Gravitational radiation

Characteristic strain The gravitational wave strain of a signal at some characteristic frequency times the square root of the number of cycles over which the signal is observed near that frequency. 

Detector sensitivity Characteristic strain due to gravitational waves that would exceed instrumental strain noise in a detector. 

Gravitational wave strain The fractional change in the distance between two free-falling bodies produced by a gravitational wave as it passes the bodies. 

Resonant-mass detector A massive cylinder of aluminium, or nobium crystal, suspended in vacuum and mechanically isolated from its surroundings. When a gravitational wave impinges on the cylinder, the relative accelerations excite the cylinder s natural modes of oscillation. 

Tidal distortion The deformation of a massive body by the gravitational field produced by other bodies. 

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Until now, no certain evidence of the existence of GWs has been found. However Hulse and Taylor, studying the PSR 1913+13 binary system of pulsars, found that experimental data were fully coherent with the hypothesis that part of the system energy was lost through gravitational radiation [52-54],... 

As just described, the most precise measurements of masses come from double neutron star systems. There are currently five such systems known, three of which will coalesce due to gravitational radiation in less than the age of the universe, 1010 yr (Taylor 1994). These three systems in particular allow very precise measurements of the masses of the components, which are between 1.33 M and 1.45 M0 (Thorsett Chakrabarty 1999). The other two double neutron star systems also have component masses consistent with a canonical 1.4 M . It has been suggested that the tight grouping of masses implies that the maximum mass of a neutron star is 1.5 M0 (Bethe Brown 1995). However, it is important to remember that double neutron star systems all have the same evolutionary pathway and thus the similar masses may simply be the result of a narrow selection of systems. 

Primoridal gravitational radiation, Grischuk 1974 (43), associated with scenarios we would now call inflation, Starobinsky 1979 (44). And if you declare that inflation had not yet been invented, you will have the givers of several major prizes on your side. 

Primordial gravitational radiation means the sort that comes from stuff sloshing around in the early universe. As with the case of PBHs, there are limits well below Qgr = 1 in many regimes (wavelength rather than mass in this case, [58]), but also still some for which limits are not very tight, except in the generic sense that the universe acts like most of its positive pressure stuff is matter, with density proportional to (1+z)3 rather than radiation with density proportional to (1+z)4. 

Relativistic Gravitation and Gravitational Radiation, edited by J.-A. Marck and J.-P. Lasota (ISBN 0 521 59065 5)... 

Much of the microwave radiation from celestial radio sources outside the Galaxy is believed to originate from electrons moving in curved paths in celestial magnetic fields it is also called synchrotron radiation as it is analogous to the radiation occurring in a synchrotron. Synchrotron radiation is also predicted to exist for gravitational radiation. 

R.L. Foreward Wideband laser-interferometer gravitational radiation experiment. Phys. Rev. D 17, 379 (1978)... 

Vest, C. M. (1979). Holographic Interferometry, Wiley, New York. Weiss, R. (1999). Gravitational radiation. Rev. Mod. Phys. 71, S187-S196. 

The methods used to observe gravitational radiation suggest that four frequency bands be identified. The bands... 

It is believed that gravitational radiation from the r-modes in nascent neutron stars is the mechanism by which newborn neutron stars, which could be rotating at near their breakup speed ( 1 kHz), lose most of their angular momentum. The result is the slowly spinning neutron stars that are observed. R-modes could produce nearly monochromatic gravitational radiation with a characteristic strain as large as /tchar 10 at frequencies of kHz and distances of 10 Mpc, lasting for several tens of seconds. 

FIGURE 3 Sources of gravitational radiation and detector sensitivities. 

Another plausible mechanism for the emission of gravitational radiation in very rapidly spinning stars is accretion-driven asymmetries. The principal axes of the moment of inertia can be driven away from the rotational axes by accretion from a companion star. Accretion can produce relatively strong radiation, since the amplitude is related to the accretion rate rather than to structural effects in the star. 

The merger and ringdown of the black hole will produce a burst of gravitational radiation that is in the HF band for stellar-mass black holes, or in the LF band for supermassive black holes. Typically, the black holes will... 

Muller, E. (1997). Gravitational radiation from core-collapse supernovae. Classical Quantum Gravity 14, 1455-1460. 

Peters, P. C., and Mathews, J. (1963). Gravitational radiation from point masses in a Kepletian orbit. Physical Rev. 131,435 140. 

Thorne, K. S. (1997). Gravitational radiation A new window onto the universe. http //arXiv.org/abs/gr-qc/9704042. 

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