Pure luminosity evolution hypothesis for QSOs: from luminosity functions to simulated catalogues.
Abstract
This paper describes the construction of realistic extragalactic Monte-Carlo catalogues, aimed at comparing the behaviour of cosmological tests as a function of various parameters. An input luminosity function is required to simulate QSO catalogues: it is derived from data through an arbitrary choice of cosmological and evolutionary models. A due attention must be paid to the computation of individual maximum volumes in complete (magnitude- and redshift-limited) samples. Details of this computation are examined for the case of strong luminosity evolution. The values of the evolution parameter are derived for various cosmologies, corresponding to <V/V_max_>=1/2 in the sample of 400 Ultra-Violet Excess (UVX) QSOs Boyle (1990MNRAS.243....1B). The various luminosity functions are compared, both for the whole sample and in redshift bins. A characteristic evolution time is defined and computed, depending strongly on the cosmology, but practically constant when expressed in terms of the age of the universe. Algorithms are given for producing catalogues based on the simple hypothesis that the objects are uniformly distributed in volume but suffer pure luminosity evolution. The only input based on real data is the luminosity function, but this requires neither a redshift nor an apparent magnitude histogram. Simulated redshift and absolute magnitude histograms are compared to real data.
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- December 1996
- Bibcode:
- 1996A&A...316...19M
- Keywords:
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- COSMOLOGY;
- QUASARS;
- NUMERICAL SIMULATIONS