Characterizing accreting double white dwarf binaries with the Laser Interferometer Space Antenna and Gaia

TL;DR

This paper presents a method to characterize mass-transferring double white dwarf binaries using combined data from LISA and Gaia, enabling mass inference and orbital evolution analysis for a significant subset of systems.

Contribution

It introduces a novel approach to determine masses and orbital evolution of double white dwarf systems by combining gravitational wave and optical data, based on the mass-radius relationship.

Findings

Masses can be inferred for up to 60 systems with combined LISA and Gaia observations.

Half of these systems have mass uncertainties less than 0.2 solar masses for donors and 2.3 for accretors.

Orbital frequency evolution can be decoupled from astrophysical processes for about 50 systems.

Abstract

We demonstrate a method to fully characterize mass-transferring double white dwarf (DWD) systems with a helium-rich (He) WD donor based on the mass--radius relationship for He WDs. Using a simulated Galactic population of DWDs, we show that donor and accretor masses can be inferred for up to $\sim\, 60$ systems observed by both Laser Interferometer Space Antenna (LISA) and Gaia. Half of these systems will have mass constraints $\Delta\,M_{\rm{D}}\lesssim0.2M_{\odot}$ and $\Delta\,M_{\rm{A}}\lesssim2.3\,M_{\odot}$. We also show how the orbital frequency evolution due to astrophysical processes and gravitational radiation can be decoupled from the total orbital frequency evolution for up to $\sim 50$ of these systems.