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Counts of galaxies in a merger modelA model for the photometric evolution of galaxies has been developed and has been applied to the problem of galaxy counts. The integrated colors of galaxies are calculated using the most recently computed evolutionary tracks from Maeder and collaborators complemented with evolutionary tracks derived by other authors. The asymptotic giant branch lifetime is left as a free parameter. A series of cosmological models using different values of the cosmological constant, lambda(sub 0), and the density parameter, omega(sub 0), have been computed. The universality hypothesis of the luminosity function of galaxies has been abandoned. The influence of galaxy merging on the counts has been considered in a simple manner by assuming that the number of strongly interacting galaxies in a comoving volume increases with redshift as a power law given by (1 + z)(exp 3.8). Taking a Schechter parametrization for the luminosity function of the different types of galaxies, we are able to reproduce the observations reasonably well. We have also considered models with a Gaussian distribution for the luminosity function of the brighter galaxies that provide a poorer fit to the observations. It is shown that galaxy count data are not yet able to make unambiguous cosmological statements since evolutionary assumptions are critical. In particular, an omega(sub 0) = 1, lambda(sub 0) = 0 cosmology is shown to be consistent with the data.
Document ID
19950034836
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Colin, P.
(Universidad Nacional Autonoma de Mexico Mexico)
Schramm, D. N.
(University of Chicago, Chicago, IL United States)
Peimbert, M.
(Universidad Nacional Autonoma de Mexico Mexico)
Date Acquired
August 16, 2013
Publication Date
May 10, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 426
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A66435
Distribution Limits
Public
Copyright
Other

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