Ground-based gravitational-wave detection: now and future

In the past three years, the first generation of large gravitational-wave interferometers has begun operation near their design sensitivities, taking up the mantle from the bar detectors that pioneered the search for the first direct detection of gravitational waves. Even as the current ground-based interferometers were reaching their design sensitivities, plans were being laid for the future. Advances in technology and lessons learned from the first generation devices have pointed the way to an order of magnitude improvement in sensitivity, as well as expanded frequency ranges and the capability to tailor the sensitivity band to address particular astrophysical sources. Advanced cryogenic acoustic detectors, the successors to the current bar detectors, are being researched and may play a role in the future, particularly at the higher frequencies. One of the most important trends is the growing international cooperation aimed at building a truly global network. In this paper, I survey the state of the various detectors as of mid-2007, and outline the prospects for the future

The Laser Interferometer Gravitational Wave Observatory (LIGO) project

The LIGO (Laser Interferometer Gravitational-Wave Observatory) project is designed to open a new field of science by detecting and studying the gravitational waves from astrophysical sources, including neutron stars, black holes, and possibly, supernovae and the big bang. LIGO will consist of two scientific facilities, each incorporating an L-shaped vacuum system with 4-kilometers arms to house sensitive interferometers. A detector system consists of three interferometers, two at one site and one at the other. Each interferometer measures the motion of a set of test masses which are suspended from seismically isolated supports and free to move in response to gravitational waves. Correlations among the three interferometers will be used to eliminate local noise. LIGO is designed to support a sequence of detector systems of increasing sensitivity over the next twenty years or longer. In its initial configuration, it will have just one detector system. However, its design permits expansion to support three simultaneous detector systems. The project received funding in 1992 to begin design and construction. Sites for the two facilities (Hanford, Washington and Livingston, Louisiana) have been selected. Under the present schedule, the facilities will be completed by 1997 and initial observations will begin in 1998. Ultimately, the LIGO will be operated in coordination with interferometers in Europe and elsewhere, to form a worldwide gravitational wave observatory network

Interview with Stanley E. Whitcomb on LIGO

Interview in two sessions in March 1997 with Stanley Whitcomb, then deputy director of LIGO. Whitcomb talks about his upbringing and education in Denver, Colorado, his undergraduate studies in physics at Caltech, and his PhD work at the University of Chicago. He recalls being recruited onto the LIGO project as its first dedicated faculty member by his undergraduate advisor R. Vogt in 1980. He describes the politics and personnel, and technical and administrative challenges of LIGO’s start-up phase in the early 1980s, including the involvement of K. Thorne, the recruitment of R. Drever from Glasgow, and competing gravitational-wave initiatives headed by R. Weiss at MIT, and at Max Planck in Garching, Germany. He discusses the factors that prompted him to leave the project for private industry in 1985, his return as LIGO’s deputy director in 1991, and the NSF’s role in brokering an initially fraught LIGO partnership between Caltech and MIT under Vogt’s leadership. There is extensive discussion of Caltech and MIT’s divergent R&D approaches to gravitational-wave instrumentation and engineering in the 1980s and early ’90s, their respective merits and drawbacks, the challenges faced in resolving these differences, the technical advances of the 1990s, and prospects for future success

Squeezing in the audio gravitational wave detection band

We demonstrate the generation of broad-band continuous-wave optical squeezing down to 200Hz using a below threshold optical parametric oscillator (OPO). The squeezed state phase was controlled using a noise locking technique. We show that low frequency noise sources, such as seed noise, pump noise and detuning fluctuations, present in optical parametric amplifiers have negligible effect on squeezing produced by a below threshold OPO. This low frequency squeezing is ideal for improving the sensitivity of audio frequency measuring devices such as gravitational wave detectors.Comment: 5 pages, 6 figure

Training of Instrumentalists and Development of New Technologies on SOFIA

This white paper is submitted to the Astronomy and Astrophysics 2010 Decadal Survey (Astro2010)1 Committee on the State of the Profession to emphasize the potential of the Stratospheric Observatory for Infrared Astronomy (SOFIA) to contribute to the training of instrumentalists and observers, and to related technology developments. This potential goes beyond the primary mission of SOFIA, which is to carry out unique, high priority astronomical research. SOFIA is a Boeing 747SP aircraft with a 2.5 meter telescope. It will enable astronomical observations anywhere, any time, and at most wavelengths between 0.3 microns and 1.6 mm not accessible from ground-based observatories. These attributes, accruing from the mobility and flight altitude of SOFIA, guarantee a wealth of scientific return. Its instrument teams (nine in the first generation) and guest investigators will do suborbital astronomy in a shirt-sleeve environment. The project will invest $10M per year in science instrument development over a lifetime of 20 years. This, frequent flight opportunities, and operation that enables rapid changes of science instruments and hands-on in-flight access to the instruments, assure a unique and extensive potential - both for training young instrumentalists and for encouraging and deploying nascent technologies. Novel instruments covering optical, infrared, and submillimeter bands can be developed for and tested on SOFIA by their developers (including apprentices) for their own observations and for those of guest observers, to validate technologies and maximize observational effectiveness.Comment: 10 pages, no figures, White Paper for Astro 2010 Survey Committee on State of the Professio

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference