Cosmological constraints from standardized non-CMB observations

dc.contributor.authorCao, Shulei
dc.date.accessioned2023-04-11T19:02:26Z
dc.date.available2023-04-11T19:02:26Z
dc.date.graduationmonthMay
dc.date.issued2023
dc.description.abstractThe current expansion of the Universe has been observed to be accelerating, and the widely accepted spatially-flat concordance model of general relativistic cosmology attributes this phenomenon to a constant dark energy, a cosmological constant, which is measured to comprise about 70% of the total energy budget of the current Universe. However, observational discrepancies and theoretical puzzles have raised questions about this model, suggesting that alternative cosmological models with non-zero spatial curvature and/or dark energy dynamics might provide better explanations. To explore these possibilities, we have conducted a series of studies using standardized, lower-redshift observations to constrain six different cosmological models with varying degrees of flatness and dark energy dynamics. Through comparing these observations with theoretical predictions, we aim to deepen our understanding of the evolution of the Universe and shed new light on its mysteries. Our data provide consistent cosmological constraints across all six models, with some suggesting the possibility of mild dark energy dynamics and slight spatial curvature. However, these joint constraints do not rule out the possibility of dark energy being a cosmological constant and the spatial hypersurfaces being flat. Overall, our findings contribute to the ongoing efforts to refine our understanding of the Universe and its properties, and suggest that multiple cosmological models remain viable. In addition, our research demonstrates that certain types of astronomical observations, such as gamma ray bursts and reverberation-mapped quasar measurements, can be standardized and utilized in cosmology. This allows us to gain valuable insights into the properties of the Universe and its evolution by using these observations as distance indicators. By using these new standardized observations to constrain our cosmological models, we can improve our understanding of the nature of dark energy and other fundamental components of the Universe.
dc.description.advisorBharat Ratra
dc.description.degreeDoctor of Philosophy
dc.description.departmentDepartment of Physics
dc.description.levelDoctoral
dc.description.sponsorshipDepartment of Energy
dc.identifier.urihttps://hdl.handle.net/2097/42980
dc.language.isoen_US
dc.publisherKansas State University
dc.rights© the author. This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectCosmological parameters
dc.subjectCosmology observations
dc.subjectDark energy
dc.subjectQuasars emission lines
dc.subjectGamma-ray bursts
dc.titleCosmological constraints from standardized non-CMB observations
dc.typeDissertation

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
ShuleiCao2023.pdf
Size:
192.89 MB
Format:
Adobe Portable Document Format
Description:

License bundle

Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.6 KB
Format:
Item-specific license agreed upon to submission
Description: