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

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 analyse both a sample of currently known 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 ∼ 100 known DWDs; GW signals of these binaries can be modelled 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 accuracy of ∼ 10 −7 and ∼ 0.2 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 configuration 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-lead 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.

Exploring the spectral shape of gravitational waves induced by primordial scalar perturbations and connection with the primordial black hole scenarios

“…Fitting functions regarding the sensitivity curves for LISA, aLIGO and ET are provided by [77]; for DECIGO and BBO we consulted [78] and adjusted the sensitivities of these experiments to current values and expectations; for TianQin we used the fitting function provided in Ref. [79].…”

The Gravitational Wave Universe Toolbox: A software package to simulate observation of the Gravitational Wave Universe with different detectors

“…Among those Galactic binaries, close double white dwarfs (DWDs) are the dominant, and are long expected to be promising targets for LISA and other space-borne GW detectors (e.g. Nelemans et al 2001;Yu & Jeffery 2010;Nissanke et al 2012;Toonen et al 2012;Korol et al 2017;Lamberts et al 2019;Huang et al 2020).…”

“…Beside the synthetic catalogue, we also include a catalogue of 81 known DWDs (Huang et al 2020) as verification binaries (VBs, see also Kupfer et al 2018). Those VBs are plotted along in figure 6 with star markers.…”

Sky localization of space-based gravitational wave detectors

“…The precision of the parameter estimation and the sky localization of equal mass SMBH binary systems with masses in the range 10 5 − 10 7 M for TianQin was discussed in [24]. It was further argued that the LISA-TianQin network can improve the sky localization of Galactic double white dwarf binaries up to 3 orders of magnitude [25], if compared with single TianQin observation.…”