(ed.). Gravitational waves (IOP, 2001)(422s).

Chapter 10LISA: A proposed joint ESA–NASAgravitational-wave missionPeter L Bender, on behalf of the LISA Study and MissionDefinition TeamsJILA, National Institute of Standards and Technology andUniversity of Colorado, Boulder, Colorado 80309-0440, USA10.1 Description of the LISA mission10.1.1 IntroductionThe evidence for supermassive black holes at the centres of quasars and activegalactic nuclei (AGNs) has been strong but not conclusive for several decades.Recently, the evidence for massive black holes in one particular AGN, in our ownGalaxy, and in the Local Group Galaxy M32 has become extremely convincing.Thus, questions concerning gravitational waves generated by the interaction ofmassive black holes with smaller compact objects and with each other havebecome of strong interest. Signals from such sources also are likely to providethe strongest possible tests of general relativity.Plans are being developed in both Europe and the USA for flying adedicated gravitational wave mission called the Laser Interferometer SpaceAntenna (LISA). The antenna will measure gravitational waves in the frequencyrange from roughly 1 µHz to 1 Hz, and thus will strongly complement the resultsexpected from ground-based detectors. The primary objectives are to obtainunique new information about massive black holes throughout the universe, andto map the metric around massive black holes (MBHs) with much higher accuracythan otherwise would be possible. Other important objectives include studies ofresolved signals from thousands of compact binary star systems in our Galaxy,and looking for a possible gravitational-wave cosmic background at millihertzfrequencies.115