We estimate the rate at which the proposed space gravitational-wave interferometer LISA could detect intermediate-mass black hole (IMBH) binaries, that is, binaries containing a black hole in the mass range 10-100 Msolar orbiting a black hole in the mass range 100-1000 Msolar. For 1 yr integrations leading up to the innermost stable circular orbit and a signal-to-noise ratio of 10, we estimate a detection rate of only 1 per million years for 10 Msolar/100 Msolar binaries. The estimate uses the method of parameter estimation via matched filtering, incorporates a noise curve for LISA established by the LISA Science Team that is available online, and employs an IMBH formation rate model used by Miller in 2002. We find that the detectable distance is relatively insensitive to LISA arm lengths or acceleration noise but is roughly inversely proportional to LISA position errors and varies roughly as T1/2, where T is the integration time in years. We also show that while all IMBH systems in this mass range may be detected in the Virgo cluster up to 40 yr before merger, none can be detected there earlier than 400 yr before merger. An extended LISA mission that enabled 10 yr integrations could detect IMBH systems at the Virgo cluster 1000 yr before merger, and systems in Galactic globular clusters 1 million yr before merger. We compare and contrast these estimates with earlier estimates by Miller.
The Astrophysical Journal
- Pub Date:
- August 2004
- Black Hole Physics;
- Gravitational Waves;
- General Relativity and Quantum Cosmology
- 6 pages, 3 figures, added discussion of implications of 10-year LISA mission, accepted for publication in The Astrophysical Journal