Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 1995
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1995apj...450....1a&link_type=abstract
Astrophysical Journal v.450, p.1
Astronomy and Astrophysics
Astronomy
14
Cosmology: Large-Scale Structure Of Universe, Cosmology: Theory, Galaxies: Formation, Hydrodynamics, Methods: Numerical, Videotapes
Scientific paper
Two-dimensional numerical simulations of cosmological sheets are carried out to investigate nonlinear hydrodynamical effects on the formation of structures such as protogalaxies in the universe. We follow the motion of both baryonic and dark matter in a postrecombination Friedmann model universe with Ω0 = 1, Ωb = 0.1, and H0 = 75 km s-1 Mpc-1 at scales (≤ 10 Mpc) much smaller than the horizon size. We use a nonuniformly gridded code, composed of the Eulerian hydrodynamic solver ZEUS-2D modified for cosmology and a two-dimensional particle-mesh algorithm, to provide adequate resolution throughout the sheet structures. Our simulations allow us to examine in detail the role that nonlinear gravitational, cooling, and thin- shell instabilities play in the fragmentation of cosmological sheets. We compute characteristic fragmentation time and length scales for a variety of initial data and symmetries across the midplane. We find that although the fragmentation time is dependent on the power in the fluctuation spectrum, the average size of the protogalactic objects which form by the end of the fragmentation process (z ≳ 2.4) is similar in all cases studied, ranging from 8 to 13 kpc in the plane of collapse with masses of the order of a few times 108 Msun for both the baryonic and the dark matter. We also find that in relaxing reflection symmetry across the midplane, a thin shell instability acts as early times to excite the bending modes of the cold layer at scales set by kL ˜ 0.1, where k is the transverse wavenumber and L is the pancake thickness, significantly increasing the turbulence and local vorticity of the pancake.
Anninos Peter
Anninos Wenbo Y.
Norman Michael L.
No associations
LandOfFree
Nonlinear Hydrodynamics of Cosmological Sheets. II. Fragmentation and the Gravitational, Cooling, and Thin-Shell Instabilities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Nonlinear Hydrodynamics of Cosmological Sheets. II. Fragmentation and the Gravitational, Cooling, and Thin-Shell Instabilities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nonlinear Hydrodynamics of Cosmological Sheets. II. Fragmentation and the Gravitational, Cooling, and Thin-Shell Instabilities will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-823917