4 research outputs found
The Search for Gravitational Waves
Experiments aimed at searching for gravitational waves from astrophysical
sources have been under development for the last 40 years, but only now are
sensitivities reaching the level where there is a real possibility of
detections being made within the next five years. In this article a history of
detector development will be followed by a description of current detectors
such as LIGO, VIRGO, GEO 600, TAMA 300, Nautilus and Auriga. Preliminary
results from these detectors will be discussed and related to predicted
detection rates for some types of sources. Experimental challenges for detector
design are introduced and discussed in the context of detector developments for
the future.Comment: 21 pages, 7 figures, accepted J. Phys. B: At. Mol. Opt. Phy
Extended Theories of Gravity and their Cosmological and Astrophysical Applications
We review Extended Theories of Gravity in metric and Palatini formalism
pointing out their cosmological and astrophysical application. The aim is to
propose an alternative approach to solve the puzzles connected to dark
components.Comment: 44 pages, 11 figure
Gravitational wave astronomy: the current status
In the centenary year of Einstein\u2019s General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein\u2019s first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan, which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1\u20135 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry