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 ρ thr ∼ 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.

Gravitational-wave Detection and Parameter Estimation for Accreting Black-hole Binaries and Their Electromagnetic Counterpart

“…In the LISA-only case for SOBHBs, we assume that a single event within the catalogue is detected if either of the following conditions occurs (Moore, Gerosa and Klein 2019;Tamanini et al 2019) t c < 10 yr and SNR ≥ 9.5 .…”

“…t c < 100 yr and SNR ≥ 15, or t c > 100 yr and SNR ≥ 10 , where the latter SNR threshold is lower because binaries with long merger times are accurately described by Newtonian waveforms in the LISA band(Mangiagli et al 2019) and can be therefore detected by a different search strategy(Tamanini et al 2019), akin e.g. to the one used for white-dwarf binaries.In the LISA+Earth case, the SNR threshold is lower for events that can be detected on Earth(Moore, Gerosa and Klein 2019;Tamanini et al 2019) …”

Science case for the Einstein telescope

“…This highlights the importance of the sensitivity curve at high frequencies, as well as of the other assumptions entering the estimates. Note that the analysis of[147] is restricted to binary BHs with merger times up to 100 yr. As discussed in[147], a numerous population with larger merger times could also be present. For these wide and slowly inspiraling binaries, the signal is closer to monochromatic and data analysis simplifies considerably, allowing for a lower SNR threshold.…”

Parameterized and Consistency Tests of Gravity with GravitationalWaves: Current and Future

“…The former will also allow one to optimize ground-based GW detector sensitivities to further improve upon tests of GR [98]. On the other hand, successful observations of merger-ringdown events with ground-based detectors could allow one to revisit old space-based data and recover sub-threshold events [99], lowering the SNR threshold from 15 to 9 [100] for space-based detectors, which can result in an increased total number of detections [96,99,100]. Finally, the multi-band GW observations of coalescence events have been shown to improve upon the measurement accuracy of several binary parameters, in particular the masses, spins and sky-positions [90,92,96,101].…”