Taiji Program: Gravitational-Wave Sources

TL;DR

Taiji targets low-frequency gravitational waves in the range $\$0.1\,\mathrm{mHz}$ to $1\,\mathrm{Hz}$ and reviews sources from compact binaries and early-Universe SGWBs. It forecasts Taiji detection rates and uses the Fisher information matrix to forecast MBHB parameter accuracies, including the chirp mass $M_c$, symmetric mass ratio $\eta$, luminosity distance $d_L$, and sky localization $\Omega_s$ for equal-mass mergers at $z=1$. The work highlights MBHBs as standard sirens for cosmology, EMRIs/IMRIs as strong-field GR probes, and Galactic binaries as both foreground and astrophysical tools, with thousands of Galactic binaries and tens of MBHB/EMRI events per year expected, plus potential SGWB detections from the early Universe. Overall, Taiji promises to advance gravitational-wave cosmology and early-Universe physics through diverse sources including inflationary, preheating/reheating, and phase-transition backgrounds.

Abstract

We review potential low-frequency gravitational-wave sources, which are expected to be detected by Taiji, a Chinese space-based gravitational-wave detector, estimate the detection rates of these gravitational-wave sources and present the parameter estimation of massive black hole binaries.

Figures (1)

• Figure 1: Strain sensitivity (left) and energy density (right) for Taiji with the spacecraft separation $3\times10^9$ m, telescope diameter $0.4$ m, laser power $2$ W, position noise $8$ pm Hz$^{-1/2}$, and acceleration noise $3\times 10^{-15}$ m s$^{-2}$ Hz$^{-1/2}$.