| Type de publication : |
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Articles dans des revues avec comité de lecture |
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| Domaine : |
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Physique/Astrophysique/Cosmologie et astrophysique extra-galactique
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| Titre : |
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The ESO-Sculptor Survey: Evolution of late-type galaxies at redshifts 0.1-0.5 |
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| Auteur(s) : |
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Valerie de Lapparent, Stephane Arnouts 1, Gaspar Galaz, Sandro Bardelli |
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| Laboratoire : |
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| Résumé : |
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[ABRIDGED] Using the Gaussian+Schechter composite luminosity functions measured from the ESO-Sculptor Survey (de Lapparent et al. 2003), we obtain evidence for evolution in the late spectral class containing late-type Spiral (Sc+Sd) and dwarf Irregular (dI) galaxies. This evolution is detected as an increase of the Sc+Sd+dI galaxy density which can be modeled as either n(z)~1+3(z-0.15) or n(z) ~ (1+z)^2 using the currently favored cosmological parameters Omega_m=0.3 and Omega_Lambda=0.7, with an uncertainty in both evolution rates of order of unity. For Omega_m=1.0 and Omega_Lambda=0.0, the linear and power-law evolution rates are 4 and 2.5 resp. Both models yield a good match to the ESS BVRc redshift distributions to 21-22 mag and to the number-counts to 23-23.5 mag, which probe the galaxy distribution to redshifts z~0.5 and z~1.0 resp. This analysis illustrates how Gaussian+Schechter composite luminosity functions provide more robust constraints on the evolution rate than pure Schechter functions. The detected density evolution indicates that mergers could play a significant role in the evolution of late-type Spiral and dwarf Irregular galaxies. However, the ESO-Sculptor density increase with redshift could also be caused by a ~1 mag brightening of the Sc+Sd+dI galaxies at z~0.5 and a ~1.5-2.0 mag brightening at z~1, which is compatible with the expected passive brightening of Sc galaxies at these redshifts. Distinguishing between luminosity and density evolution is a major difficulty as these produce the same effect on the redshift and magnitude distributions. The detected evolution rate of the ESO-Sculptor Sc+Sd+dI galaxies is nevertheless among the range of measured values from the other existing analyses, whether they provide evidence for density or luminosity evolution. |
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Langue du texte
intégral : |
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Anglais |
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Date de production,
écriture : |
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2004 |
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| Journal : |
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| Astronomy and Astrophysics (Astron. Astrophys.) |
| Publisher |
EDP Sciences |
| ISSN |
0004-6361 (eISSN : 1432-0756) |
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| Date de publication : |
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2004 |
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| Volume : |
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422 |
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| Page, identifiant, ... : |
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841 |
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| Commentaire : |
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Accepted for publication in A&A - 25 Pages, 16 color figures, A&A Latex macro |
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