Astrophysics and Astronomy Commons^™

Pipeline For Variable Star Detection And Eclipsing Binary Characterization, Moises Castillo

Theses and Dissertations

Stars have been observed and recorded since ancient times. Practices of documenting brightness led to observations of variability. Optical CCD observations of eclipsing binary stars were made with instruments at UTRGV Dr. Cristina Valeria Torres Memorial Astronomical Observatory. There are two main goals for this project. The first goal is to create a pipeline written in python (lightcurator) that creates a framework for detecting variable stars. The pipeline starts by creating a list of ccd frames written in FITS format of an eclipsing binary star observation. These object frames are expected to be already reduced, but lightcurator provides tools to …

Adsorption Driven Regolith-Atmospheric Water Vapor Transfer On Mars: An Analysis Of Phoenix Tecp Data, Holly Nicole Farris

Graduate Theses and Dissertations

NASA’s Phoenix mission allowed for investigations of Martian diurnal water vapor cycles through the collection of temperature, relative humidity, and electric conductivity data by the Thermal and Electric Conductivity Probe (TECP) instrument. Using this data and previous experimental data, we propose a regolith-driven adsorption-desorption regime at the Phoenix landing site, where parameters intrinsic to the regolith are controlling localized relative humidity at the surface. To constrain these parameters, we model adsorption as a function of temperature and relative humidity across various Mars-relevant materials, defined by two layer-based adsorption theories: Langmuir (monolayer) and Brunauer-Emmett-Teller or BET (multilayer). Langmuir serves as an …

Electron Energization By Parallel Electric Fields In Poloidal Standing Waves, P. A. Damiano, Eun-Hwa Kim, Jay R. Johnson, P. Porazik

Faculty Publications

A hybrid gyrofluid‐kinetic electron model is adapted and used to simulate poloidal standing modes for different electron temperatures and azimuthal mode numbers. As in previous studies of toroidal standing modes, mirror force effects lead to increased parallel potential drops, monoenergetic electron energization, and wave energy dissipation as the ambient electron temperature is increased. A similar trend is also observed when the electron temperature is held fixed and the azimuthal mode number increased—owing to the narrowing of the azimuthal flux tube width, which necessitates more electron energization to carry the increased parallel current density. In both cases, the increase in electron …

Hyper Wide Field Imaging Of The Local Group Dwarf Irregular Galaxy Ic 1613: An Extended Component Of Metal-Poor Stars, Ragadeepika Pucha, Jeffrey Carlin, Beth Willman, Jay Strader, David Sand, Keith Bechtol, Jean Brodie, Denija Crnojević, Duncan Forbes, Christopher Garling, Jonathan Hargis, Annika Peter, Aaron Romanowsky

Faculty Publications

Stellar halos offer fossil evidence for hierarchical structure formation. Since halo assembly is predicted to be scale-free, stellar halos around low-mass galaxies constrain properties such as star formation in the accreted subhalos and the formation of dwarf galaxies. However, few observational searches for stellar halos in dwarfs exist. Here we present gi photometry of resolved stars in isolated Local Group dwarf irregular galaxy IC 1613 (M sstarf ~ 108 M ⊙). These Subaru/Hyper Suprime-Cam observations are the widest and deepest of IC 1613 to date. We measure surface density profiles of young main-sequence, intermediate to old red giant branch, and …

Fabrication Of Core–Shell Cofe2o4@Hap Nanoparticles: A Novel Magnetic Platform For Biomedical Applications, D. Karthickraja, S. Karthi, G. A. Kumar, Gamage Chamath Dannangoda, Karen S. Martirosyan, E. L. Girija

Physics & Astronomy Faculty Publications

Core–shell CoFe2O4@HAp magnetic nanoparticles were successfully prepared by a simple two-step hydrothermal process, and their physicochemical and magnetic properties were studied. X-ray diffraction and Fourier transform infrared spectroscopy of the as-synthesized samples reveal that the nanoparticles are composed of both phases (HAp@CoFe2O4). The core–shell formation was confirmed by TEM and from the magnetization studies using a vibrating sample magnetometer (VSM), and the ferromagnetic nature of the synthesized core–shell nanoparticles at room temperature was confirmed by saturation magnetization (Ms) and coercivity values of 9.04 emu g−1 and 0.1 T, respectively. It has been observed that heat treatment enhanced the …

Spatially Resolved Stellar Kinematics Of The Ultra-Diffuse Galaxy Dragonfly 44. I. Observations, Kinematics, And Cold Dark Matter Halo Fits, Pieter Van Dokkum, Asher Wasserman, Shany Danieli, Roberto Abraham, Jean Brodie, Charlie Conroy, Duncan Forbes, Christopher Martin, Matt Matuszewski, Aaron Romanowsky, Alexa Villaume

Faculty Publications

We present spatially resolved stellar kinematics of the well-studied ultra-diffuse galaxy (UDG) Dragonfly 44, as determined from 25.3 hr of observations with the Keck Cosmic Web Imager. The luminosity-weighted dispersion within the half-light radius is ${\sigma }_{1/2}={33}_{-3}^{+3}$ km s−1, lower than what we had inferred before from a DEIMOS spectrum in the Hα region. There is no evidence for rotation, with ${V}_{\max }/\langle \sigma \rangle \lt 0.12$ (90% confidence) along the major axis, in possible conflict with models where UDGs are the high-spin tail of the normal dwarf galaxy distribution. The spatially averaged line profile is more peaked than a …

Quantum Algorithms With Applications To Simulating Physical Systems, Anirban Ch Narayan Chowdhury

Physics & Astronomy ETDs

The simulation of quantum physical systems is expected to be an important application for quantum computers. The work presented in this dissertation aims to improve the resource requirements of quantum computers for solving simulation problems, by providing both novel quantum algorithms and improved implementations of existing ones. I present three main results that cover diverse aspects of simulation including equilibrium physics, the preparation of useful quantum states, and simulations based on classical stochastic processes. The results rely on established quantum algorithms and other recent techniques which I review. My first original contribution is a new quantum algorithm to sample from …

Circumbinary Disk Inner Radius As A Diagnostic For Disk–Binary Misalignment, Alessia Franchini, Stephen H. Lubow, Rebecca G. Martin

Physics & Astronomy Faculty Research

We investigate the misalignment of the circumbinary disk around the binary HD 98800 BaBb with eccentricity e sime 0.8. Kennedy et al. observed the disk to be either at an inclination of 48° or polar aligned to the binary orbital plane. Their simulations showed that alignment from 48° to a polar configuration can take place on a shorter timescale than the age of this system. We perform hydrodynamical numerical simulations in order to estimate the cavity size carved by the eccentric binary for different disk inclinations as an independent check of polar alignment. Resonance theory suggests that torques on the …

Searching For Supermassive Binary Black Holes And Their Gravitational Waves, Karishma Bansal

Physics & Astronomy ETDs

The recent discovery of gravitational waves (GWs) by the LIGO collaboration has opened a new observing window on the universe, but it is limited to the GWs in the frequency range of 10-1000 Hz. The main motivation of this thesis is to consider the possibility of detecting low frequency (nHz) GWs. In the pursuit of these waves, we need to understand their source of origin and build a detector with the required sensitivity. Low-frequency waves are expected as a result of coalescing binary supermassive black holes (SMBBHs). We hope to detect these waves in the near future using pulsar timing …

Studying The Properties Of Sf6 Gas Mixtures For Directional Dark Matter Detection, Randy J. Lafler

Physics & Astronomy ETDs

Although dark matter comprises approximately 85\% of the matter content of the universe, direct detection of dark matter remains elusive. As the available parameter space for dark matter candidates is pushed to lower and lower limits, the demand for larger, more sensitive detectors continues to grow. Although upscaling the detector improves the sensitivity, it greatly increases the cost and complexity of the experiment. Even after a dark matter signal is detected, there remains the possibility that an unknown background mimics the dark matter signal. Consequently, verifying the dark matter origin of a detection signal is an issue for any dark …

Regional Distribution Of Mesospheric Small‐Scale Gravity Waves During Deepwave, Pierre-Dominique Pautet, Michael J. Taylor, S. D. Eckermann, Neal R. Criddle

Publications

The Deep Propagating Gravity Wave Experiment project took place in June and July 2014 in New Zealand. Its overarching goal was to study gravity waves (GWs) as they propagate from the ground up to ~100 km, with a large number of ground‐based, airborne, and satellite instruments, combined with numerical forecast models. A suite of three mesospheric airglow imagers operated onboard the NSF Gulfstream V (GV) aircraft during 25 nighttime flights, recording the GW activity at OH altitude over a large region (>7,000,000 km²). Analysis of this data set reveals the distribution of the small‐scale GW mean power …

On Neutralization Of Charged Black Holes, Yi Gong, Zhoujian Cao, He Gao, Bing Zhang

Physics & Astronomy Faculty Research

For non-spinning, charged (Reissner–Nordström) black holes, the particles with an opposite sign of charge with respect to that of the black hole will be pulled into the black hole by the extra electromagnetic force. Such a hole will be quickly neutralized so that there should not exist significantly charged, non-spinning black holes in the universe. The case of spinning, charged (Kerr–Newmann, KN) black holes is more complicated. For a given initial position and initial velocity of the particle, an oppositely charged particle does not always more easily fall into the black hole than a neutral particle. The possible existence of …

Lanczos-Boosted Numerical Linked-Cluster Expansion For Quantum Lattice Models, Krishnakumar Bhattaram, Ehsan Khatami

Faculty Research, Scholarly, and Creative Activity

Numerical linked-cluster expansions allow one to calculate finite-temperature properties of quantum lattice models directly in the thermodynamic limit through exact solutions of small clusters. However, full diagonalization is often the limiting factor for these calculations. Here we show that a partial diagonalization of the largest clusters in the expansion using the Lanczos algorithm can be as useful as full diagonalization for the method while mitigating some of the time and memory issues. As test cases, we consider the frustrated Heisenberg model on the checkerboard lattice and the Fermi-Hubbard model on the square lattice. We find that our approach can surpass …

Decoding The History Of The Early Solar System Using Comet Volatile Compositions, Nathan Roth

Dissertations

Understanding the evolution of the solar system, as well as its current volatile content, requires knowledge of the initial conditions present in the solar nebula. As some of the first objects to accrete in the solar nebula, cometary nuclei are among the most primitive remnants of solar system formation, and their present-day volatile composition likely reflects the composition and conditions where (and when) they formed. As such, the volatile compositions of cometary nuclei may serve as "fossils" of solar system formation. High-resolution near-infrared spectroscopy offers a valuable tool for sampling the primary volatile (i.e., ices subliming directly from the nucleus) …

Preservation Of Our Astronomical Heritage: State Of The Profession White Paper For Astro2020, James Lattis, Wayne Osborn, Terry D. Oswalt, Jennifer Lynn Bartlett, Elizabeth Griffin, Thomas Hockey, Stephen Mccluskey, Alexei A. Pevtsov, Sara Schechner, Virginia Trimble

Publications

We argue that it is essential that the Astro2020 survey of the present state of American astronomy and the recommendations for the next decade address the issue of ensuring preservation of, and making more discoverable and accessible, the field’s rich legacy materials. These include both archived observations of scientific value and items of historical importance. Much of this heritage likely will be lost if action is not taken in the next decade. It is proposed that the decadal plan include recommendations on (1) compiling a list of historic sites and development of models for their preservation, (2) carrying out a …

All-Sky Search For Continuous Gravitational Waves From Isolated Neutron Stars Using Advanced Ligo O2 Data, Tiffany Summerscales

Faculty Publications

We present results of an all-sky search for continuous gravitational waves (CWs), which can be produced by fast spinning neutron stars with an asymmetry around their rotation axis, using data from the second observing run of the Advanced LIGO detectors. Three different semicoherent methods are used to search in a gravitational-wave frequency band from 20 to 1922 Hz and a first frequency derivative from −1×10⁻⁸ to 2×10⁻⁹  Hz/s. None of these searches has found clear evidence for a CW signal, so upper limits on the gravitational-wave strain amplitude are calculated, which for this broad range in parameter space …

Circumstellar Sio Masers In The Bulge Asymmetries And Dynamical Evolution Survey, Michael Cullen Stroh

Physics & Astronomy ETDs

The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to explore the complex structure of the inner Galaxy and Galactic Bulge, by using the 43 GHz receivers at the Karl G. Jansky Very Large Array (VLA) and the 86 GHz receivers at the Atacama Large Millimeter/submillimeter Array (ALMA) to observe SiO maser lines in red giant stars. The SiO maser transitions occur at radio frequencies, where extinction is negligible, thus allowing a dense sampling of line-of-sight velocities in the most crowded regions of the Milky Way.

The overall goal of this thesis is to characterize the SiO masers in the …

New Constraints On Early-Type Galaxy Assembly From Spectroscopic Metallicities Of Globular Clusters In M87, Alexa Villaume, Aaron Romanowsky, Jean Brodie, Jay Strader

Faculty Publications

The observed characteristics of globular cluster (GC) systems, such as metallicity distributions, are commonly used to place constraints on galaxy formation models. However, obtaining reliable metallicity values is particularly difficult because of our limited means to obtain high quality spectroscopy of extragalactic GCs. Often, "color–metallicity relations" are invoked to convert easier-to-obtain photometric measurements into metallicities, but there is no consensus on what form these relations should take. In this paper we make use of multiple photometric data sets and iron metallicity values derived from applying full-spectrum stellar population synthesis models to deep Keck/LRIS spectra of 177 GCs centrally located around …

A Radial Velocity Survey Of Embedded Sources In The Rho Ophiuchi Cluster, Timothy Sullivan, Bruce Wilking, Thomas Greene, Lindsey Lisalda, Erika Gibb, Chemeda Ejeta

Physics Faculty Works

No abstract provided.

A Search For Analogs Of Kic 8462852 (Boyajian’S Star): A Proof Of Concept And The First Candidates, Edward G. Schmidt

Edward Schmidt Publications

The seemingly normal F dwarf, KIC 8462852 (a.k.a. Boyajian’s Star), has been observed to exhibit two types of behavior unique among known variable stars: infrequent episodes of small brightness dips and a long-term decline in brightness between the dips. No satisfactory mechanism has been found for this behavior, at least in part, because there is only one known example. To begin to rectify this, we have searched for other stars exhibiting similar dipping behavior using the Northern Sky Variability Survey and have used data from the All Sky Automated Survey for Supernovae to further investigate the behavior. Twenty-one stars are …

Task-Layer Multiplicity As A Measure Of Community Level Health, Phil Fraundorf

Physics Faculty Works

Te insights of many disciplines, and of commonsense, about individual-level well-being might be strengthened by a shif in focus to community-level well-being in a way that respects belief systems as well as the power of each individual. We start with the jargon of complex systems and the possibility that a small number of broken symmetries, marked by the edges of a hierarchical series of physical subsystem types, underlie the delicate correlation-based complexity of life on our planet’s surface. We show that an information-theory-inspired model of attention-focus on correlation layers, which looks in/out from the boundaries of skin, family, and culture, …

“Where Is Everybody?” Fermi’S Paradox, Evolution, And Sin, Noreen L. Herzfeld

Computer Science Faculty Publications

The Search for Extraterrestrial Intelligence (SETI) project has been scanning the heavens for signs of intelligent life for almost half a century. So far, nothing. This raises the question physicist Enrico Fermi asked, "Where is everybody?" The probability of intelligent life on another planet is high so why the silence? Technological civilizations may be short-lived. The mechanisms of evolution that lead to intelligent life and technological development also lead to propensities traditionally labeled as sin. These propensities make it difficult for technological civilizations to survive long enough to escape their home planet.

Magnetic Ob[A] Stars With Tess: Probing Their Evolutionary And Rotational Properties (Mobster) – I. First-Light Observations Of Known Magnetic B And A Stars, A. David-Uraz, C. Neiner, J. Sikora, D. M. Bowman, V. Petit, S. Chowdhury, G. Handler, M. Pergeorelis, M. Cantiello, David H. Cohen, C. Erba, Z. Keszthelyi, V. Khalack, O. Kobzar, O. Kochukhov, J. Labadie-Bartz, C. C. Lovekin, R. Macinnis, S. P. Owocki, H. Pablo, M. E. Shultz, A. Ud-Doula, G. A. Wade, Mobster Collaboration

Physics & Astronomy Faculty Works

In this paper we introduce the MOBSTER collaboration and lay out its scientific goals. We present first results based on the analysis of 19 previously known magnetic O, B, and A stars observed in 2-min cadence in sectors 1 and 2 of the Transiting Exoplanet Survey Satellite (TESS) mission. We derive precise rotational periods from the newly obtained light curves and compare them to previously published values. We also discuss the overall photometric phenomenology of the known magnetic massive and intermediate-mass stars and propose an observational strategy to augment this population by taking advantage of the high-quality observations produced by …

The L 98-59 System: Three Transiting, Terrestrial-Size Planets Orbiting A Nearby M Dwarf, V. B. Kostov, J. E. Schlieder, T. Barclay, E. V. Quintana, K. D. Colón, J. Brande, K. A. Collins, A. D. Feinstein, S. Hadden, S. R. Kane, L. Kreidberg, E. Kruse, C. Lam, E. Matthews, B. T. Montet, F. J. Pozuelos, K. G. Stassun, J. G. Winters, G. Ricker, R. Vanderspek, D. Latham, S. Seager, J. Winn, J. M. Jenkins, D. Afanasev, J. J. D. Armstrong, G. Arney, P. Boyd, G. Barentsen, K. Barkaoui, N. E. Batalha, C. Beichman, D. Bayliss, C. Burke, A. Burdanov, L. Cacciapuoti, A. Carson, D. Charbonneau, J. Christiansen, D. Ciardi, M. Clampin, K. I. Collins, D. M. Conti, J. Coughlin, G. Covone, I. Crossfield, L. Delrez, S. Domagal-Goldman, C. Dressing, E. Ducrot, Z. Essack, M. E. Everett, T. Fauchez, D. Foreman-Mackey, T. Gan, E. Gilbert, M. Gillon, E. Gonzales, A. Hamann, C. Hedges, H. Hocutt, K. Hoffman, E. P. Horch, K. Home, S. Howell, S. Hynes, M. Ireland, J. M. Irwin, G. Isopi, Eric L.N. Jensen, E. Jehin, L. Kaltenegger, J. F. Kielkopf, R. Kopparapu, N. Lewis, E. Lopez, J. J. Lissauer, A. W. Mann, F. Mallia, A. Mandell, R. A. Matson, T. Mazeh, T. Monsue, S. E. Moran, V. Moran, C. V. Morley, B. Morris, P. Muirhead, K. Mukai, S. Mullally, F. Mullally, C. Murray, N. Narita, E. Palle, D. Pidhorodetska, D. Quinn, H. Relles, S. Rinehart, M. Ritsko, J. E. Rodriguez, P. Rowden, J. F. Row, D. Sebastian, R. Sefako, S. Shahaf, A. Shporer, N. Tañón Reyes, P. Tenenbaum, E. B. Ting, J. D. Twicken, G. T. Van Belle, L. Vega, J. Volosin

Physics & Astronomy Faculty Works

We report the Transiting Exoplanet Survey Satellite (TESS) discovery of three terrestrial-size planets transiting L 98-59 (TOI-175, TIC 307210830)—a bright M dwarf at a distance of 10.6 pc. Using the Gaia-measured distance and broadband photometry, we find that the host star is an M3 dwarf. Combined with the TESS transits from three sectors, the corresponding stellar parameters yield planet radii ranging from 0.8 R_⊕ to 1.6 R_⊕. All three planets have short orbital periods, ranging from 2.25 to 7.45 days with the outer pair just wide of a 2:1 period resonance. Diagnostic tests produced by the TESS …

Embedding Climate Change Engagement In Astronomy Education And Research, Kathryn Williamson, Travis A. Rector, James D. Lowenthal

Astronomy: Faculty Publications

This White Paper is a call to action for astronomers to respond to climate change with a large structural transition within our profession. Many astronomers are deeply concerned about climate change and act upon it in their personal and professional lives, and many organizations within astronomy have incorporated incremental changes. We need a collective impact model to better network and grow our efforts so that we can achieve results that are on the scale appropriate to address climate change at the necessary level indicated by scientific research; e.g., becoming carbon neutral by 2050. We need to implement strategies within two …

Brightest Cluster Galaxy Evolution Exploration: Comparing The Separation Of Cluster X-Ray Light And Visible Wavelength Galaxy Light With Spectral Data, Matthew Aaron Salinas

Physics

Brightest Cluster Galaxies (BCGs), the brightest galaxy in a cluster of hundreds to thousands of galaxies, are some of the biggest, brightest, and most massive galaxies in the universe. Characterizing a BCG can help discover more about galaxy evolution - the aging, changing, and possible merging (collisions) of galaxies. This project involves determining the separation of the peak of x-ray emission of the galaxy cluster, and the peak of visible emission of the BCG to characterize the system as being disturbed or undisturbed that can then lead to discoveries about its formation and evolution. We have found that 17.4% of …

Tests Of General Relativity With Gw170817, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration

Faculty Publications

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due …

An Emission Spectrum For Wasp-121b Measured Across The 0.8–1.1 Μm Wavelength Range Using The Hubble Space Telescope, Thomas Mikal-Evans, David K. Sing, Jayesh M. Goyal, Benjamin Drummond, Aarynn L. Carter, Gregory W. Henry, Hannah R. Wakeford, Nikole K. Lewis, Mark S. Marley, Pascal Tremblin, Nikolay Nikolov, Tiffany Kataria, Drake Deming, Gilda E. Ballester

Information Systems and Engineering Management Research Publications

WASP-121b is a transiting gas giant exoplanet orbiting close to its Roche limit, with an inflated radius nearly double that of Jupiter and a dayside temperature comparable to a late M dwarf photosphere. Secondary eclipse observations covering the 1.1–1.6μm wavelength range have revealed an atmospheric thermal inversion on the dayside hemisphere, likely caused by high-altitude absorption at optical wavelengths. Here we present secondary eclipse observations made with the Hubble Space Telescope Wide Field Camera 3 spectrograph that extend the wavelength coverage from 1.1μm down to 0.8μm⁠. To determine the atmospheric properties from the measured eclipse spectrum, we performed a retrieval …

Narrow-Band Search For Gravitational Waves From Known Pulsars Using The Second Ligo Observing Run, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration

Faculty Publications

Isolated spinning neutron stars, asymmetric with respect to their rotation axis, are expected to be sources of continuous gravitational waves. The most sensitive searches for these sources are based on accurate matched filtering techniques that assume the continuous wave to be phase locked with the pulsar beamed emission. While matched filtering maximizes the search sensitivity, a significant signal-to-noise ratio loss will happen in the case of a mismatch between the assumed and the true signal phase evolution. Narrow-band algorithms allow for a small mismatch in the frequency and spin-down values of the pulsar while coherently integrating the entire dataset. In …

Searches For Gravitational Waves From Known Pulsars At Two Harmonics In 2015–2017 Ligo Data, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Robert Stone

Physics & Astronomy Faculty Publications

We present a search for gravitational waves from 222 pulsars with rotation frequencies ≳10 Hz. We use advanced LIGO data from its first and second observing runs spanning 2015–2017, which provides the highest-sensitivity gravitational-wave data so far obtained. In this search we target emission from both the l = m = 2 mass quadrupole mode, with a frequency at twice that of the pulsar's rotation, and the l = 2, m = 1 mode, with a frequency at the pulsar rotation frequency. The search finds no evidence for gravitational-wave emission from any pulsar at either frequency. For the l = …