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Halo Distribution Inside Cosmic Voids in the Excursion Set Theory

Ashuri Kisomi, Zeynab | 2024

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56945 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Baghram, Shant
  7. Abstract:
  8. The purpose of this research is to provide a model to explain the dependence of the galaxy distribution within voids on redshift and the density of the environment. The study of the formation of large-scale structures in the universe, as one of the most important observables in cosmology, is of great importance. Investigating the formation of these structures is possible by going beyond the linear regime and using theories such as the Press-Schechter and the excursion set. Also, by developing this type of approach, theories have been made possible to study the statistics of halos in environments such as voids, which can be useful for a better understanding of the formation and evolution of structures in the universe. In this research, we first test the excursion set theory with a moving barrier as a theory to explain the distribution of halos. To do so, we use a measurable quantity called the galaxy luminosity function. Then, we study the dependence of the galaxy luminosity function on redshift and environmental density contrast. Due to advantages such as the lack of mergers and collisions in voids, the study of galaxies within them can be more useful than galaxies within crowded and populous environments. In the continuation of the research, we present a theoretical relationship to explain this dependence. The proposed relations are tested with two data sets 2dFGRS and GAMA. We use the chi-squared test (χ2) to test the theory with the data. The results show that these relationships are superior to the previously proposed formulas. So that the quantity χ2 is reduced by one order of magnitude
  9. Keywords:
  10. Excursion Set Theory ; Universe Large-Scale Structure ; Dark Matter Halo ; Voids Galaxies ; Galaxy Luminosity Function

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