Restrictions to the galaxy evolutionary models from the Hawaiian Deep Fields SSA13 and SSA22 |
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| Authors: | J A L Aguerri I Trujillo |
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| Institution: | Astronomisches Institut der Universität Basel, Venusstrasse 7, CH-4102 Binningen, Switzerland and; Instituto de Astrofísica de Canarias, E38200 La Laguna, Tenerife, Spain |
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| Abstract: | Quantitative structural analysis of the galaxies present in the Hawaiian Deep Fields SSA13 and SSA22 is reported. The structural parameters of the galaxies have been obtained automatically by fitting a two-component model (Sérsic r 1/ n bulge and exponential disc) to the surface brightness of the galaxies. The galaxies were classified on the basis of the bulge-to-total luminosity ratio ( B / T ) . The magnitude selection criteria and the reliability of our method have been checked by using Monte Carlo simulations. A complete sample of objects up to redshift 0.8 has been achieved. Spheroidal objects (E/S0) represent ≈33 per cent and spirals ≈41 per cent of the total number of galaxies, while mergers and unclassified objects represent ≈26 per cent. We have computed the comoving space density of the different kinds of object. In an Einstein–de Sitter universe, a decrease in the comoving density of E/S0 galaxies is observed as redshift increases (≈30 per cent less at z =0.8) , while for spiral galaxies a relatively quiet evolution is reported. The framework of hierarchical clustering evolution models of galaxies seems to be the most appropriate to explain our results. |
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| Keywords: | galaxies: distances and redshifts galaxies: evolution galaxies: fundamental parameters galaxies: photometry |
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