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Articles 661 - 690 of 9201

Full-Text Articles in Physical Sciences and Mathematics

X-Ray Spectroscopy Of The O Supergiant Ζ Puppis Indicates Surprising Variation In The Wind Mass-Loss Rate On Years Timescales, Jiaming Wang , '22 Apr 2022

X-Ray Spectroscopy Of The O Supergiant Ζ Puppis Indicates Surprising Variation In The Wind Mass-Loss Rate On Years Timescales, Jiaming Wang , '22

Senior Theses, Projects, and Awards

We apply two mass-loss rate diagnostics described in the thesis on Chandra and XMM-Newton X-ray spectroscopic measurements of ζ Pup, one of the most luminous stars in the Milky Way and one of the closest O stars to Earth. Emission line profile analysis from new long Chandra grating observations taken during 2018 and 2019 indicates a significant 40% increase in ζ Pup’s wind mass-loss rate as compared to data taken in Chandra’s first observation cycle in 2000. Broadband spectral modeling of 20 years of XMM observations also reveal non-periodic wind mass-loss rate variation at a 40% level on timescales …

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Mms Observations Of The Kelvin-Helmholtz Instability And Associated Ion Scale Waves, Rachel C. Rice Apr 2022

Mms Observations Of The Kelvin-Helmholtz Instability And Associated Ion Scale Waves, Rachel C. Rice

Doctoral Dissertations and Master's Theses

The detailed mechanisms coupling the solar wind to Earth's magnetosphere are not yet fully understood. Solar wind plasma is heated non-adiabatically as it penetrates the magnetosphere, and this process must span scale sizes. Reconnection alone is not able to account for the observed heating; other mechanisms must be at work. One potential process is the Kelvin-Helmholtz instability (KHI). The KHI is a convective instability which operates at the fluid scale in plasmas, but is capable of driving secondary process at smaller scales. Previous work has shown evidence of magnetic reconnection, various ion scale wave modes, mode conversion, and turbulence associated …

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Reimagining Near-Earth Space Policy In A Post-Covid World, John C. Barentine, Jessica Heim, Aparna Venkatesan, James Lowenthal, Monica Vidaurri Apr 2022

Reimagining Near-Earth Space Policy In A Post-Covid World, John C. Barentine, Jessica Heim, Aparna Venkatesan, James Lowenthal, Monica Vidaurri

Astronomy: Faculty Publications

Our planet and our species are at an existential crossroads. In the long term, climate change threatens to upend life as we know it, while the ongoing COVID-19 pandemic revealed that the world is unprepared and ill-equipped to handle acute shocks to its many systems. These shocks exacerbate the inequities and challenges already present prior to COVID in ways that are still evolving in unpredictable directions. As weary nations look toward a post-COVID world, we draw attention to both the injustice and many impacts of the quiet occupation of near-Earth space, which has rapidly escalated during this time of global …

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Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales Apr 2022

Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence …

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Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Apr 2022

Search For Gravitational Waves Associated With Gamma-Ray Bursts Detected By Fermi And Swift During The Ligo–Virgo Run O3b, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence …

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B-Flavor Tagging At Belle Ii, F. Abudinén, N. Akopov, A. Aloisio, V. Babu, Sw Banerjee, M. Bauer, J. V. Bennett, F. U. Bernlochner, M. Bessner, S. Bettarini, T. Bilka, S. Bilokin, D. Biswas, D. Bodrov, J. Borah, M. Bračko, P. Branchini, A. Budano, M. Campajola Apr 2022

B-Flavor Tagging At Belle Ii, F. Abudinén, N. Akopov, A. Aloisio, V. Babu, Sw Banerjee, M. Bauer, J. V. Bennett, F. U. Bernlochner, M. Bessner, S. Bettarini, T. Bilka, S. Bilokin, D. Biswas, D. Bodrov, J. Borah, M. Bračko, P. Branchini, A. Budano, M. Campajola

Faculty and Student Publications

We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom ([InlineMediaObject not available: see fulltext.]) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic [InlineMediaObject not available: see fulltext.] decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of 62.8 fb- 1, collected at the [InlineEquation not available: see fulltext.] resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be εeff=(30.0±1.2(stat)±0.4(syst))%for …

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Luminosity With Large Amplitude Pulses After The Initial Breakdown Stage In Intracloud Lightning Flashes, Maribeth Stolzenburg, Thomas C. Marshall, Sampath Bandara, Raymond Siedlecki Apr 2022

Luminosity With Large Amplitude Pulses After The Initial Breakdown Stage In Intracloud Lightning Flashes, Maribeth Stolzenburg, Thomas C. Marshall, Sampath Bandara, Raymond Siedlecki

Faculty and Student Publications

Optical data are presented for two intracloud flashes in which there were five events having large amplitude, bipolar electric field change (E-change) pulses and strong VHF emissions. These bright events occurred 18.98–67.33 ms after the initiating event and 10–59 ms after the end of the initial breakdown stage. The three largest events were coincident with WorldWide Lightning Location Network detections of the sort previously associated with terrestrial gamma-ray flashes (TGFs); these pulses had range-normalized E-change amplitudes of 8.73, 8.33, and 3.81 V/m and estimated peak current magnitudes of 262, 250, and 114 kA. The other two events were 3.20 and …

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Galaxy And Mass Assembly (Gama): The Weak Environmental Dependence Of Quasar Activity At 0.1 < Z < 0.35, Clare F. Wethers, Nischal Acharya, Roberto De Propris, Jari Kotilainen, Ivan K. Baldry, Sarah Brough, Simon P. Driver, Alister W. Graham, Benne Holwerda, Andrew M. Hopkins, Angel R. López-Sánchez, Jonathan Loveday, Steven Phillipps, Kevin A. Pimbblet, Edward Taylor, Lingyu Wang, Angus H. Wright Apr 2022

Galaxy And Mass Assembly (Gama): The Weak Environmental Dependence Of Quasar Activity At 0.1 < Z < 0.35, Clare F. Wethers, Nischal Acharya, Roberto De Propris, Jari Kotilainen, Ivan K. Baldry, Sarah Brough, Simon P. Driver, Alister W. Graham, Benne Holwerda, Andrew M. Hopkins, Angel R. López-Sánchez, Jonathan Loveday, Steven Phillipps, Kevin A. Pimbblet, Edward Taylor, Lingyu Wang, Angus H. Wright

Faculty and Staff Scholarship

Understanding the connection between nuclear activity and galaxy environment remains critical in constraining models of galaxy evolution. By exploiting the extensive cataloged data from the Galaxy and Mass Assembly survey, we identify a representative sample of 205 quasars at 0.1 < z < 0.35 and establish a comparison sample of galaxies, closely matched to the quasar sample in terms of both stellar mass and redshift. On scales <1 Mpc, the galaxy number counts and group membership of quasars appear entirely consistent with those of the matched galaxy sample. Despite this, we find that quasars are ∼1.5 times more likely to be classified as the group center, indicating a potential link between quasar activity and cold gas flows or galaxy interactions associated with rich group environments. On scales of ∼a few Mpc, the clustering strengths of both samples are statistically consistent, and beyond 10 Mpc, we find no evidence that quasars trace large-scale structures any more than the galaxy control sample. Both populations are found to prefer intermediate-density sheets and filaments to either very high-density environments or very low-density environments. This weak dependence of quasar activity on galaxy environment supports a paradigm in which quasars represent a phase in the lifetime of all massive galaxies and in which secular processes and a group-centric location are the dominant triggers of quasars at low redshift.

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Are Long-Period Exoplants Around Cool Stars More Common Than We Thought?, Emily Jane Safron Mar 2022

Are Long-Period Exoplants Around Cool Stars More Common Than We Thought?, Emily Jane Safron

LSU Doctoral Dissertations

The Kepler mission has been the catalyst for discovery of nearly 5,000 confirmed and candidate exoplanets. The majority of these candidates orbit Sun-like stars, and have orbital periods comparable to or shorter than that of the Earth, due to the selection bias inherent in the transit method and the limitations of automated transit search algorithms. We aim to develop a richer understanding of the population of exoplanets around the lowest-mass stars, the M spectral type. We are particularly interested in exoplanets with long orbital periods, which are difficult or impossible to find using standard transit search algorithms. In our study, …

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Possible Studies On Generalized Parton Distributions And Gravitational Form Factors In Neutrino Reactions, Shunzo Kumano, Roberto Petti Mar 2022

Possible Studies On Generalized Parton Distributions And Gravitational Form Factors In Neutrino Reactions, Shunzo Kumano, Roberto Petti

Faculty Publications

Spacelike and timelike generalized parton distributions (GPDs) have been investigated in charged-lepton scattering and electron-positron collisions via deeply virtual Compton scattering and two-photon processes, respectively. Furthermore, we expect that hadron-accelerator-facility measurements will be performed in future. The GPDs will play a crucial role in clarifying the origins of hadron spins and masses in terms of quarks and gluons. It is also possible to probe internal pressure within hadrons for understanding their stability. Gravitational form factors of hadrons used to be considered as a purely academic subject because gravitational interactions are too weak to be measured in microscopic systems. However, due …

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Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang Mar 2022

Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, R. Abbott, T. D. Abbott, F. Acernese, Teviet Creighton, Mario C. Diaz, F. Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon …

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Hadron-Quark Phase Transition At Finite Density In The Presence Of A Magnetic Field: Anisotropic Approach, Efrain J. Ferrer, Aric Hackebill Mar 2022

Hadron-Quark Phase Transition At Finite Density In The Presence Of A Magnetic Field: Anisotropic Approach, Efrain J. Ferrer, Aric Hackebill

Physics and Astronomy Faculty Publications and Presentations

We investigate the hadron-quark phase transition at finite density in the presence of a magnetic field taking into account the anisotropy created by a uniform magnetic field in the system’s equations of state. We find a new anisotropic equilibrium condition that will drive the first-order phase transition along the boundary between the two phases. Fixing the magnetic field in the hadronic phase, the phase transition is realized by increasing the baryonic chemical potential at zero-temperature. It is shown that the magnetic field is mildly boosted after the system transitions from the hadronic to the quark phase. The magnetic-field discontinuity between …

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The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis, Courtney Lauren Crawford Mar 2022

The Spectra Of Hydrogen-Deficient Carbon Stars: The Effects Of Evolution And Nucleosynthesis, Courtney Lauren Crawford

LSU Doctoral Dissertations

The rare class of stars known as the Hydrogen-deficient Carbon (HdC) stars includes the R Coronae Borealis (RCB) variables and the non-variable Dustless HdC (dLHdC) stars. These stars are believed to be formed via the merger of two white dwarf (WD) stars. They are known to exhibit many spectral peculiarities, such as partial helium burning products, enhancement of s-processed material and severe hydrogen-deficiency. In this work I explore many facets of HdC evolution. I begin by creating 18 HdC models in the stellar evolution code Modules for Experiments in Stellar Astrophysics (MESA) by merging two WD progenitors and evolving the …

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Dayside Auroral Activity, Aine Merritt, Gerard J. Fasel Mar 2022

Dayside Auroral Activity, Aine Merritt, Gerard J. Fasel

Seaver College Research And Scholarly Achievement Symposium

The dayside aurora is greatly influenced by the solar wind. Many different types of dayside auroral features have been identified, including poleward-moving auroral forms (PMAFs), throat aurora, shock aurora, and diffuse aurora. This study looks at the dayside auroral activity using the BACC ground-based all-sky-cameras located in both Longyearbyen (Kjell Henriksen Observatory) and Ny-Alesund, Svalbard. There are times when PMAFs peel off the dayside auroral oval in an ordered fashion, elongated east-west arcs moving poleward. At other times, the dayside aurora displays arcs that have extreme brightening moving through the arcs as they exhibit swirls and become a bit chaotic …

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Cepheid Variable Light Curve Analysis On The Embry-Riddle 1-Meter Telescope, Kayla Taylor Mar 2022

Cepheid Variable Light Curve Analysis On The Embry-Riddle 1-Meter Telescope, Kayla Taylor

Beyond: Undergraduate Research Journal

This report details light curve analysis for four Cepheid variable stars (Polaris, RT Aurigae, RX Aurigae, and Zeta Geminorum) using Embry-Riddle Aeronautical University's 1-meter reflecting telescope and a SBIG-STX 16803 camera with a g filter. Observations were conducted once per week during the Spring 2021 semester; at least one three-hour shift was allotted per week according to the Observational Astronomy Telescope Allocation Committee (TAC). Individual light curves for each target Cepheid were then compared to published data to analyze evidence of evolution on the Instability Strip. Although the light curves showed the sinusoidal nature of brightness oscillations, amplitudes of the …

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Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson Mar 2022

Nine Bright Γ Doradus Variables Discovered With Ground-Based Photometry, Gregory W. Henry, Francis C. Fekel, Michael H. Williamson

Information Systems and Engineering Management Research Publications

We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate γ Doradus (γ Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new γ Dor variables. All exhibit sinusoidal variability with amplitudes between 6 and 65 mmag in Johnson B and periods from 0.28 to 1.13 days. All lie in the same region of the H-R diagram as our previously confirmed γ Dor stars. Of the nine systems, one is a single-lined spectroscopic binary (SB1), two are double-lined spectroscopic binaries (SB2), and …

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The Expres Stellar Signals Project Ii. State Of The Field In Disentangling Photospheric Velocities, Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. De Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo Iii, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak Mar 2022

The Expres Stellar Signals Project Ii. State Of The Field In Disentangling Photospheric Velocities, Lily L. Zhao, Debra A. Fischer, Eric B. Ford, Alex Wise, Michaël Cretignier, Suzanne Aigrain, Oscar Barragan, Megan Bedell, Lars A. Buchhave, João D. Camacho, Heather M. Cegla, Jessi Cisewski-Kehe, Andrew Collier Cameron, Zoe L. De Beurs, Sally Dodson-Robinson, Xavier Dumusque, João P. Faria, Christian Gilbertson, Charlotte Haley, Justin Harrell, David W. Hogg, Parker Holzer, Ancy Anna John, Baptiste Klein, Marina Lafarga, Florian Lienhard, Vinesh Maguire-Rajpaul, Annelies Mortier, Belinda Nicholson, Michael L. Palumbo Iii, Victor Ramirez Delgado, Christopher J. Shallue, Andrew Vanderburg, Pedro T. P. Viana, Jinglin Zhao, Norbert Zicher, Samuel H. C. Cabot, Gregory W. Henry, Rachael M. Roettenbacher, John M. Brewer, Joe Llama, Ryan R. Petersburg, Andrew E. Szymkowiak

Information Systems and Engineering Management Research Publications

Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme-precision radial-velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The Extreme-precision Spectrograph (EXPRES) Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed radial-velocity (RV) correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when …

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Problems Of Formation And Evolution Of Bulges Of Spiral Galaxies, Farkhodjon Botirov, Salakhutdin Nuritdinov Mar 2022

Problems Of Formation And Evolution Of Bulges Of Spiral Galaxies, Farkhodjon Botirov, Salakhutdin Nuritdinov

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this work, we develop the theory of the origin of galactic bulges, and gravitational instability of the bending, as well as modes of perturbation based on the background of a nonlinear non-stationary model. As a result, here, we propose critical diagrams and determine increments of instabilities for such types of perturbations. In addition, we also consider relationships between the masses of the bulge and the central black hole, which is of great importance in studying the evolution of the bulges of spiral galaxies. Moreover, problems on the evolution of bulges in spiral galaxies, together with discussions of their main …

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Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales Mar 2022

Constraints On Dark Photon Dark Matter Using Data From Ligo’S And Virgo’S Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Kagra Collaboration, Tiffany Z. Summerscales

Faculty Publications

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon …

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Computational Data Of Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain, N. Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti Mar 2022

Computational Data Of Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain, N. Dimakis, Sanju Gupta, Razeen Wadud, Muhammad I. Bhatti

Physics and Astronomy Faculty Publications and Presentations

The data presented in this paper refer to the research article "Dry and Hydrated Defective Molybdenum Disulfide/Graphene Bilayer Heterojunction Under Strain for Hydrogen Evolution from Water Splitting: A First-principle Study". Here, we present the Density Functional Theory (DFT) data used to generate optimal geometries and electronic structure for the MoS2/graphene heterostructure under strain, for dry and hydrated pristine and defect configurations. We also report DFT data used to obtain hydrogen Gibbs free energies for adsorption on the MoS2 monolayer and on graphene of the heterostructure. The DFT data were calculated using the periodic DFT code CRYSTAL17, which employs Gaussian basis …

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Spin-Orbit Gravitational Locking - An Effective Potential Approach, Christopher Clouse, Andrea Ferroglia, Miguel C. N. Fiolhais Mar 2022

Spin-Orbit Gravitational Locking - An Effective Potential Approach, Christopher Clouse, Andrea Ferroglia, Miguel C. N. Fiolhais

Publications and Research

The objective of this paper is to study the tidally locked 3:2 spin–orbit resonance of Mercury around the Sun. In order to achieve this goal, the effective potential energy that determines the spinning motion of an ellipsoidal planet around its axis is considered. By studying the rotational potential energy of an ellipsoidal planet orbiting a spherical star on an elliptic orbit with fixed eccentricity and semi-major axis, it is shown that the system presents an infinite number of metastable equilibrium configurations. These states correspond to local minima of the rotational potential energy averaged over an orbit, where the ratio between …

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Measurement Of Structure Dependent Radiative K+ -> E,Sup>(+) Vy Gamma Decays Using Stopped Positive Kaons, H. Ito, A. Kobayashi, S. Bianchin, T. Cao, C. Djalali, D. H. Dongwi, T. Gautam, D. Gill, M. D. Hasinoff, K. Horie, Y. Igarashi, J. Imazato, N. Kalantarians, H. Kawai, S. Kimura, S. Kodama, M. Kohl, H. Lu, O. Mineev, Steffen Strauch, Et. Al. Mar 2022

Measurement Of Structure Dependent Radiative K+ -> E,Sup>(+) Vy Gamma Decays Using Stopped Positive Kaons, H. Ito, A. Kobayashi, S. Bianchin, T. Cao, C. Djalali, D. H. Dongwi, T. Gautam, D. Gill, M. D. Hasinoff, K. Horie, Y. Igarashi, J. Imazato, N. Kalantarians, H. Kawai, S. Kimura, S. Kodama, M. Kohl, H. Lu, O. Mineev, Steffen Strauch, Et. Al.

Faculty Publications

The structure dependent radiative K + → e+νγ (KSD+e2γ) decay was investigated with stopped positive kaons. The e+ momentum spectra containing 574±30 KSD+e2γ events with a K + → μ+ν (Kμ2) background of 28 ± 19 events were measured with and without a photon in coincidence and analyzed with Monte Carlo simulations for acceptance and detector response to extract the ratio of the branching ratio of the KSD+e2γ decay and the K + → e+ν decay including the internal bremsstrahlung process (Ke2(γ )). …

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Oxygen Ion Escape At Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability, Tong Dang, Xuanye Ma, Jiuhou Le, Binzheng Zhang, Tielong Zhang, Zhonghua Yao, John Lyon, Sudong Xiao, Maodong Yan, Oliver Brambles, Kareem Sorathia Mar 2022

Oxygen Ion Escape At Venus Associated With Three-Dimensional Kelvin-Helmholtz Instability, Tong Dang, Xuanye Ma, Jiuhou Le, Binzheng Zhang, Tielong Zhang, Zhonghua Yao, John Lyon, Sudong Xiao, Maodong Yan, Oliver Brambles, Kareem Sorathia

Publications

How oxygens escape from Venus has long been a fundamental but controversial topic in the planetary research. Among various key mechanisms, the Kelvin-Helmholtz instability (KHI) has been suggested to play an important role in the oxygen ion escape from Venus. Limited by either scarce in-situ observations or simplified theoretical estimations, the mystery of oxygen ion escape process associated with KHI is still unsettled. Here we present the first three-dimensional configuration of KHI at Venus with a global multifluid magnetohydrodynamics model, showing a significantly fine structure and evolution of the KHI. KHI mainly occurred at the low latitude boundary layer if …

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Neutron Stars With Baryon Number Violation, Probing Dark Sectors, Jeffrey M. Berryman, Susan Gardner, Mohammadreza Zakeri Mar 2022

Neutron Stars With Baryon Number Violation, Probing Dark Sectors, Jeffrey M. Berryman, Susan Gardner, Mohammadreza Zakeri

Physics and Astronomy Faculty Publications

The neutron lifetime anomaly has been used to motivate the introduction of new physics with hidden-sector particles coupled to baryon number, and on which neutron stars provide powerful constraints. Although the neutron lifetime anomaly may eventually prove to be of mundane origin, we use it as motivation for a broader review of the ways that baryon number violation, be it real or apparent, and dark sectors can intertwine and how neutron star observables, both present and future, can constrain them.

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The Arecibo Observatory As An Instrument For Investigating Orbital Debris: Legacy And Next Generation Performance, James Murray, Fredrick A. Jenet Mar 2022

The Arecibo Observatory As An Instrument For Investigating Orbital Debris: Legacy And Next Generation Performance, James Murray, Fredrick A. Jenet

Physics and Astronomy Faculty Publications and Presentations

In this paper, we investigate the ability of the Arecibo Observatory to characterize the orbital debris environment and compare it to the primary instrument used by NASA's Orbital Debris Program Office, the Haystack Ultra-Wideband Satellite Imaging Radar (HUSIR). Arecibo's location (183 N) increases the percentage of observable orbits (relative to HUSIR) by 27%, which gives Arecibo access to a much larger and previously unmeasured portion of the environment. Due to the recent collapse of the Arecibo dish, in addition to exploring historic capabilities of the Legacy Arecibo Telescope, estimates of the performance of the proposed Next Generation Arecibo Telescope (NGAT) …

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A Multiparameter Degeneracy In Microlensing Events With Extreme Finite Source Effects, Samson A. Johnson, Matthew T. Penny, B. Scott Gaudi Mar 2022

A Multiparameter Degeneracy In Microlensing Events With Extreme Finite Source Effects, Samson A. Johnson, Matthew T. Penny, B. Scott Gaudi

Faculty Publications

For microlenses with sufficiently low mass, the angular radius of the source star can be much larger than the angular Einstein ring radius of the lens. For such extreme finite source effect (EFSE) events, finite source effects dominate throughout the duration of the event. Here, we demonstrate and explore a continuous degeneracy between multiple parameters of such EFSE events. The first component in the degeneracy arises from the fact that the directly observable peak change of the flux depends on both the ratio of the angular source radius to the angular Einstein ring radius and the fraction of the baseline …

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Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vii. Xmm-Newton Observations Of Lensed Quasars, Thomas Connor, Daniel Stern, Alberto Krone-Martins, S. G. Djorgovski, Matthew J. Graham Mar 2022

Gaia Gral: Gaia Dr2 Gravitational Lens Systems. Vii. Xmm-Newton Observations Of Lensed Quasars, Thomas Connor, Daniel Stern, Alberto Krone-Martins, S. G. Djorgovski, Matthew J. Graham

Faculty Publications

We present XMM-Newton X-ray observations of nine confirmed lensed quasars at 1 less than or similar to z less than or similar to 3 identified by the Gaia Gravitational Lens program. Eight systems are strongly detected, with 0.3-8.0 keV fluxes F (0.3-8.0) greater than or similar to 5 x10(-14) erg cm(-2) s(-1). Modeling the X-ray spectra with an absorbed power law, we derive power-law photon indices and 2-10 keV luminosities for the eight detected quasars. In addition to presenting sample properties for larger quasar population studies and for use in planning for future caustic-crossing events, we also identify three quasars …

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A Pair Of Sub-Neptunes Transiting The Bright K-Dwarf Toi-1064 Characterized With Cheops, T. G. Wilson, E. Goffo, Y. Alibert, D. Gandolfi, A. Bonfanti, C. M. Persson, A. Collier Cameron, M. Fridlund, L. Fossati, J. Korth, W. Benz, A. Deline, H.-G. Florén, P. Guterman, V. Adibekyan, M. J. Hooton, S. Hoyer, A. Leleu, A. J. Mustill, S. Salmon, S. G. Sousa, O. Suarez, L. Abe, A. Agabi, R. Alonso, G. Anglada, J. Asquier, T. Bárczy, D. Barrado Navascues, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, N. Billot, X. Bonfils, A. Brandeker, C. Broeg, E. M. Bryant, M. R. Burleigh, M. Buttu, J. Cabrera, S. Charnoz, D. R. Ciardi, R. Cloutier, W. D. Cochran, K. A. Collins, K. D. Colón, N. Crouzet, S. Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. Demangeon, B.-O. Demory, D. Dragomir, G. Dransfield, D. Ehrenreich, A. Erikson, A. Fortier, T. Gan, S. Gill, M. Gillon, C. L. Gnilka, N. Grieves, S. Grziwa, M. Güdel, T. Guillot, J. Haldemann, K. Heng, K. Horne, S. B. Howell, K. G. Isaak, J. M. Jenkins, Eric L.N. Jensen, L. Kiss, G. Lacedelli, K. Lam, J. Laskar, D. W. Latham, A. Lecavelier Des Etangs, M. Lendl, K. V. Lester, A. M. Levine, J. Livingston, C. Lovis, R. Luque, D. Magrin, W. Marie-Sainte, P. F. L. Maxted, A. W. Mayo, B. Mclean, M. Mecina, D. Mékarnia, V. Nascimbeni, L. D. Nielsen, G. Olofsson, H. P. Osborn, H. L. M. Osborne, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, S. Redfield, I. Ribas, G. R. Ricker, M. Rieder, N. C. Santos, G. Scandariato, F.-X. Schmider, R. P. Schwarz, N. J. Scott, S. Seager, D. Ségransan, L. M. Serrano, A. E. Simon, A. M. S. Smith, M. Steller, C. Stockdale, G. Szabó, N. Thomas, E. B. Ting, A. H. M. J. Triaud, S. Udry, V. Van Eylen, V. Van Grootel, R. K. Vanderspek, V. Viotto, N. Walton, J. N. Winn Mar 2022

A Pair Of Sub-Neptunes Transiting The Bright K-Dwarf Toi-1064 Characterized With Cheops, T. G. Wilson, E. Goffo, Y. Alibert, D. Gandolfi, A. Bonfanti, C. M. Persson, A. Collier Cameron, M. Fridlund, L. Fossati, J. Korth, W. Benz, A. Deline, H.-G. Florén, P. Guterman, V. Adibekyan, M. J. Hooton, S. Hoyer, A. Leleu, A. J. Mustill, S. Salmon, S. G. Sousa, O. Suarez, L. Abe, A. Agabi, R. Alonso, G. Anglada, J. Asquier, T. Bárczy, D. Barrado Navascues, S. C. C. Barros, W. Baumjohann, M. Beck, T. Beck, N. Billot, X. Bonfils, A. Brandeker, C. Broeg, E. M. Bryant, M. R. Burleigh, M. Buttu, J. Cabrera, S. Charnoz, D. R. Ciardi, R. Cloutier, W. D. Cochran, K. A. Collins, K. D. Colón, N. Crouzet, S. Csizmadia, M. B. Davies, M. Deleuil, L. Delrez, O. Demangeon, B.-O. Demory, D. Dragomir, G. Dransfield, D. Ehrenreich, A. Erikson, A. Fortier, T. Gan, S. Gill, M. Gillon, C. L. Gnilka, N. Grieves, S. Grziwa, M. Güdel, T. Guillot, J. Haldemann, K. Heng, K. Horne, S. B. Howell, K. G. Isaak, J. M. Jenkins, Eric L.N. Jensen, L. Kiss, G. Lacedelli, K. Lam, J. Laskar, D. W. Latham, A. Lecavelier Des Etangs, M. Lendl, K. V. Lester, A. M. Levine, J. Livingston, C. Lovis, R. Luque, D. Magrin, W. Marie-Sainte, P. F. L. Maxted, A. W. Mayo, B. Mclean, M. Mecina, D. Mékarnia, V. Nascimbeni, L. D. Nielsen, G. Olofsson, H. P. Osborn, H. L. M. Osborne, R. Ottensamer, I. Pagano, E. Pallé, G. Peter, G. Piotto, D. Pollacco, D. Queloz, R. Ragazzoni, N. Rando, H. Rauer, S. Redfield, I. Ribas, G. R. Ricker, M. Rieder, N. C. Santos, G. Scandariato, F.-X. Schmider, R. P. Schwarz, N. J. Scott, S. Seager, D. Ségransan, L. M. Serrano, A. E. Simon, A. M. S. Smith, M. Steller, C. Stockdale, G. Szabó, N. Thomas, E. B. Ting, A. H. M. J. Triaud, S. Udry, V. Van Eylen, V. Van Grootel, R. K. Vanderspek, V. Viotto, N. Walton, J. N. Winn

Physics & Astronomy Faculty Works

We report the discovery and characterization of a pair of sub-Neptunes transiting the bright K-dwarf TOI-1064 (TIC 79748331), initially detected in the Transiting Exoplanet Survey Satellite (TESS) photometry. To characterize the system, we performed and retrieved the CHaracterising ExOPlanets Satellite (CHEOPS), TESS, and ground-based photometry, the High Accuracy Radial velocity Planet Searcher (HARPS) high-resolution spectroscopy, and Gemini speckle imaging. We characterize the host star and determine Teff,* = 4734 ± 67 K, R* = 0.726 ± 0.007 R⊙, and M* = 0.748 ± 0.032 M⊙. We present a …

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Transit Timings Variations In The Three-Planet System: Toi-270, L. Kaye, S. Vissapragada, M. N. Günther, S. Aigrain, T. Mikal-Evans, Eric L.N. Jensen, H. Parviainen, F. J. Pozuelos, L. Abe, J. S. Acton, A. Agabi, D. R. Alves, D. R. Anderson, D. J. Armstrong, K. Barkaoui, O. Barragán, B. Benneke, P. T. Boyd, R. Brahm, I. Bruni, E. M. Bryant, M. R. Burleigh, S. L. Casewell, D. Ciardi, R. Cloutier, K. A. Collins, K. I. Collins, D. M. Conti, I. J. M. Crossfield, N. Crouzet, T. Daylan, D. Dragomir, G. Dransfield, D. Fabrycky, M. Fausnaugh, G. Fuűrész, T. Gan, S. Gill, M. Gillon, M. R. Goad, V. Gorjian, M. Greklek-Mckeon, N. Guerrero, T. Guillot, E. Jehin, J. S. Jenkins, M. Lendl, J. Kamler, S. R. Kane, J. F. Kielkopf, M. Kunimoto, W. Marie-Sainte, J. Mccormac, D. Mékarnia, F. Y. Morales, M. Moyano, E. Palle, V. Parmentier, H. M. Relles, F.-X. Schmider, R. P. Schwarz, S. Seager, A. M. S. Smith, T.-G. Tan, J. Taylor, A. H. M. J. Triaud, J. D. Twicken, S. Udry, J. I. Vines, G. Wang, P. J. Wheatley, J. N. Winn Mar 2022

Transit Timings Variations In The Three-Planet System: Toi-270, L. Kaye, S. Vissapragada, M. N. Günther, S. Aigrain, T. Mikal-Evans, Eric L.N. Jensen, H. Parviainen, F. J. Pozuelos, L. Abe, J. S. Acton, A. Agabi, D. R. Alves, D. R. Anderson, D. J. Armstrong, K. Barkaoui, O. Barragán, B. Benneke, P. T. Boyd, R. Brahm, I. Bruni, E. M. Bryant, M. R. Burleigh, S. L. Casewell, D. Ciardi, R. Cloutier, K. A. Collins, K. I. Collins, D. M. Conti, I. J. M. Crossfield, N. Crouzet, T. Daylan, D. Dragomir, G. Dransfield, D. Fabrycky, M. Fausnaugh, G. Fuűrész, T. Gan, S. Gill, M. Gillon, M. R. Goad, V. Gorjian, M. Greklek-Mckeon, N. Guerrero, T. Guillot, E. Jehin, J. S. Jenkins, M. Lendl, J. Kamler, S. R. Kane, J. F. Kielkopf, M. Kunimoto, W. Marie-Sainte, J. Mccormac, D. Mékarnia, F. Y. Morales, M. Moyano, E. Palle, V. Parmentier, H. M. Relles, F.-X. Schmider, R. P. Schwarz, S. Seager, A. M. S. Smith, T.-G. Tan, J. Taylor, A. H. M. J. Triaud, J. D. Twicken, S. Udry, J. I. Vines, G. Wang, P. J. Wheatley, J. N. Winn

Physics & Astronomy Faculty Works

We present ground- and space-based photometric observations of TOI-270 (L231-32), a system of three transiting planets consisting of one super-Earth and two sub-Neptunes discovered by TESS around a bright (K-mag = 8.25) M3V dwarf. The planets orbit near low-order mean-motion resonances (5:3 and 2:1) and are thus expected to exhibit large transit timing variations (TTVs). Following an extensive observing campaign using eight different observatories between 2018 and 2020, we now report a clear detection of TTVs for planets c and d, with amplitudes of ~10 min and a super-period of ~3 yr, as well as significantly refined estimates of the …

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Search For Intermediate-Mass Black Hole Binaries In The Third Observing Run Of Advanced Ligo And Advanced Virgo, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Wenhui Wang Mar 2022

Search For Intermediate-Mass Black Hole Binaries In The Third Observing Run Of Advanced Ligo And Advanced Virgo, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics and Astronomy Faculty Publications and Presentations

Intermediate-mass black holes (IMBHs) span the approximate mass range 100−105 M⊙, between black holes (BHs) that formed by stellar collapse and the supermassive BHs at the centers of galaxies. Mergers of IMBH binaries are the most energetic gravitational-wave sources accessible by the terrestrial detector network. Searches of the first two observing runs of Advanced LIGO and Advanced Virgo did not yield any significant IMBH binary signals. In the third observing run (O3), the increased network sensitivity enabled the detection of GW190521, a signal consistent with a binary merger of mass ∼150 M⊙ providing direct evidence of …

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