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Full-Text Articles in Instrumentation
Data Mining By Grid Computing In The Search For Extrasolar Planets, Oisin Creaner [Thesis]
Data Mining By Grid Computing In The Search For Extrasolar Planets, Oisin Creaner [Thesis]
Doctoral
A system is presented here to provide improved precision in ensemble differential photometry. This is achieved by using the power of grid computing to analyse astronomical catalogues. This produces new catalogues of optimised pointings for each star, which maximise the number and quality of reference stars available. Astronomical phenomena such as exoplanet transits and small-scale structure within quasars may be observed by means of millimagnitude photometric variability on the timescale of minutes to hours. Because of atmospheric distortion, ground-based observations of these phenomena require the use of differential photometry whereby the target is compared with one or more reference stars. …
Why Is An Einstein Ring Blue?, Jonathan Blackledge
Why Is An Einstein Ring Blue?, Jonathan Blackledge
Articles
Albert Einstein predicted the existence of `Einstein rings' as a consequence of his general theory of relativity. The phenomenon is a direct result of the idea that if a mass warps space-time then light (and other electromagnetic waves) will be `lensed' by the strong gravitational field produced by a large cosmological body such as a galaxy. Since 1998, when the first complete Einstein ring was observed, many more complete or partially complete Einstein rings have been observed in the radio and infrared spectra, for example, and by the Hubble Space Telescope in the optical spectrum. However, in the latter case, …
Temperature Dependence Of Stark Width Of The 463.054 Nm Nii Spectral Line, Vladimir Milosavljevic, Ruzica Konjevic, Stevan Djenize
Temperature Dependence Of Stark Width Of The 463.054 Nm Nii Spectral Line, Vladimir Milosavljevic, Ruzica Konjevic, Stevan Djenize
Articles
Stark width of the 463.054 nm singly ionized nitrogen spectral line, that belong to transition, have been measured in a linear pulsed, low pressure, arc discharge. The working gas was helium-nitrogen-oxygen mixture. Electron densities of 0.751023 to 1.451023 were determined in the electron temperature range between 30000 K - 38000 K. The measured values have been compared with our calculated data, using the modified semiempirical approximation. On the basis of the agreement among experimental and theoretical Stark width data, the isolated 463.054 nm NII spectral line can be recommended as convenient spectral line for plasma diagnostics.