Abstract
view Abstract Citations (25) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Evolution of the Intergalactic Medium in a Cold Dark Matter--dominated Universe Chiang, Wei-Hwan ; Ryu, Dongsu ; Vishniac, Ethan T. Abstract We study the evolution of the intergalactic medium (IGM) in a cold dark matter-dominated universe. The dark matter is approximated as a pressureless ideal fluid. The IGM is approximated as an ordinary fluid. Several three-dimensional numerical simulations are performed to follow the evolution of the model universe from z ~ 100 to the present time. Galaxies are assumed to form from z = 10 to z = 1 at the highest density peaks. This leads to a burst of galaxy formation. They are subsequently assumed to release energy back into the IGM over a period of 10^8^ yr. The IGM is allowed to cool by Compton and radiative cooling. The model simulates a comoving volume of (9.6h^-1^)^3^ Mpc^3^ in current units on a grid of 32^3^ cells for h = 1 and h = 0.5. The major results are the following: (1) The growth of the root mean square density fluctuations in the IGM is greatly reduced during the period of heating, but it picks up at late times as gravity dominates again. (2) The density contour plots show large connected structure in the IGM. (3) The power spectrum for the IGM on smaller scales grows slower than the power spectrum of the dark matter. The slope of the two-point correlation function for the IGM is similar to that of the observed galaxy-galaxy correlation function between separations 1h^-1^ Mpc < r < 3h^-1^ Mpc. (4) The amount of gas with temperatures below 10^4^ K is negligible, that between 10^4^ and 10^5^ K is ~ 10%-20%, that between 10^5^ and 10^6^ K is >= 40%, and that above 10^6^ K is ~ 40%. The fraction of neutral hydrogen is very small. (5) The variation in pressure is ~10 times that in the temperature, suggesting no pressure equilibrium. Pressure is generally higher in regions of higher densities. (6) Optically thin lines computed show a variety of profiles. (7) The IGM has peculiar velocities of ~150 km s^-1^. The possible relevance of the model results to the forest of the Lyα absorption lines observed in quasars is discussed. Publication: The Astrophysical Journal Pub Date: April 1989 DOI: 10.1086/167321 Bibcode: 1989ApJ...339..603C Keywords: Computational Astrophysics; Dark Matter; Evolution (Development); Galaxies; Intergalactic Media; Universe; Absorption Spectra; Density Distribution; Galactic Evolution; Ideal Fluids; Lyman Alpha Radiation; Power Spectra; Astrophysics; COSMOLOGY; DARK MATTER; GALAXIES: INTERGALACTIC MEDIUM full text sources ADS |
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