• Figure 1: Schematic diagram of LDM detection. The radius of the Earth $R_{\rm E}\simeq6400\,\,\rm km$, the shadowed part is represented as the measured dark matter region.
• Figure 2: Monte Carlo simulations for the LDM density. Vertical dashed lines on the distribution mark the quantiles [16%, 50%, 84%], with the red line representing the true value. The blue band covers the theoretical measurement uncertainty.