Astrophysics and Astronomy Commons^™

Signal Yields And Detector Modeling In Xenon Time Projection Chambers, And Results Of An Effective Field Theory Dark Matter Search Using Lux Data, Gregory Ransford Carl Rischbieter

Legacy Theses & Dissertations (2009 - 2024)

The nature of dark matter continues to be one of the biggest remaining mysteries in physics. Astrophysical measurements indicate that dark matter makes up more than a quarter of the Universe's total energy density, and it is well-motivated that dark matter is comprised of Weakly Interacting Massive Particles (WIMPs). Direct detection techniques utilizing liquid and gaseous noble elements have become the primary method of probing the potential non-gravitational interactions between WIMPs and Standard Model matter, with the leading technology being the dual-phase Time Projection Chamber (TPC). The Large Underground Xenon (LUX) and its second-generation successor, LUX-ZEPLIN (LZ), are two xenon …

The Majorana Demonstrator Readout Electronics System, N. Abgrall, M. Amman, I. J. Arnquist, Frank Avignone Iii, A. S. Barabash, C. J. Barton, P. J. Barton, F. E. Bertrand, K. H. Bhimani, B. Bos, A. W. Bradley, T. H. Burritt, M. Busch, M. Buuck, T. S. Caldwell, Y-D. Chan, C. D. Christofferson, P.-H. Chu, M. L. Clark, R. J. Cooper, C. Cuesta, Et. Al.

Faculty Publications

The Majorana Demonstrator comprises two arrays of high-purity germanium detectors constructed to search for neutrinoless double-beta decay in 76Ge and other physics beyond the Standard Model. Its readout electronics were designed to have low electronic noise, and radioactive backgrounds were minimized by using low-mass components and low-radioactivity materials near the detectors. This paper provides a description of all components of the Majorana Demonstrator readout electronics, spanning the front-end electronics and internal cabling, back-end electronics, digitizer, and power supplies, along with the grounding scheme. The spectroscopic performance achieved with these readout electronics is also demonstrated.

Using Nasa's Tess Mission To Search For Extremely Low Mass White Dwarf Stars, Corinna Peña

Undergraduate Honors Thesis Collection

Extremely low-mass white dwarf stars (ELM) are white dwarf stars with a mass lower than 0.45 solar masses that could not have evolved through normal processes within the lifetime of our universe. Therefore, these objects can only be created through a common envelope phase or a stable Roche lobe overflow while in a binary. These objects have periods between a few minutes to a few hours, so they are very short lived which makes them very rare. My goal for this project was to find these ELM stars by using NASA's Transiting Exoplanet Survey Satellite (TESS) data. I analyzed this …

Electromagnetic Detectability Of Binary Supermassive Black Holes, Kaylee Grace

Honors Scholar Theses

Supermassive black hole (SMBH) binaries can be produced by galaxy mergers and are important sources of gravitational waves. Although several binary candidates have been identified in previous work, none have yet been fully confirmed. These pairs are difficult to detect, since single accreting SMBHs can have pseudo-periodic lightcurves due to stochastic noise that can mimic the signature of binary SMBHs. The aforementioned lightcurves are the detections we classify as ”false-positive.” The Vera Rubin Observatory (VRO) will be a powerful new tool for detecting binary SMBHs. We determine the false-positive binary detection rate for VRO by attempting to recover sinusoidal binary …

The Development Of A New All-In-One Allsky Camera And Radiometer System, Ashley Suzanne Hughes

Theses and Dissertations

We developed a new all-in-one camera and radiometer system for meteor surveillance. It proved successful during its first bolide event on 13 April 2021, as reported in the journal Meteoritics and Planetary Science, volume 57, number 3, pages 575-587. The event capture produced both video and radiometric data, and with the video data we were able to calculate a trajectory and orbit, and determine the fragmentation characteristics of the meteor as it traveled through the atmosphere.

Extreme-Contrast Ratio Imaging Of Bright Star Fields Using Charge-Injection Devices, Sailee Mangesh Sawant

Theses and Dissertations

The intrinsic nature of many astronomical sources, such as exoplanets, binary and multiple star systems, circumstellar disks, and active galactic nuclei and their host galaxies, introduces challenging requirements for observational instrumentation and techniques. In each case, we encounter situations where the light from bright sources hampers our abilities to detect surrounding fainter targets. To explore and study all features of such extreme-contrast ratio (ECR) scenes, we must perform observations at the maximum possible contrast ratios. However, direct imaging of fainter objects in the vicinity of bright sources imposes limitations on the type of contrast ratios achievable using ground- and spacebased …

Elevated Hot Gas And High-Mass X-Ray Binary Emission In Low-Metallicity Galaxies: Implications For Nebular Ionization And Intergalactic Medium Heating In The Early Universe, Bret D. Lehmer, Rafael T. Eufrasio, Antara Basu-Zych, Kristen Garofali, Woodrow Gilbertson, Andrei Mesinger, Mihoko Yukita

Space and Planetary Science Faculty Publications and Presentations

High-energy emission associated with star formation has been proposed as a significant source of interstellar medium (ISM) ionization in low-metallicity starbursts and an important contributor to the heating of the intergalactic medium (IGM) in the high-redshift (z ≳ 8) universe. Using Chandra observations of a sample of 30 galaxies at D ≈ 200–450 Mpc that have high specific star formation rates of 3–9 Gyr−1 and metallicities near Z ≈ 0.3Z⊙, we provide new measurements of the average 0.5–8 keV spectral shape and normalization per unit star formation rate (SFR). We model the sample-combined X-ray spectrum as a …

Exploring The Glow Of The Universe In Gamma-Rays And Hunting Distant Agn, Changam Meenakshi Rajagopal

All Dissertations

The entirety of the γ-ray radiation permeating our Universe is encoded in the extragalactic γ-ray background. This is a superposition of resolved sources, mostly powerful relativistic jets powered by supermassive black holes, i.e., blazars, and an unresolved isotropic component, aka, the diffuse isotropic gamma-ray background (IGRB). Studying the IGRB can help unveil its composition, as well as unearth multi-messenger relationships between the intensities of PeV neutrinos, ultra high energy cosmic rays (> 1018 eV), and sub-TeV γ-rays. The comparable energy budgets of these three phenomena (neutrinos, UHECR, and γ-rays) indicates a physical connection or a common source amongst them. On …

“Lasso The Moon? Is It Possible? What About Hack The Moon? Today’S International Framework For Activities On The Moon”, Diane M. Janosek, Armando Seay, Josa P. Natera

Military Cyber Affairs

The global interest in the moon and outer space continues to skyrocket. The current U.S. commercial investment in space is $350 billion annually, and it is expected to grow to $1 Trillion or more by 2040. The U.S. military investment in space defense and research likewise continues to grow, with the total investment amount remaining classified. With the frequent activity in space, as well as concerns about attacks to US space assets to and from space, the U.S, created the United States Space Command and its Space Force. With private space travel, nanosatellites, lunar exploration, and the proliferation of space …

North Ecliptic Pole Merging Galaxy Catalogue, W. J. Pearson, L. E. Suelves, S. C.-C. Ho, N. Oi, S. Brough, Benne Holwerda, A. M. Hopkins, T.-C. Huang, H. S. Hwang, L. S. Kelvin, S. J. Kim, Á. R. López-Sánchez, K. Małek, C. Pearson, A. Poliszczuk, A. Pollo, V. Rodriguez-Gomez, H. Shim, Y. Toba, L. Wang

Faculty and Staff Scholarship

Aims. We aim to generate a catalogue of merging galaxies within the 5.4 sq. deg. North Ecliptic Pole over the redshift range 0.0 < z < 0.3. To do this, imaging data from the Hyper Suprime-Cam are used along with morphological parameters derived from these same data.

Methods. The catalogue was generated using a hybrid approach. Two neural networks were trained to perform binary merger non-merger classifications: one for galaxies with z < 0.15 and another for 0.15 ≤ z < 0.30. Each network used the image and morphological parameters of a galaxy as input. The galaxies that were identified as merger candidates by the network were then visually checked by experts. The resulting mergers will be used to calculate the merger fraction as a function of redshift and compared with literature results.

Results. We found that 86.3% of galaxy mergers at z < 0.15 and 79.0% of mergers at 0.15 ≤ z < 0.30 are expected to be correctly identified by the networks. Of the 34 264 galaxies classified by the neural networks, 10 195 were found to be merger candidates. Of these, 2109 were visually identified to be merging galaxies. We find that the merger fraction increases with redshift, consistent with literature results from observations and simulations, and that there is a mild star-formation rate enhancement in the merger population of a factor of 1.102 ± 0.084.

A Monte Carlo Method For Evaluating Empirical Gyrochronology Models And Its Application To Wide Binary Benchmarks, Tomomi Otani, Ted Von Hippel, Derek Buzasi, Terry Oswalt, Alexander Stone-Martinez, Patrice Majewski

Publications

No abstract provided.

Physics Of Electromagnetic Counterparts Of Binary-Neutron-Star Mergers, Shunke Ai

UNLV Theses, Dissertations, Professional Papers, and Capstones

Binary neutron star (BNS) mergers are supposed to be the sources of a variety of astrophysical transients, including both gravitational wave (GW) and electromagnetic (EM) signals. The types and properties of the post-merger central product contain crucial information for many unsolved physical problems. Since the current GW detectors are not sensitive enough in kHz, only GWs from the inspiral phase can be detected, so that one cannot directly study the central products from GWs. EM signals can serve as probes to infer the type and properties of the central product. When a long-lived neutron star (NS) is formed after the …

Dust-Gas Dynamics Driven By The Streaming Instability With Various Pressure Gradients, Stanley Antedio Baronett

UNLV Theses, Dissertations, Professional Papers, and Capstones

The radial pressure gradient (RPG), along the midplane of gaseous protoplanetary disks (PPD) – planetary nurseries – poses a severe obstacle to planet formation. Micron-sized dust grains, embedded in the disc, must quickly grow to kilometer-sized planetesimals – the building blocks of planets – before fatally drifting inwards, by RPG-induced gas drag, into a central host star. However, the RPG simultaneously powers one of the most robust processes to overcome this radial-drift barrier: the streaming instability (SI). Spontaneously triggered, the SI aerodynamically concentrates drifting dust via drag-induced, coupled interactions and feedback with the surrounding gas. In particular, the non-linear phase …

The Effects Of Winds On Accretion Disks And Spectra Of X-Ray Binaries And Active Galactic Nuclei, Shalini Ganguly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Active galactic nuclei (AGNs) and X-ray binaries (XRBs) contain at their cores supermassive black holes (SMBH), and stellar mass black holes or neutron stars, respectively. These objects bind matter gravitationally, leading to the formation of accretion disks. The accretion of matter leads to efficient conversion of gravitational potential energy into radiation. When the force and/or energy imparted by this radiation on matter exceeds the attractive force due to the local gravitational field, it leads to the launching of matter in the form of outflows or winds. These outflows produce blueshifted (and occasionally redshifted) emission or absorption components in the spectra …

Miocene Ichnofaunas And Mammalian Communities In The Great Basin Region, Nevada And California, Annmarie R. Jones

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this dissertation is to document and interpret three new ichnofaunas and two fossil assemblages from the Neogene of Nevada and California. Ichnofossils are important for understanding behavior and geographical range of animals in the distant past and are key to locating and preserving sensitive material for future studies. I examined ichnofauna at three localities: two within the Mio-Pliocene Muddy Creek Formation of Nevada, and one within the Miocene China Ranch Beds of California. My research focuses primarily on (1) camelid and ursid ichnotaxa and how these new localities help in understanding the evolutionary history of these taxa …

Viability Of Energy And Fuel Sources For Interstellar Travel; Design And Feasibility Of The Construction Of Manned Interstellar Space Shuttles, Lukas Mittelman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The importance of proving the viability of interstellar transport and addressing its potential hazards and pitfalls is immense. If we do not look toward the future and examine what could be waiting for us, we are doing our children, our children’s children, and so on, a disservice. Here we must attempt to lay the groundwork for our future scientists, engineers, and adventurers. Asking and answering questions like, which propulsion and energy systems must we incorporate to send us through the cosmos? Will we utilize technologies known today, such as fossil fuel rockets, fission or fusion rockets, and antimatter drives (pion …

Terrestrial Planet Formation In M-Dwarf And Binary Star Systems, Anna C. Childs

UNLV Theses, Dissertations, Professional Papers, and Capstones

I examine circumbinary terrestrial planet formation in a gas free environment around various binary systems and terrestrial planet formation in a gaseous environment around M-dwarfs. While terrestrial cirumbinary planets have yet to be observed, this is likely due to observational bias. Motivated by recent observations of highly misaligned circumbinary gas disks, I perform a suite of n-body studies to understand the properties of terrestrial planets around various binary systems. In a polar alignment, a circumbinary disk is inclined by 90 degrees relative to the binary orbital plane. I find that terrestrial planet formation in a polar configuration may be as …

Fabrication And Characterization Of Superparamagnetic Nickel Ferrite Ferrofluid, D. Karthickraja, S. Karthi, G. Ajith Kumar, D. K. Sardar, Gamage Chamath Dannangoda, Karen S. Martirosyan, Niroj Kumar Sahu, M. Prasath, R. Arunima, E. L. Girija

Physics & Astronomy Faculty Publications

Because of their unique magnetic characteristics, magnetic nanoparticles are being used in various applications. We used a two-step method to create nickel ferrite ferrofluid in this study. The first step included hydrothermal preparation of oleic acid-capped nickel ferrite nanoparticles, followed by surface functionalization of the particles with citric acid, which made the nanoparticles hydrophilic. The materials' phase purity, functional groups, and magnetic behaviour were investigated. The production of mono-dispersed spherical nanoparticles with an average diameter of 9 ± 3.6 nm was shown by TEM images. With a blocking temperature of 53 K, ZFC-FC measurements verified the sample's …

Tesing Cababilities Of Proposed Telescope Lynx Through Simulated Bubbles In The Intracluster Medium, Sierra Rose Hauck

Honors Capstone Projects and Theses

No abstract provided.

Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, R. Abbott, T. Abbott, K. Ackley, F. Acernese, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

We present directed searches for continuous gravitational waves from the neutron stars in the Cassiopeia A (Cas A) and Vela Jr. supernova remnants. We carry out the searches in the LIGO detector data from the first six months of the third Advanced LIGO and Virgo observing run using the weave semicoherent method, which sums matched-filter detection-statistic values over many time segments spanning the observation period. No gravitational wave signal is detected in the search band of 20–976 Hz for assumed source ages greater than 300 years for Cas A and greater than 700 years for Vela Jr. Estimates from simulated …

Expanding The Library Of Planet Building Materials In Magrathea, Rosalie Chaleunsouck, Tristan Benally

Undergraduate Research Symposium Posters

Exoplanets are often modeled with fully-differentiated layers of iron, silicates, water, and gas. The large pressure and temperature ranges within each layer results in changes of phase and mineral equilibrium. MAGRATHEA is an open-course planet interior structure code with a large library of equations of state for planet building materials. This allows for the user to build detailed planet models and test differing measurements of the equation of state. We extend MAGRATHEA's library to include upper-mantle materials and various phases of iron cores. We show the impact of these materials on the characterization of rocky planet interiors.

Microbial Life In Deep-Subsurface Environments: The Role Of High Pressure In Biogeochemical Cycles, Cheyenne Brokaw

Undergraduate Research Symposium Posters

Ocean World: An ocean world is considered any planet or moon currently with a liquid ocean. While the deepest part of the Ocean (Mariana Trench, 11,000 mbsl, 110 Mpa) and the lithosphere host microbial life, it begs the question, How?

Using Supervised Learning Algorithms As A Follow-Up Method In The Search Of Gravitational Waves From Core-Collapse Supernovae, Javier M. Antelis, Marco Cavaglia, Travis Hansen, Mannuel D. Morales, Claudia Moreno, Soma Mukherjee, Marek J. Szczepańczyk, Michele Zanolin

Physics & Astronomy Faculty Publications

We present a follow-up method based on supervised machine learning (ML) to improve the performance in the search of gravitational wave (GW) bursts from core-collapse supernovae (CCSNe) using the coherent WaveBurst (cWB) pipeline. The ML model discriminates noise from signal events by using a set of reconstruction parameters provided by cWB as features. Detected noise events are discarded yielding a reduction in the false alarm rate (FAR) and the false alarm probability thus enhancing the statistical significance. We tested the proposed method using strain data from the first half of the third observing run of advanced LIGO, and CCSNe GW …

Determining The Sources Of The Zodiacal Cloud Using Relative Velocities Of Dust Particles From High-Resolution Spectroscopy, Philip B. Mann Iii

Beyond: Undergraduate Research Journal

The zodiacal cloud is the Solar System debris disk in which the Earth’s orbit is located. The dust that comprises the cloud comes from cometary, asteroidal, interstellar, and other source populations, but the relative ratios have proven hard to determine. However, asteroidal and cometary particles typically have different types of orbits, with asteroidal particles having more circular and lower inclination orbits than cometary particles. Accordingly, the relative velocities of these groups of particles with respect to Earth are also different, and measurements of these relative velocities can help distinguish between the sources. The spectrum of the zodiacal light contains solar …

The Next Small Step, Samiya Henry

Undergraduate Research and Scholarship Symposium

As of right now, NASA and other space programs are estimating that by 2026, there will be people living in Space. Whether it be the Moon or Mars, one cannot have a functional society without a proper source of laws, especially since no one country has ownership over space. "One Small Step" will produce this source of laws, called the “Space Bill of Rights,” that will outline important matters like the trade of resources, medical care, government officials, and will ensure the preservation of our physical and figurative footsteps in space. This Space Bill of Rights is made up of …

The Solar-Electric Sail: Application To Interstellar Migration And Consequences For Seti, Gregory Matloff

Publications and Research

The Solar-Electric Sail accelerates by reflecting positively charged solar wind ions. If it is used to propel an interstellar migration mission, its interstellar cruise velocity relative to the home star cannot exceed the solar wind velocity. In an effort to analytically determine interstellar cruise velocity for a 107 kg generation ship, a constant solar wind velocity within the heliosphere of a Sun-like star of 600 km/s is assumed. The solar wind proton density at 1 AU is also considered constant at 10 protons per cubic centimeter. Solar wind density is assumed to decrease with the inverse square of solar distance. …

Nano-Fabricated Atomic Waveguides For Inertial Measurements, Adrian S. Orozco

Physics & Astronomy ETDs

Atom-based inertial measurement systems can measure acceleration and rotation very precisely in the laboratory. The central element of these systems is atom interferometry where the phase shifts are sensitive to inertial forces experienced by the atom. This phenomenon has been used to make atom-based gravimeters, gradiometers, and gyroscopes. Recent effort has been made to make these systems more compact which require small size, light weight, and low power (SWaP). Nano-fabricated waveguides, such as photonic waveguides or optical nanofibers, offer a promising avenue to meet these goals. They have dimensions comparable to the guided light’s wavelength producing a mode that not …

Shining A Light On Dark Sky Week, Erik Johnson

Natural Science Faculty

Have you ever seen the Milky Way? For most Americans, it is impossible to see the band of light from the galaxy outside their homes. To be able to experience the night sky as our ancestors did, we have to travel to places away from light pollution.

International Dark Sky Week, which is happening April 22-30, celebrates the night sky and offers everyone a chance to reflect on the lighting choices made around their home and in their community.

Validation Of Accelerometry As A Digital Phenotyping Measure Of Negative Symptoms In Schizophrenia, Gregory P. Strauss, Ian M. Raugh, Luyu Zhang, Lauren Luther, Hannah C. Chapman, Daniel N. Allen, Brian Kirkpatrick, Alex S. Cohen

Physics & Astronomy Faculty Research

Negative symptoms are commonly assessed via clinical rating scales; however, these measures have several inherent limitations that impact validity and utility for their use in clinical trials. Objective digital phenotyping measures that overcome some of these limitations are now available. The current study evaluated the validity of accelerometry (ACL), a passive digital phenotyping method that involves collecting data on the presence, vigor, and variability of movement. Outpatients with schizophrenia (SZ: n = 50) and demographically matched healthy controls (CN: n = 70) had ACL continuously recorded from a smartphone and smartband for 6 days. Active digital phenotyping assessments, including surveys …

Search Of The Early O3 Ligo Data For Continuous Gravitational Waves From The Cassiopeia A And Vela Jr. Supernova Remnants, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

We present directed searches for continuous gravitational waves from the neutron stars in the Cassiopeia A (Cas A) and Vela Jr. supernova remnants. We carry out the searches in the LIGO detector data from the first six months of the third Advanced LIGO and Virgo observing run using the weave semicoherent method, which sums matched-filter detection-statistic values over many time segments spanning the observation period. No gravitational wave signal is detected in the search band of 20–976 Hz for assumed source ages greater than 300 years for Cas A and greater than 700 years for Vela Jr. Estimates from simulated …