L. Vincoletto, F. Matteucci, F. Calura, L. Silva, G. Granato
The cosmic star formation rate (CSFR), is an important clue to investigate
the history of the assembly and evolution of galaxies. Here, we develop a
method to study the CSFR from a purely theoretical point of view. Starting from
detailed models of chemical evolution, we obtain the histories of star
formation of galaxies of different morphological types. These histories are
then used to determine the luminosity functions of the same galaxies by means
of a spectro-photometric code. We obtain the CSFR under different hypothesis.
First, we study the hypothesis of a pure luminosity evolution scenario, in
which all galaxies are supposed to form at the same redshift and then evolve
only in luminosity. Then we consider scenarios in which the number density or
the slope of the LFs are assumed to vary with redshift. After comparison with
available data we conclude that a pure luminosity evolution does not provide a
good fit to the data, especially at very high redshift, although many
uncertainties are still present in the data. On the other hand, a variation in
the number density of ellipticals and spirals as a function of redshift can
provide a better fit to the observed CSFR. We also explore cases of variable
slope of the LFs with redshift and variations of number density and slope at
the same time. We cannot find any of those cases which can improve the fit to
the data respect to the solely number density variation. Finally, we compute
the evolution of the average cosmic metallicity in galaxies with redshift.
View original:
http://arxiv.org/abs/1201.1751
No comments:
Post a Comment