Extreme-mass-ratio burst detection with TianQin

Abstract

The capture of compact objects by massive black holes in galaxies or dwarf galaxies will generate short gravitational wave signals, called extreme-mass-ratio bursts (EMRBs), before evolving into extreme-mass-ratio inspirals. Their detection will provide an investigation of the black hole properties and shed light on astronomy and astrophysics. In this work, we investigate the detection number of the TianQin observatory on EMRBs. Our result shows that TianQin can detect tens of EMRBs events during its mission lifetime. For those detected events, we use the Fisher information matrix to quantify these uncertainties in the inference of their parameters. We consider the possible network of $\mathrm{TianQin}+\mathrm{LISA}$, and study how a network can improve parameter estimation. The result shows that, for most sources, the compact object mass, the massive black hole mass, and the massive black hole spin can be determined with a precision of the order ${10}^{\ensuremath{-}1}$ and the sky localization can be determined with a precision of 10 square degree. We further explore the gravitational wave background generated by those unsolved EMRBs and conclude that it is about ${10}^{6}$ times weaker than TianQin's sensitivity, and thus it can be ignored.