Gravitational wave astronomy, relativity tests, and massive black holes

Abstract

Abstract. The gravitational wave detectors that are operating now are looking for several kinds of gravitational wave signals at frequencies of tens of Hertz to kilohertz. One of these is mergers of roughly 10 M BH binaries. Sometime between now and about 8 years from now, it is likely that signals of this kind will be observed. The result will be strong tests of the dynamical predictions of general relativity in the high field regime. However, observations at frequencies below 1 Hz will have to wait until the launch of the Laser Interferometer Space Antenna (LISA), hopefully only a few years later. LISA will have 3 main objectives, all involving massive BHs. The first is observations of mergers of pairs of intermediate mass (100 to 10 5 M ) and higher mass BHs at redshifts out to roughly z=10. This will provide new information on the initial formation and growth of BHs such as those found in most galaxies, and the relation between BH growth and the evolution of galactic structure. The second objective is observations of roughly 10 M BHs, neutron stars, and white dwarfs spiraling into much more massive BHs in galactic nuclei. Such events will provide detailed information on the populations of such compact objects in the regions around galactic centers. And the third objective is the use of the first two types of observations for testing general relativity even more strongly than ground based detectors will. As an example, an extreme mass ratio event such as a 10 M BH spiraling into a galactic center BH can give roughly 10 5 observable cycles during about the last year before merger, with a mean relative velocity of 1/3 to 1/2 the speed of light, and the frequencies of periapsis precession and Lense-Thirring precession will be high. The LISA Pathfinder mission to prepare for LISA is scheduled for launch in 2011.

Alternative Uses for Quantum Systems and Devices

“…Information about interstellar gas in high-redshift galaxies [2] is relevant in providing the tools for the numerical simulation of pressure and energy and verifying the behavior of their celestial bodies. The evolution of galactic structures and their compact objects in the vicinity of galaxy centers, as well as the refinements of General Relativity (GR)tests [3], can be achieved by accurately measuring the frequencies of the periapsis and Lense-Thirring precessions. By means of a single, linear interferometer [4], the evolution of a binary system can be followed as described by their leading-order quadrupole gravitational radiation by calculating the source rate (of gravitational radiation) and the observation range.…”

Possible LISA follow-on mission scientific objectives

“…One of the main scientific objectives for the originally proposed Laser Interferometer Space Antenna (LISA) mission [2,3] was to learn as much as possible about the initial formation and growth of the massive black holes (MBHs) that are present today in the centers of most galaxies [4][5][6][7][8]. A number of scenarios have been presented for how the initial seed black holes (BHs) were formed at early times, and then grew by accretion and mergers up until now.…”