Universe (Feb 2022)
Star and Black Hole Formation at High Redshift
Abstract
Evidence for dark matter (DM) was originally discovered in 1933 by Zwicky (Zwicky 1933, 1937), and has defied all explanations since then. The original discovery was based on the motions of galaxies in clusters of galaxies. The MicroWave Back Ground (MWBG) observations by the Planck mission and other satellites give definitive numbers. Galaxy correlations give results down to small galaxies, which match theoretical expectations. Here we focus on a few interesting aspects, that may allow to determine the nature of dark matter: (1) Ultra Faint Dwarf (UFD) galaxies, that represent the oldest galaxies known. UFDs are almost devoid of baryonic matter. (2) Calculations show that there can be super-sonic flow of baryonic matter. It follows that there are ubiquitous shockwaves; commonly oblique they generate vorticity. (3) Early virialized clumps, mini-halos, have a density that is consistent with the density implied by Super Massive Black Holes (SMBHs) today, if we assume that SMBHs grow by merging, akin to the Press & Schechter (1974) picture for galaxies. This implies that the oldest SMBHs observed today give powerful constraints on the very early phases.
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