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Kenneth I. Kellermann, National Radio Astronomy Observatory, Charlottesville, Virginia,Ellen N. Bouton, National Radio Astronomy Observatory, Charlottesville, Virginia
Some celestial objects, later recognized as quasars, were catalogued back in 1887, and their extragalactic nature was discussed as early as 1960. However, the large measured redshift of 3C 48 was rejected, largely because it implied an unrealistically high radio and optical luminosity. Instead it was assumed to be a relatively nearby, less luminous galactic radio star. Following the 1962 observations of lunar occultations of the strong radio source 3C 273 at the Parkes radio telescope and the subsequent identification with an apparent stellar object, Martin Schmidt recognized that 3C 273 had an unmistakable redshift of 0.16. Due to an error in the calculation of the radio position, the occultation position actually played no direct role in the identification of 3C 273, although it was the existence of a claimed accurate occultation position that motivated Schmidt’s 200 inch telescope investigation and his determination of the redshift. Later radio and optical measurements quickly led to the identification of other quasars with increasingly large redshifts, although the nature of the quasar redshifts remained controversial for decades.
Kenneth I. Kellermann, National Radio Astronomy Observatory, Charlottesville, Virginia,Ellen N. Bouton, National Radio Astronomy Observatory, Charlottesville, Virginia
After radio surveys of the sky uncovered a variety of discrete radio sources, there was an intense debate as to whether the radio emission originated in nearby “radio stars,” or were powerful sources located in distant galaxies? In Australia, John Bolton and Gordon Stanley discovered radio emission from two known galaxies. However, unwilling to accept the implied powerful radio emission if the sources were so distant, they instead erroneously reported that the optical counterparts to the radio sources were nearby Galactic nebulosities and not remote galaxies. Later, another Australian scientist identified the bright Cygnus A radio source with a faint galaxy and drew this identification to the attention of Mt. Wilson and Palomar astronomers, who initially either ignored or rejected the identification as being unrealistic. But, a few years later, they independently reidentified the Cygnus A radio sources, firmly establishing the nature of powerful radio galaxies and leading to wide-ranging speculation about the source of the apparent huge energy needed to power the giant radio lobes that typically extended hundreds of thousands of light years from the host galaxy.
This chapter examines late twentieth-century trends in city centre management, showing how the models of organising commercial selling space that had been developed within individual shopping complexes came increasingly to be applied to the city centre in its entirety. It considers the impact of a significant national change in planning policy as large, out-of-town shopping centres were allowed to emerge for the first time in Britain in the 1980s. The rise of out-of-town centres intensified the competitive pressures that were already present within the British urban system, forcing towns and cities to push ever harder for new forms of retail development in their own locales. Smaller urban centres were consistently disadvantaged by these dynamics and by the 1990s a narrative of ‘dying’ towns and abandoned high streets had already taken shape. Earlier post-war efforts to adapt waning industrial centres for new, consumer-driven models of growth acquired a renewed urgency and were placed at the centre of the new national policy agendas of ‘urban regeneration’ and ‘renaissance’. The chapter concludes by highlighting the inadequacy of such retail-led regeneration strategies for the most structurally disadvantaged locales.
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