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Astron. Astrophys. 317, 43-53 (1997)

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Galaxy evolution at low redshift?

I. Optical counts *

E. Bertin 1, 2 and M. Dennefeld 1, 3

1 Institut d'Astrophysique de Paris, 98bis Boulevard Arago, F-75014 Paris, France
2 European Southern Observatory, Casilla 19001, Santiago 19, Chile
3 Université Pierre & Marie Curie, 4, place Jussieu, F-75005 Paris, France

Received 22 December 1995 / Accepted 9 May 1996


We present bright galaxy number counts in the blue ( [FORMULA] ) and red ( [FORMULA] ) passbands, performed over 145 sq. degrees, both in the northern and southern galactic hemispheres. The work was conducted on Schmidt plates digitized with the MAMA machine, and individually calibrated using an adequate number of CCD sequences. We find a relatively large density of bright galaxies implying a "high" normalization of the local luminosity function. Our counts and colour distributions exhibit no large departure from what standard no-evolution models predict to magnitudes [FORMULA], removing the need for evolution of the non-dwarf galaxy population in the optical, out to [FORMULA]. This result disagrees with that of Maddox et al. (1990) on the APM catalog. We show that the APM and similar catalogs may be affected by a systematic magnitude scale error which would explain this discrepancy.

Key words: galaxies: evolution — galaxies: fundamental parameters — galaxies: luminosity function — galaxies: photometry — galaxies: statistics

* Based in part on observations made at the CERGA Schmidt Telescope (Observatoire de la côte d'Azur, France), at Observatoire de Haute-Provence (France) and at the European Southern Observatory (La Silla, Chile). ESO red survey, SERC blue survey and CERGA plates were digitized with MAMA (Machine Automatique à Mesurer pour l'Astronomie) which is developed and operated by INSU/CNRS.

Send offprint requests to: E. Bertin (bertin@iap.fr)


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© European Southern Observatory (ESO) 1997