Graduation Semester and Year
Summer 2024
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Physics and Applied Physics
Department
Physics
First Advisor
Amir Shahmoradi
Second Advisor
Qiming Zhang
Third Advisor
Sangwook Park
Fourth Advisor
Manfred Cuntz
Fifth Advisor
Nevin Weinberg
Abstract
Gamma-ray bursts (GRBs) are the most energetic stellar explosions that have been observed in the universe. Due to their high energy and the collimated nature of the burst, they can be detected at cosmological distances. In addition to the prompt gamma-ray emission, an afterglow is usually detected at longer wavelengths, which can allow for a redshift calculation and localization of the host galaxy. Understanding GRBs is not only critical for determining the physics driving their progenitors, but for probing the high-redshift cosmos.
The space-based satellites that detect GRBs have complex triggering mechanisms, and accounting for their limitations (e.g., detection thresholds) is vital for drawing inferences from the data that they collect. Likewise, the statistical methods employed to analyze the data should be very carefully considered, so as to not unintentionally affect the conclusions drawn from the data.
In this dissertation, I present two studies that reconsider conclusions drawn from GRB datasets. The first study is a reanalysis of several recent studies that concluded there is a correlation between the luminosity/energetics of long GRBs (LGRBs) and their redshift. We demonstrate that the inferred correlations are likely significantly affected by an underestimation of the detection threshold. In the second study, the use of an apparent plateau in the duration distribution of LGRBs as evidence for the collapsar model is reexamined. We demonstrate that multiple aspects of the statistical properties of the dataset and methodologies used provide opportunity for the generation of a plateau that has no physical origin. Collectively, these studies aim to enhance the reliability of GRB studies by identifying and addressing the roles of bias and sample incompleteness.
Keywords
Gamma-ray burst, Supernova, Collapsar
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Bryant, Christopher M., "Investigating the Role of Bias and Sample Incompleteness in Gamma-ray Burst Studies" (2024). Physics Dissertations. 112.
https://mavmatrix.uta.edu/physics_dissertations/112