On detecting stellar binary black holes via the LISA-Taiji network

The detection of gravitational waves (GWs) by ground-based laser interferometer GW observatories (LIGO/Virgo) reveals a population of stellar binary black holes (sBBHs) with (total) masses up to ∼ 150 M ⊙ , which are potential sources for space-based GW detectors, such as LISA and Taiji. In this paper, we investigate in details on the possibility of detecting sBBHs by the LISA-Taiji network in future. We adopt the sBBH merger rate density constrained by LIGO/VIRGO observations to randomly generate mock sBBHs samples. Assuming an observation period of 4 years, we find that the LISA-Taiji network may detect several tens (or at least several) sBBHs with signal-to-noise ratio (SNR) > 8 (or > 15), a factor 2 − 3 times larger than that by only using LISA or Taiji observations. Among these sBBHs, no more than a few that can merge during the 4-year observation period. If extending the observation period to 10 years, then the LISA-Taiji network may detect about one hundred (or twenty) sBBHs with SNR> 8 (or > 15), among them about twenty (or at least several) can merge within the observation period. Our results suggest that the LISA-Taiji network may be able to detect at least a handful to twenty or more sBBHs even if assuming a conservative SNR threshold (15) for “detection”, which enables multi-band GW observations by space and ground-based GW detectors. We also further estimate the uncertainties in the parameter estimations of the sBBH systems “detected” by the LISA-Taiji network. We find that the relative errors in the luminosity distance measurements and sky localization are mostly in the range of 0.05 − 0.2 and 1 − 100deg 2 , respectively, for these sBBHs.