Science with the TianQin Observatory: Preliminary results on Galactic double white dwarf binaries

TL;DR

This paper evaluates TianQin's ability to detect and analyze Galactic double white dwarf binaries using gravitational waves, highlighting its potential to vastly expand the known sample and improve parameter estimation.

Contribution

It provides the first detailed assessment of TianQin's detection prospects for DWDs, including known and synthetic populations, and explores configurations to enhance performance.

Findings

TianQin can detect 12 of ~100 known DWDs as verification sources.

Potential to detect up to 10,000 DWDs in the Milky Way.

Network configurations significantly improve detection accuracy and sky localization.

Abstract

We explore the prospects of detecting of Galactic double white dwarf (DWD) binaries with the space-based gravitational wave (GW) observatory TianQin. In this work, we analyze both a sample of currently known DWDs and a realistic synthetic population of DWDs to assess the number of guaranteed detections and the full capacity of the mission. We find that TianQin can detect 12 out of $\sim100$ known DWDs; GW signals of these binaries can be modeled in detail ahead of the mission launch, and therefore they can be used as verification sources. Besides we estimate that TianQin has potential to detect as many as $10^4$ DWDs in the Milky Way. TianQin is expected to measure their orbital periods and amplitudes with accuracies of $\sim10^{-7}$ and $\sim0.2$, respectively, and to localize on the sky a large fraction (39%) of the detected population to better than 1 deg$^2$. We conclude that TianQin has the potential to significantly advance our knowledge on Galactic DWDs by increasing the sample up to 2 orders of magnitude, and will allow their multi-messenger studies in combination with electromagnetic telescopes. We also test the possibilities of different configurations of TianQin: (1) the same mission with a different orientation, (2) two perpendicular constellations combined into a network, and (3) the combination of the network with the ESA-led Laser Interferometer Space Antenna. We find that the network of detectors boosts the accuracy on the measurement of source parameters by 1-2 orders of magnitude, with the improvement on sky localization being the most significant.