Physical Sciences and Mathematics Commons^™

An Introduction To The Veritas Observatory, Alexander Biddle, Ian Kuhl, Jingze (Justin) Zhou, Avery Archer

Annual Student Research Poster Session

Located at the base of Mount Hopkins, Arizona, at an elevation of approximately 4200 feet, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a ground-based gamma ray observatory containing four Cherenkov telescopes designed to detect very high energy gamma rays with energies ranging from 100GeV to 10TeV using the Imaging Atmospheric Cherenkov Technique. In April 2007, VERITAS began successful operations with all four telescopes. As of today, over 15 years of data has been taken by the VERITAS array, stored in an archive of data, and used for a wide variety of research, publications, PhD theses, and conventions …

Analysis Of The Crab Nebula And Pulsar, Alexander Biddle, Ian Kuhl, Jingze (Justin) Zhou, Avery Archer

Annual Student Research Poster Session

Although the Crab Nebula is well understood, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) still regularly observes the Crab's highest energy emissions. These emissions are used to calibrate the telescopes, further, document the system, and investigate the validity of physical models. Our research this summer is geared to analyze data from 2018-2022 to add to an ongoing research project investigating the long term variability of the Crab Nebula’s emission.

Radio Pulsar Searching And Timing Follow-Up, Alexander Eli Mcewen

Theses and Dissertations

Pulsars provide some of the richest laboratories for studying the behavior of ultra-dense matter. As such, they have been utilized for decades to place stringent limits on gravitation and as probes of the material that fills our Galaxy. These tests benefit greatly from a catalog of pulsars that is as complete as possible, which in turn requires thorough searches of the Galaxy and precise timing of discoveries. These searches are informed by the continued characterization of the pulsar population, and so searching techniques develop in tandem with the analysis of their discoveries. Large scale pulsar surveys find pulsars; small scale …

Transform Based Approaches For The Detection Of Astrophysical Signals, Marwan Mahfud Alkhweldi

Graduate Theses, Dissertations, and Problem Reports

Development of new algorithms for the detection of isolated astrophysical pulses is of interest to radio astronomers. Both Fast Radio Bursts (FRBs) and several Rotating Radio Transients (RRATs) were detected through the application of a single pulse search algorithm. The conventional approach to detect astronomical pulses requires an exhaustive search for the correct dispersion measure. Its accelerated versions involve signal processing in Fourier transform space.

In this dissertation, we present several new transform-based approaches for the detection and analysis of astrophysical signals with the latest being the most effective and advanced of all. It is implemented in several steps. First, …

Identification And Classification Of Radio Pulsar Signals Using Machine Learning, Di Pang

Graduate Theses, Dissertations, and Problem Reports

Automated single-pulse search approaches are necessary as ever-increasing amount of observed data makes the manual inspection impractical. Detecting radio pulsars using single-pulse searches, however, is a challenging problem for machine learning because pul- sar signals often vary significantly in brightness, width, and shape and are only detected in a small fraction of observed data.

The research work presented in this dissertation is focused on development of ma- chine learning algorithms and approaches for single-pulse searches in the time domain. Specifically, (1) We developed a two-stage single-pulse search approach, named Single- Pulse Event Group IDentification (SPEGID), which automatically identifies and clas- …

A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan

Macalester Journal of Physics and Astronomy

We present observations from two separate methods for observing the Galactic Center in an attempt to characterize its pulsar and neutron star populations. A persistent puzzle of the past 20 years has been the lack of pulsar detections towards the Galactic Center, specifically within a few parsecs of the central supermassive black hole Sgr A*. This object is bright in the total intensity of its polarized emission, but is very weakly linearly polarized. We take advantage of these circumstances in an experimental search technique where we utilize the Faraday effect in an attempt to detect high rotation measure (RM) point …

Design And Modal Analysis Of An Ultra-Wideband Receiver For Green Bank Observatory, Alyssa Bulatek

Macalester Journal of Physics and Astronomy

The next generation of radio receivers for astronomy will be marked by tenfold improvements in sensitivity. These sensitive receivers will be useful for the detection of broadband fast radio bursts and other transients as well as the efficient discovery of radio recombination lines among many other scientific pursuits. One contribution to these improvements is an increase to decade receiver bandwidths. The Green Bank Observatory (GBO) is currently in the process of fabricating a new ultra-wideband (UWB; 0.7 to 4.2 GHz) receiver for the Green Bank Telescope (GBT). The UWB receiver will be used by the North American Nanohertz Observatory for …

Searching For Needles In The Cosmic Haystack, Thomas Ryan Devine

Graduate Theses, Dissertations, and Problem Reports

Searching for pulsar signals in radio astronomy data sets is a difficult task. The data sets are extremely large, approaching the petabyte scale, and are growing larger as instruments become more advanced. Big Data brings with it big challenges. Processing the data to identify candidate pulsar signals is computationally expensive and must utilize parallelism to be scalable. Labeling benchmarks for supervised classification is costly. To compound the problem, pulsar signals are very rare, e.g., only 0.05% of the instances in one data set represent pulsars. Furthermore, there are many different approaches to candidate classification with no consensus on a best …

Real-Time Rfi Mitigation In Radio Astronomy, Emily Ramey, Nick Joslyn, Richard Prestage, Michael Lam, Luke Hawkins, Tim Blattner, Mark Whitehead

Senior Honors Papers / Undergraduate Theses

As the use of wireless technology has increased around the world, Radio Frequency Interference (RFI) has become more and more of a problem for radio astronomers. Preventative measures exist to limit the presence of RFI, and programs exist to remove it from saved data, but the use of algorithms to detect and remove RFI as an observation is occurring is much less common. Such a method would be incredibly useful for observations in which the data must undergo several rounds of processing before being saved, as in pulsar timing studies. Strategies for real-time mitigation have been discussed and tested with …

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 …

A Multi-Frequency Study Of Arecibo Pulsars, Timothy Eugene Edward Olszanski

Graduate College Dissertations and Theses

Compact Objects (Neutron Stars) form in the last moments of a star's life, during the violent events known as supernovae. As the star's core fusion falters, matter undergoes a dramatic gravitational compression resulting in internal densities rivaling subatomic particles. Ever since their discovery in the mid-twentieth century, these highly magnetized and rapidly rotating balls of condensed matter have provided a bountiful playground for astronomers seeking out exotic physics.

Neutron Stars that emit electromagnetic radiation are seen by observers as Pulsars, named such for the pulse of intensity as the pulsar's radiation beam passes into our line of sight. These beams …

Shakespeare, A Supernova, And A Little Green Man Walk Into A Mathematics Classroom, Sheila Kirstin Miller

Journal of Humanistic Mathematics

Creativity amidst constraints is a hallmark of the STEM researcher. It is precisely what is required to see what has never been seen. It is also at the core of creative mathematics, more commonly called “research”. We in the 21^st century tell ourselves that science and story are separate enterprises. One goal of this article is to tell parts of the human story—featuring Shakespeare, Tycho Brahe, visiting stars, Little Green Men, and modern astrophysics—that might erode belief in that duality and illustrate why dissolving the artificial barriers between talents within individuals is to the benefit of ourselves, our students, …