Abstract
High-frequency-peaked BL Lacertae blazars (HBLs) dominate the extragalactic sky at energies above 0.1 TeV, and have been extensively studied in TeV gamma-ray, X-ray, and many other energy bands. Despite this, many questions still remain about the properties of this class of sources and the mechanisms used to accelerate relativistic particles in their powerful jets. HBLs are often observed when their emission is known to be in a flaring state, which biases our understanding of their overall properties and duty cycles. The VERITAS observatory has recently concluded a long-term observing campaign of 36 X-ray-selected blazars to produce the first unbiased survey of HBLs at TeV gamma-ray energies, which is a crucial step towards deriving a TeV luminosity function and modeling the evolution of the HBL population across cosmic time. In this dissertation I present the full results of the VERITAS unbiased HBL survey, including the first logN-logS distribution of TeV fluxes from HBLs, a measure of the number density of sources as a function of gamma-ray flux. However, while broad surveys like this one allow us to constrain properties of the whole source population, it is more detailed studies of individual nearby bright objects that allow us to study blazar jet dynamics and the physical processes involved in particle acceleration. For that reason, this dissertation also presents the results of a focused joint observing campaign of one specific nearby HBL, Markarian 421, which combines gamma-ray observations from VERITAS with simultaneous X-ray polarization measurements from IXPE. The combined results provide information about the physical properties of the emission region where both the X-rays and gamma rays are produced, and help constrain the possible particle acceleration mechanisms in the blazar jet. Through these two projects we study high-frequency-peaked BL Lac objects as both individuals and as a population, aiming to advance our understanding of the nature of these blazar sources and the physical processes which govern them.
Committee Chair
Manel Errando
Committee Members
Michael Nowak; Reshmi Mukherjee; Saori Pastore; Yajie Yuan
Degree
Doctor of Philosophy (PhD)
Author's Department
Physics
Document Type
Dissertation
Date of Award
4-27-2026
Language
English (en)
DOI
https://doi.org/10.7936/qpd1-v698
Author's ORCID
https://orcid.org/0000-0002-5104-5263
Recommended Citation
Rabinowitz, Pazit Liviya, "X-Ray Polarization and Gamma-Ray Studies of High-Frequency-Peaked BL Lacertae Objects" (2026). Arts & Sciences Graduate Student Theses and Dissertations. 3813.
The definitive version is available at https://doi.org/10.7936/qpd1-v698