Automatische Suche nach Quasaren.
Abstract
The basic principles and methods of a search for northern-sky quasar candidates on objective-prism and direct-image photographic plates obtained with the 80-cm Schmidt telescope at Calar Alto are reviewed. The cosmological and astrophysical importance of quasars is reviewed; the observational techniques are outlined; and particular attention is given to the microdensitometer scanning procedure, the data-reduction and candidate-selection algorithms, and the characteristic features of quasar spectra. Although some candidates can be identified as quasars on the basis of their Schmidt spectra alone, others require reobservation with a high-resolution grating spectrograph on the 3.5-m telescope. The major achievement of the survey to date is the discovery of the very bright quasar HS1700+6416, with z = 2.74 and m(v) = 16.1 mag; the increase in UV flux with decreasing wavelength observed by the IUE in this object is briefly discussed.
- Publication:
-
Sterne und Weltraum
- Pub Date:
- May 1989
- Bibcode:
- 1989S&W....28..283B
- Keywords:
-
- Astronomy;
- Quasars;
- Microdensitometers;
- Photographic Plates;
- Ultraviolet Spectra;
- Astronomy;
- Quasars: Surveys