T Sumner, P Wass, D Hollington
eLISA is a mission under development as the European Space Agency’s third Large class mission in its Cosmic Vision programme. The goal is to explore the science theme ‘The Gravitational Universe’ by studying gravitational waves emitted by compact objects in the near and distant universe. Gravitational wave observations offer a new and unique means of studying our Universe and probing the intricate details of General Relativity. As well as enlarging our understanding of physics and astronomy, they offer an unprecedented opportunity to discover completely new physics unprobed by electromagnetic observatories.
The evolved Laser Interferometer Space Antenna (eLISA) is a satellite mission which will observe gravitational waves in the frequency range between 0.1mHz and 0.1Hz from a wide variety astrophysical sources. This will allow precision tests of General Relativity and a new means of doing astrophysics and cosmology.
More details about the project
Fundamental Physics:
eLISA will enable tests of General Relativity to unprecedented precision. In particular it will provide:
- A guaranteed direct detection of gravitational waves unless they propagate in a way not described by General Relativity. Stellar binary systems exist in the Milky Way which are guaranteed ‘calibration’ sources for the eLISA observatory.
- Test of propagation of gravitational waves at the speed of light
- Measurement of polarisation states of gravitational waves
- Mapping of the space-time metric around super massive black-holes by the tracing the gravitational signal generated by the inspiral of stellar mass compact objects.
- Detailed tests of numerical relativity predictions
Astrophysics:
eLISA will open up a new window on the universe for astrophysical observation:
- Population study of thousands of compact white-dwarf binary systems in the Milky Way. This will provide information about the evolution, life cycle and distribution of these systems which eventually give rise to Type Ia supernovae.
- Mergers of massive black-holes at the centres of galaxies will be observed from throughout the lifetime of the universe allowing a study of the progenitors of massive black holes, the galaxy merger history of the universe, as well as the energy loss processes associated with the merger coalescence and ringdown of SMBHs.
Cosmology:
eLISA provides an opportunity to probe a stochastic background of gravitational waves originating in TeV scale processes in the very early universe. Such a detection would revolutionise our understanding of exotic physics in the first moments after the big bang such as:
- Amplification of quantum vacuum fluctuations during inflation
- Phase transitions leading to cosmic strings bursts
