1997/10/31 by V. Avila-Reese, Vladimir Avila‐Reese, C. Firmani +1 · 5 citations
Physics and Astronomy · #Astronomy #Astrophysics #Baryon #Cosmology and Gravitation Theories #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitation #Gravitational potential #Halo #Observable #Physics #Quantum mechanics #Scientific Research and Discoveries #Spectral density #Statistics #Structure formation #astro-ph
paper · pdf · doi:10.1086/306136
published as Astrophys.J.505:37,1998 · 31 pages, 7 ps figures. Accepted in ApJ. Minor corrections suggested by the referee
arxiv created 1998/04/22 · openalex publication_date 1998/09/20 · arxiv updated 2010/04/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We use a semianalytical approach and the standard σ 8 = 1 cold dark matter (SCDM) cosmological model to study the gravitational collapse and virialization, the structure, and the global and statistical properties of isolated dark matter galactic halos that emerge from primordial Gaussian fluctuations. First, from the statistical properties of the primordial density fluctuation field, the possible mass aggregation histories (MAHs) are generated. Second, these histories are used as the initial conditions of the gravitational collapse. To calculate the structure of the virialized systems, we have generalized the secondary infall model to allow arbitrary MAHs and internal thermal motions. The average halo density profiles we obtained agree with the profile derived as a fitting formula to results of N -body cosmological simulations by Navarro, Frenk, & White. The comparison of the density profiles with the observational data is discussed, and some possible solutions to the disagreement found in the inner regions are proposed. The results of our approach, after considering the gravitational dragging of the baryon matter that forms a central disk in centrifugal equilibrium, show that the empirical Tully-Fisher (TF) relation and its scatter can be explained through the initial cosmological conditions, at least for the isolated systems. The σ 8 = 1 SCDM model produces galaxies with high velocities when compared with observations, but when the SCDM power spectrum is normalized to σ 8 = 0.57, an excellent agreement with the observable TF relation is found, suggesting that this relation is the natural extension to galactic scales of the observed galaxy distribution power spectrum. The theoretical TF scatter is close to the measured one. The slope of the TF relation is practically invariant with respect to the spin parameter λ.