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Дата изменения: Tue Jul 3 01:00:13 2001
Дата индексирования: Sat Dec 22 04:46:17 2007
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Поисковые слова: dark energy
Example Observing Projects



EXAMPLE OBSERVING PROJECTS
(Taken from the NAIC/NRAO Single Dish Summer School 06/01)



  • HI spectral-line observations of galaxies (Karen O'Neil)
    Measuring the width, flux, etc. of the HI profile of two galaxies, using some combination of : dwarf emission line, HVC emission line, spiral emission line, and spiral absorption line.

    This project was designed to demonstrate the fundamentals of spectral line observing and position switching. The observers would have to run a system check by doing a cross-scan on a standard calibrator, and then do two 4 minute ON/OFF pairs, one on each galaxy. Additionally, the "spare boards" could be set-up to look for OH lines during the HI observations. Lack of observation of OH lines (when this is the case) would be used to demonstrate the idea of setting upper limits on observations. Additionally, the cal values observed would be used to set the telescope temperature at the time of observation. The types of galaxies observed in this project are being kept open and will be determined when the project LST is known.

  • IRAS 19566+3423 (B.M. Lewis)
    Between 1988 and 1999 the velocity ranges covered by the 1612, 1665 and 1667 MHz OH emission lines of the IRAS source 19566+3423 more than doubled (from ~12 km/s to ~30 km/s). The peak intensities in the 1612 and 1665 MHz lines are now of order 3 Jy, though much of the emission is in the 30-300 mJy range.

    The purpose of fresh observations is to check whether there is an ongoing secular increase in the velocity range of any of these lines. These observations need to be made with sufficient sensitivity (~10 mJy), with appropriate bandwidth and observing mode, as well as simultaneously in three different frequencies. The object is close enough to our zenith angle limits to require thought and care at the telescope -- maximum access time being 100 minutes on any night. Copies of the three spectra plotted against velocity will be available to inform the planning of the experiment, and to provide a comparison.

    Last updated 02 July, 2001