An automatic approach for selecting new Hα emission-line galaxies


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Alonso, O. and Zamorano Calvo, Jaime and Rego Fernández, Manuel and Gallego Maestro, Jesús and Vitores, A.G. (1994) An automatic approach for selecting new Hα emission-line galaxies. In Astronomy from wide-field imagings. Kluwer Academic Publ., pp. 611-614. ISBN 0-7923-2878-7

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The most unambiguous way to discover new emission-line galaxies (ELGs) is directly by the presence of their lines, using objective-prism plates of adequate resolution. The first survey using this technique was developed by Smith in 1975 with the 0.6 m CTIO Curtis Schmidt Telescope. The Universidad Complutense de Madrid (UCM) is carrying out a survey of ELGs with the Schmidt Telescope at Calar Alto (Almería, Spain) using the presence of Ha in emission in IIIa-F prism plates as selection criterion. The observational procedure and results are described in Rego et al. 1989; Zamorano et al. 1990; Zamorano et al. 1993.
The standard procedure is to scan the plates by eye, with a low-power binocular microscope. The use of different subjective criteria in the visual inspection can produce biased samples. Moreover, the visual scan does not produce any quantitative measure but only a sample of candidates. Therefore, in order to obtain an observer-independent sample and to extract the largest amount of information from the original plates, 2 plates have been scanned with the MAMA machine 1 (Guibert & Moreau 1991; Moreau 1992) with the aim of developing an automatic procedure to detect ELGs spectra.

Item Type:Book Section
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© IAU-Kluwer 1994. Symposium of the International-Astronomical-Union (161st. 1993. Potsdam/Germany).

Uncontrolled Keywords:Objective-prism survey
Subjects:Sciences > Physics > Astrophysics
Sciences > Physics > Astronomy
ID Code:61626
Deposited On:23 Jul 2020 10:23
Last Modified:23 Jul 2020 10:23

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