Fire From the Dark Side: Dark Matter Annihilation Feedback Across Cosmic Time
Feb 28, 2019132 pages
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Thesis: PhD - ,
- Sydney U.
- Published: Feb 28, 2019
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Abstract: (Sydney U.)
This cold dark matter is one of the pillars of the standard model of cosmology and galaxy formation. However, modern simulations of the Universe based on dark matter paradigms have investigated the growth of galaxies, and several apparent challenges to the current cosmological model have appeared. In addition, the scientific community has been unable to achieve a confirmed direct detection of any such dark matter.Dark matter annihilation is expected to be enhanced where dark matter densities are high, like the inner regions of dark matter halos. A consequence of the significant energy release into the gas of a galaxy is a change in the predicted properties of galaxies. Cooling gas accreting into the gravitational wells of dark matter halos forms galaxies and stars. Thus, this Dark Matter Annihilation Feedback (DMAF) energy has implications for the accretion of gas, star formation rates, and gas temperatures.We ran simulations which showed that DMAF leads to different mass growth rates of the most massive structures, possibly as a result of gas stalling at the outskirts of dark matter halos. Smaller dark matter structures like dwarfs and satellites are the most sensitive to DMAF due to their low gravitational binding energy. Even with DMAF, halos contain dark matter density profiles that continuously increase towards the centre; finding their net effect is to prevent a build-up of gas thus making DMAF a complement to the astrophysical solutions of the missing satellites problems. Modern simulations with model galaxy formations prescriptions show dwarf halos with masses of about M are on the cusp of forming galaxies because the heating and cooling rates are thought to be nearly equal. Hence these dwarf haloes are promising targets for future studies of DMAF.In conclusion, we have demonstrated that DMAF is a potentially significant ingredient in galaxy formation and thus may serve to increase our understanding of the dark matter paradigm.- dark matter
- cosmology
- astroparticles
- dark matter: halo
- dark matter: annihilation
- galaxy: formation
- dark matter: density
- gas: accretion
- galaxy: model
- gas: temperature
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