Are stellar-mass black-hole binaries too quiet for LISA?

Abstract

The progenitors of the high-mass black-hole mergers observed by LIGO and Virgo are potential LISA sources and promising candidates for multiband GW observations. In this letter, we consider the minimum signal-to-noise ratio these sources must have to be detected by LISA bearing in mind the long duration and complexity of the signals. Our revised threshold of ρthr ∼15 is higher than previous estimates, which significantly reduces the expected number of events. We also point out the importance of the detector performance at high frequencies and the duration of the LISA mission, which both influence the event rate substantially.