Other Astrophysics and Astronomy Commons^™

Study Of Particle Accelerators In The Universe With The Hawc Observatory, Rishi Babu

Dissertations, Master's Theses and Master's Reports

HESS J1809-193 is an unidentified TeV source discovered in 2007 by the High Energy Stereoscopic System(H.E.S.S.) Collaboration. The emission originates in a region that is rich in cosmic-ray accelerators, including several supernova remnants and pulsars, including SNR G11.1+0.1, SNR G11.0-0.0, and the young radio pulsar PSR J1809-1917. Originally classified as a pulsar wind nebula candidate, recent studies show the peak of the TeV region overlapping with a system of molecular clouds and revising the original classification for other scenarios, including a pure hadronic scenario. This dissertation presents the morphological and spectral study of HESS J1809-193 using 2139 days of data …

A Search For Compact Object Dark Matter In The Universe Utilizing Gravitational Millilensing Of Gamma-Ray Bursts, Oindabi Mukherjee

Dissertations, Master's Theses and Master's Reports

In this dissertation, I explore the existence of Compact Object (CO) Dark Matter (DM), examining its predicted millilensing impact on the light curves of Gamma-Ray Bursts (GRBs). The hypothesis under investigation is that if CO DM exists, it will act as a gravitational lens, influencing light emanating from GRBs and creating a measurable gravitational echo. The detection of this echo is conditional on several factors, including the spatial alignment of the observer, lens, and source and the mass of the CO DM.

Recent studies have reported the potential detection of millilensing in several GRBs, including GRB 950830, GRB 081122A, GRB …

Tracing The Most Powerful Galactic Cosmic-Ray Accelerators With The Hawc Observatory, Dezhi Huang

Dissertations, Master's Theses and Master's Reports

Since Victor Hess's groundbreaking detection of cosmic rays in the Earth's atmosphere in 1912, the origins of these charged particles have remained an enduring mystery. Recent studies suggest that these cosmic rays are accelerated beyond Peta electronvolts by powerful astrophysical sources within our own galaxy. While the cosmic rays themselves are being deflected in all directions by magnetic fields, the gamma rays produced by them, being electrically neutral, travel to the observer in a straight line. They carry crucial information, allowing us to trace cosmic-ray accelerators within our galaxy. The High Altitude Water Chrenkov (HAWC) Observatory, located on the slopes …

Searching For Anomalous Extensive Air Showers Using The Pierre Auger Observatory Fluorescence Detector, Andrew Puyleart

Dissertations, Master's Theses and Master's Reports

Anomalous extensive air showers have yet to be detected by cosmic ray observatories. Fluorescence detectors provide a way to view the air showers created by cosmic rays with primary energies reaching up to hundreds of EeV . The resulting air showers produced by these highly energetic collisions can contain features that deviate from average air showers. Detection of these anomalous events may provide information into unknown regions of particle physics, and place constraints on cross-sectional interaction lengths of protons. In this dissertation, I propose measurements of extensive air shower profiles that are used in a machine learning pipeline to distinguish …

Preliminary Studies Of Background Rejection Capabilities For The Southern Wide−Field Gamma−Ray Observatory, Sonali Mohan

Dissertations, Master's Theses and Master's Reports

The Southern Wide-field Gamma-ray Observatory (SWGO), is a next-generation
gamma-ray observatory to be constructed in the Southern Hemisphere that will com-
plement current and future instruments by providing a wide-field coverage of a large
portion of the southern sky and a better sensitivity to the 100 GeVs to few PeVs
photon band to understand extreme astrophysical phenomena throughout the uni-
verse. Air shower events initiated by gamma rays will be recorded by the detector
and reconstructed to extract shower properties. The challenge for air-shower arrays
in the observation of gamma-ray sources is the large background of hadronic cos-
mic rays. …

A Combined Spectral And Energy Morphology Analysis Of Gamma Ray Source Hawc J2031+415 In The Cygnus Constellation, Ian Herzog

Dissertations, Master's Theses and Master's Reports

HAWC J2031+415 is a probable pulsar wind nebula (PWN) located in the Cygnus Cocoon region near a complex OB star cluster. First observed by the High-Energy-Gamma-Ray Astronomy (HEGRA) observatory in the TeV energy regime, the source had no apparent counterpart in lower energy ranges. Previous work using 1343 days of data from the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory has determined that three sources are present in the Region of Interest (ROI): HAWC J2031+415, HAWC J2030+409 (also known as the Cocoon), and 3HWC J2020+403 (associated with the Gamma Cygni supernova remnant) \cite{Ian_01, Binita_01}.

In this work, I use the newest …

Toward Deep Learning Emulators For Modeling The Large-Scale Structure Of The Universe, Neerav Kaushal

Dissertations, Master's Theses and Master's Reports

Multi-billion dollar cosmological surveys are being conducted almost every decade in today’s era of precision cosmology. These surveys scan vast swaths of sky and generate tons of observational data. In order to extract meaningful information from this data and test these observations against theory, rigorous theoretical predictions are needed. In the absence of an analytic method, cosmological simulations become the most widely used tool to provide these predictions in order to test against the observations. They can be used to study covariance matrices, generate mock galaxy catalogs and provide ready-to-use snapshots for detailed redshift analyses. But cosmological simulations of matter …

Cosmic-Ray Acceleration In The Cygnus Ob2 Stellar Association, Binita Hona

Dissertations, Master's Theses and Master's Reports

The Cygnus region of our Galaxy consists of an active star forming region and a wealth of various astrophysical sources such as pulsar wind nebulae (PWN), supernova remnants (SNRs), and massive star clusters. Massive stellar clusters and associations have been postulated as possible sources of cosmic rays (CRs) in our Galaxy. One example of a gamma-ray source associated with a stellar association lies in the Cygnus region known as the "Cygnus Cocoon". It is an extended region of gamma-ray emission in the Cygnus X region and attributed to a possible superbubble with freshly accelerated CRs which are hypothesized to produce …

Understanding The Very High Energy Γ-Ray Emission From A Fast Spinning Neutron Star Environment, Chad A. Brisbois

Dissertations, Master's Theses and Master's Reports

Pulsars, and their associated pulsar wind nebulae, are factories producing high energy electrons and positrons in our galaxy. The Dragonfly nebula is a Vela-like pulsar wind nebula in the Cygnus region powered by the spin down of PSR J2021+3651. The TeV γ-ray source 2HWC J2019+367 was originally discovered in 2007 by the Milagro Observatory and has been associated with this pulsar. This dissertation presents the first detailed morphological and spectral study of the TeV emission up to the highest photon energies of 2HWC J2019+367. This analysis has identified two sources, the extended source HAWC J2019+368 and the point source HAWC …

Reply To Commentary By R Duggleby (2019), Edward J. Steele, Shirwan Al-Mufti, Kenneth Augustyn, Rohana Chandrajith, John P. Coghlan, S. G. Coulson, Et Al.

Michigan Tech Publications, Part 1

No abstract provided.

Evaluating The Effectiveness Of Current Atmospheric Refraction Models In Predicting Sunrise And Sunset Times, Teresa Wilson

Dissertations, Master's Theses and Master's Reports

The standard value for atmospheric refraction on the horizon of 34', used in all publicly available sunrise and sunset calculators, is found to be inadequate. The assumptions behind atmospheric models that predict this value fail to account for real meteorological conditions. The result is an uncertainty of one to five minutes in sunrise and sunset predictions at mid-latitudes (0° - 55° N/S). A sunrise/set calculator that interchanges the refraction component by varying the refraction model was developed. Two atmospheric refraction models of increasing complexity were tested along with the standard value. The predictions were compared with data sets of observed …

Effects Of Mass And Distance Uncertainties On Calculations Of Flux From Giant Molecular Clouds, Matt Coel

Dissertations, Master's Theses and Master's Reports

It is assumed that the distribution of the Milky Way cosmic rays, the cosmic ray ‘sea,’ is even throughout the Galaxy. This assumption can be tested by measuring gamma rays produced from cosmic ray interactions with Giant Molecular Clouds. The gamma ray flux depends on the mass and distance of a given molecular cloud as well as the cosmic ray flux in its vicinity. Thus a predicted gamma ray flux can be compared to actual flux data from a detector. Uncertainties from measuring the mass of and distance to the clouds are taken into account for this prediction. This report …