Abstract
view Abstract Citations (24) References (49) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS N-Body Experiments with Gas in a Cosmological Model Carlberg, R. G. Abstract The formation of galaxies and their clustering is studied with an N-body experiment altered to include gas along with collisionless dark matter. The gas is isothermal, the simplest equation of state that dissipates energy under compression. The gas resists only shallow potential wells, that is, it has a "minimal" physical biasing for galaxy formation. The background cosmology has a local {OMEGA} > 1 and the particles are perturbed with a spectrum of waves having P(k) proportional to k^-1^. About one-fourth of the particles form into galaxies, originating in "1 σ" peaks, where σ is the amplitude of density fluctuations on the mass scale of galaxies, although there is a large dispersion of overdensities. The expected correlation between initial overdensity and the clustering environment of the galaxy clearly emerges, the highest peaks tending to become galaxies in the core of the cluster. Galaxies completely avoid the initially underdense regions. The autocorrelation function of the galaxies is generally a factor of 2-3 times stronger than that of the dark matter. The most massive galaxies form from 2 and more σ peaks, making their autocorrelation 2-4 times higher than that of all galaxies. In this {OMEGA} > 1 model all the galaxies eventually come together to form a stable group of 21 galaxies, corresponding closely to a poor cD cluster. The galaxies orbit in a dark matter background having 1000 times the mass of a typical galaxy, where the residual dynamical friction is defeated by continuing infall. The virial mass provides a reliable indication of the mass within the orbits of the galaxies. Global mass estimators are vexed by the absence of galaxies in low-density regions, underestimating the mass present by a factor of 2-10. The main conclusion is that this relatively conservative gas model provides a physical justification for significant "biasing" in the sites of galaxy formation. Publication: The Astrophysical Journal Pub Date: January 1988 DOI: 10.1086/165926 Bibcode: 1988ApJ...324..664C Keywords: Astronomical Models; Cosmology; Dark Matter; Galactic Clusters; Many Body Problem; Autocorrelation; Galactic Evolution; Galactic Structure; Star Formation; Astrophysics; COSMOLOGY; GALAXIES: CLUSTERING; GALAXIES: FORMATION full text sources ADS |
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