249 research outputs found

    Interferometry meets the third and fourth dimensions in galaxies

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    Radio astronomy began with one array (Jansky's) and one paraboloid of revolution (Reber's) as collecting areas and has now reached the point where a large number of facilities are arrays of paraboloids, each of which would have looked enormous to Reber in 1932. In the process, interferometry has contributed to the counting of radio sources, establishing superluminal velocities in AGN jets, mapping of sources from the bipolar cow shape on up to full grey-scale and colored images, determining spectral energy distributions requiring non-thermal emission processes, and much else. The process has not been free of competition and controversy, at least partly because it is just a little difficult to understand how earth-rotation, aperture-synthesis interferometry works. Some very important results, for instance the mapping of HI in the Milky Way to reveal spiral arms, warping, and flaring, actually came from single moderate-sized paraboloids. The entry of China into the radio astronomy community has given large (40-110 meter) paraboloids a new lease on life.Comment: Virginia Trimble 2014, in IAU Symp. 309 "Galaxy in 3D across the Universe", B.L. Ziegler, F. Combes, H. Dannerbauer, M. Verdugo, Eds. (Cambridge: Cambridge Uni. Press) in press NOTE - Should be "Galaxies" not "Galaxy

    Star Formation from Spitzer (Lyman) to Spitzer (Space Telescope) and Beyond

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    A summary of JENAM 2008 Symposium 9 "Star Formation from Spitzer (Lyman) to Spitzer (Space Telescope) and Beyond", held in Vienna, 10-12 September 2008.Comment: 6 page

    A citation history of measurements of Newtons constant of Gravity

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    We created and analyzed a citation history of papers covering measurements of Newtons constant of gravity from 1686 to 2016. Interest concerning the true value of the gravitational constant was most intense in the late 90s to early 2000s and is gaining traction again in the present. Another network consisting of the same papers was created using citations from databases to display the prominence of papers on Newtons constant in the wider scientific community. In general, papers that were important in one network remained important in the other while papers that had little importance in one network remained unimportant in the other. The US contributes the most to literature on the topic both in where journals were published and where the work was done; however, many other countries, such as China, Russia, France, Germany, Switzerland, and the UK also provide many papers on Newtons G. Work done within certain countries tends to be considered more important and cited more often within that country. Recent efforts promoting international collaboration may have an impact on this trend

    Astrophysical accretion: The approach to the irrationality horizon

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    Creator’s records: The pre-history of single and binary neutron stars

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    Bursters and the quest for ‘‘cosmological effects’’

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    Some Faint Stars and a Bright One

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    The low-luminosity stars are a wild assortment - hot and cool, old and young, dense and diffuse - almost as motley a crew as the 85 astronomers who gathered at Caltech on October 15-16, 1984 to discuss them and to honor the 75th birthday of Jesse L. Greenstein
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