Probing intermediate-mass black hole binaries with the lunar gravitational-wave antenna

New Moon-based gravitational-wave (GW) detector concepts, such as the lunar gravitational-wave antenna (LGWA), aim to observe GWs from 1 millihertz (mHz) to a few hertz, with optimal sensitivity in the decihertz band. Binary systems containing at least one intermediate-mass black hole (IMBH) are widely believed to generate GWs spanning from mHz to a few Hz, making them a key scientific target for the LGWA. We explore the detectability of IMBH binaries with the LGWA in this work. Considering a signal-to-noise ratio threshold of 10, our results imply that the LGWA can detect IMBH binaries up to z~O(10)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$z \sim {\mathcal{O}}(10)$$\end{document}. We further show that the LGWA can constrain the primary mass with relative errors ≲ 0.1% for binaries at z ≲ 0.5. Furthermore, we show that the IMBH binaries at z ≲ 0.1 can be used to constrain redshift with relative errors ≲ 10%, and those with m1 ∈ [104, 105] M⊙ can be localized by the LGWA to be within O(10)deg2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\mathcal{O}}(10){{\rm{deg}}}^{2}$$\end{document}.