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Probing the new cosmology

Zentner, Andrew Ronald
http://rave.ohiolink.edu/etdc/view?acc_num=osu1054160085

Abstract Details

2003, Doctor of Philosophy, Ohio State University, Physics.
Improvements in obserational techniques have transformed cosmology into a field inundated with ever-expanding, high-quality data sets and driven cosmology toward a standard model where the classic cosmological parameters are accurately measured. I briefly discuss some of the methods used to determine cosmological parameters, particularly primordial nucleosynthesis, the magnitude-redshift relation of supernovae, and cosmic microwave background anisotropy. I demonstrate how cosmological data can be used to complement particle physics and constrain extensions to the Standard Model. Specifically, I present bounds on light particle species and the properties of unstable, weakly-interacting, massive particles. Despite the myriad successes of the emerging cosmological model, unanswered questions linger. Numerical simulations of structure formation predict galactic central densities that are considerably higher than observed. They also reveal hundreds of satellites orbiting Milky Way-like galaxies while the Milky Way has only eleven known satellites within 300kpc. I explore the possibility that these conundrums may have a common remedy in the form of the power spectrum of initial density fluctuations that seed structure growth. To address the substructure issue, I develop a semi-analytic method that suffers from no inherent resolution limits and can therefore be used to complement numerical simulations. I find that tilted primordial power spectra and spectra with running tilts provide for an intriguing possibility. In these models, the amplitude of initial fluctuations can be normalized against the cosmic microwave background measurements on large scales. Yet, the reduction in small-scale power brings galactic central densities down to acceptable levels and allows for the Milky Way satellite population to be accounted for without invoking differential feedback mechanisms. Furthermore, substructure mass fractions are not significantly altered in these models so probes of substructure via gravitational lensing do not disfavor them. The primordial fluctuations are thought to be generated during an early epoch of inflation and one implication is that galaxy properties may convey information about inflation. I also address alternative proposals, such as warm dark matter and broken scale-invariant inflation, in light of lensing probes of substructure and find these models to be disfavored. I close with a few words on refining the model and alternative applications.
Terrence Walker (Advisor)
289 p.
Cosmology

Recommended Citations

Citations

  • Zentner, A. R. (2003). Probing the new cosmology [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1054160085

    APA Style (7th edition)

  • Zentner, Andrew. Probing the new cosmology. 2003. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1054160085.

    MLA Style (8th edition)

  • Zentner, Andrew. "Probing the new cosmology." Doctoral dissertation, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1054160085

    Chicago Manual of Style (17th edition)

osu1054160085
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© 2003, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.