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New diagnostic methods for emission-line galaxies in deep surveys

Claudia S. Rola·Elena Terlevich·Roberto J. Terlevich
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Abstract

We present new quantitative classification methods for emission-line galaxies, which are specially designed to be used in deep galaxy redshift surveys. A good segregation between starbursts and active galactic nuclei, i.e. Seyferts 2s and LINERs, is obtained from diagnostic diagrams involving the [O II]λ3727 Å, [Ne III]\lambda3869 Å, Hβand [O III]\lambda5007 Årelative intensities or the [O II]λ3727 Åand Hβequivalent widths. Furthermore, the colour index of the continuum underlying [O II]λ3727 Åand Hβprovides an additional separation parameter between the two types of emission-line galaxies. We have applied the equivalent widths method to the 0 < z \leq 0.3 emission-line galaxies of the Canada-France Redshift Survey. Our results are in very good agreement with those obtained using the standard diagnostic diagrams including all the strong optical emission-line intensity ratios.

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Claudia S. Rola, Elena Terlevich, Roberto J. Terlevich. 1997-06-02. New diagnostic methods for emission-line galaxies in deep surveys. https://doi.org/10.1093/mnras%2F289.2.419

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