Fast resolution of Galactic binaries in LISA data

Abstract

Resolving individual gravitational waves from tens of millions of double white dwarf (DWD) binaries in the Milky Way is a challenge for future space-based gravitational wave detection programs. By using previous data to define the priors for the next search, we propose an accelerated approach of searching the DWD binaries, and demonstrate its efficiency based on the GBSIEVER detection pipeline. Compared to the traditional GBSIEVER method, our method can obtain $\ensuremath{\sim}50%$ of sources with 2.5% of the searching time for LDC1-4 data. In addition, we find that both methods have a similar ability to detect the Milky Way structure by their confirmed sources. The relative error of distance and chirp mass is about 20% for DWD binaries whose gravitational wave frequency is higher than $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }\mathrm{Hz}$, even if they are close to the Galactic Center. Finally, we propose a signal-to-noise ratio (SNR) threshold for LISA to confirm the detection of DWD binaries. The threshold should be 16 when the gravitational wave frequency is lower than $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }\mathrm{Hz}$ and 9 when the frequency range is from $4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ to $1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}\text{ }\text{ }\mathrm{Hz}$.