SearcharxivSearch

arXiv · astro-ph/9903210

A Database of COBE-Normalized CDM Simulations (Abbreviated Version)

Abstract

We have simulated the formation and evolution of large-scale structure in the universe, for 68 different COBE-normalized cosmological models. For each cosmological model, we have performed between 1 and 3 simulations, for a total of 160 simulations. This constitutes the largest database of cosmological simulations ever assembled, and the largest cosmological parameter space ever covered by such simulations. We are making this database available to the astronomical community. We provide instructions for accessing the database and for converting the data from computational units to physical units. The database includes Tilted Cold Dark Matter (TCDM) models, Tilted Open Cold Dark Matter (TOCDM) models, and Tilted Lambda Cold Dark Matter (TLCDM) models. (For several simulations, the primordial exponent n of the power spectrum is near unity, hence these simulations can be considered as "untilted.") The simulations cover a 4-dimensional cosmological parameter phase space, the parameters being the present density parameter Omega_0, cosmological constant lambda_0, and Hubble constant H_0, and the rms density fluctuation sigma_8 at scale 8/h Mpc. All simulations were performed using a P3M algorithm with 64^3 particles on a 128^3 mesh, in a cubic volume of comoving size 128 Mpc. Each simulation starts at a redshift of 24, and is carried up to the present. More simulations will be added to the database in the future.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Hugo Martel, Richard Matzner. 1999-03-13. A Database of COBE-Normalized CDM Simulations (Abbreviated Version). https://arxiv.org/abs/astro-ph/9903210

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Deformation procedure for scalar fields in cosmology

This work offers an extension of the deformation procedure introduced in field theory to the case of standard cosmology in the presence of real scalar field in flat space-time. The procedure is shown to work for many models, which give rise to several different cosmic scenarios, evolving under the presence of first-order differential equations which solve the corresponding equations of motion very appropriately.

astro-ph

Dark Energy is the Cosmological Quantum Vacuum Energy of Light Particles-The Axion and the Lightest Neutrino

We uncover the general mechanism producing the dark energy(DE). This is only based on well known quantum physics and cosmology. We show that the observed DE originates from the cosmological quantum vacuum of light particles which provides a continuous energy distribution able to reproduce the data. Bosons give positive contributions to the DE while fermions yield negative contributions. As usual in field theory, ultraviolet divergences are subtracted from the physical quantities. The subtractions respect the symmetries of the theory and we normalize the physical quantities to be zero for the Minkowski vacuum. The resulting finite contributions to the energy density and the pressure from the quantum vacuum grow as log a(t) where a(t) is the scale factor, while the particle contributions dilute as 1/a^3(t), as it must be for massive particles. The DE equation of state P = w(z)H turns to be w(z)<-1 with w(z) asymptotically reaching the value -1 from below.A scalar particle can produce the observed DE through its quantum cosmological vacuum provided:(i)its mass is of the order of 10^{-3} eV = 1 meV,(ii) it is very weakly coupled and (iii) it is stable on the time scale of the age of the universe. The axion vacuum thus appears as a natural candidate. The neutrino vacuum (especially the lightest mass eigenstate) can give negative contributions to the DE. We find that w(z=0) is slightly below -1 by an amount ranging from [-1.5 10^{-3}] to [-8 10^{-3}] and we predict the axion mass to be in the range between 4 and 5 meV. We find that the universe will expand in the future faster than the de Sitter universe, as an exponential in the square of the cosmic time. DE arises from the quantum vacua of light particles in FRW cosmological space time in an analogous way to the Casimir effect in Minkowski spacetime with non trivial boundaries.

astro-ph