"LISA and the Promise of Low-Frequency Gravitational
Wave Astronomy"
Gravitational waves offer a window on the universe which
complements
the windows provided by electromagnetic radiation and
neutrinos. Just
as different frequencies of the electromagnetic spectrum
highlight
different astrophysical phenomena, different frequency
ranges of
gravitational radiation will highlight different kinds
of objects.
The Laser Interferometer Space Antenna (LISA), planned
for launch in
2010, will detect and measure gravitational radiation
from
astronomical sources at frequencies 0.0001 Hz to 0.1
Hz (compared to
10-1000 Hz for ground-based detectors). LISA will detect
continuous
signals from: thousands of interesting binary stars in
the Milky Way,
merging of supermassive black holes in the nuclei of
merging galaxies
at redshifts from 0 to 100, and gravitational radiation
from compact
stars scattered into supermassive black holes.
The latter can provide
tests of strong-field relativity of unprecedented precision.
We will
conclude with an outline of some of the remarkable possibilities
for
the subsequent expansion of low-frequency gravitational
wave
astronomy.