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Articles 1381 - 1410 of 8856

Full-Text Articles in Astrophysics and Astronomy

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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Temporal Scattering, Depolarization, And Persistent Radio Emission From Magnetized Inhomogeneous Environments Near Repeating Fast Radio Burst Sources, Yuan-Pei Yang, Wenbin Lu, Yi Feng, Bing Zhang, Di Li Mar 2022

Temporal Scattering, Depolarization, And Persistent Radio Emission From Magnetized Inhomogeneous Environments Near Repeating Fast Radio Burst Sources, Yuan-Pei Yang, Wenbin Lu, Yi Feng, Bing Zhang, Di Li

Physics & Astronomy Faculty Research

Some repeating fast radio burst (FRB) sources exhibit complex polarization behaviors, including frequencydependent depolarization, variation of rotation measure (RM), and oscillating spectral structures of polarized components. Very recently, Feng et al. reported that active repeaters exhibit conspicuous frequency-dependent depolarization and a strong correlation between RM scatter (σRM) and the temporal scattering time (τs), s s 1.0 0.2, both of which can be well described by multipath propagation through a magnetized inhomogeneous plasma screen. This observation strongly suggests that the temporal scattering and RM scatter originate from the same region. Besides, a particular finding of note in Feng et al. is …

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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, Francisco 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, Francisco Llamas, Soma Mukherjee, Volker Quetschke, Wenhui Wang

Physics & Astronomy 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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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 & Astronomy Faculty Publications

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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Investigating The Future Potential Of An Upgraded Alma To Image Planet-Forming Disks At Sub-Astronomical-Unit Scales, Benjamin P. Burrill, Luca Ricci, Sarah K. Harter, Shangjia Zhang, Zhaohuan Zhu Mar 2022

Investigating The Future Potential Of An Upgraded Alma To Image Planet-Forming Disks At Sub-Astronomical-Unit Scales, Benjamin P. Burrill, Luca Ricci, Sarah K. Harter, Shangjia Zhang, Zhaohuan Zhu

Physics & Astronomy Faculty Research

In recent years, ALMA has been able to observe large-scale substructures within protoplanetary disks. Comparison with the predictions from models of planet–disk interactions has indicated that most of these disk substructures can be explained by the presence of planets with the mass of Neptune or larger at orbital radii of ≈5–100 au. Better resolution is needed to observe structures closer to the star, where terrestrial planets are expected to form, as well as structures opened by planets with masses lower than Neptune. We investigate the capabilities of a possible extension to ALMA that would double the longest baseline lengths in …

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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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Discovery Of Quasi-Periodic Oscillations In The Persistent X-Ray Emission Of Accreting Binary X-Ray Pulsar Lmc X-4, Ketan Rikame, Biswajit Paul, Pragati Pradhan, K.T. Paul Mar 2022

Discovery Of Quasi-Periodic Oscillations In The Persistent X-Ray Emission Of Accreting Binary X-Ray Pulsar Lmc X-4, Ketan Rikame, Biswajit Paul, Pragati Pradhan, K.T. Paul

Publications

We report the discovery of quasi-periodic oscillations (QPOs) in the high-mass X-ray binary (HMXB) pulsar LMC X-4 in its non-flaring (persistent) state using observations with XMM–Newton. In addition to the 74 mHz coherent pulsations, the persistent emission light curve shows a QPO feature in the frequency range of 20–30 mHz. Quasi-periodic flares have been previously observed from LMC X-4 in observations made with Rossi X-ray Timing Explorer (RXTE). However, this is the first time QPOs have been observed in the persistent emission observations of LMC X-4. QPOs in X-ray binaries are generally thought to be related to the rotation of …

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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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Dark Fluxes From Accreting Black Holes Through Several Mechanisms, Rong-Gen Cai, Sichun Sun, Bing Zhang, Yun-Long Zhang Mar 2022

Dark Fluxes From Accreting Black Holes Through Several Mechanisms, Rong-Gen Cai, Sichun Sun, Bing Zhang, Yun-Long Zhang

Physics & Astronomy Faculty Research

We discuss the possibility that accreting black hole systems can be sources for dark matter flux through several different mechanisms. We firstly discuss two types of systems‘: coronal thermal plasmas around supermassive black holes in active galactic nuclei (AGNs), and accretion disks of stellar-mass X-ray black hole binaries (BHBs). We explore how these black hole systems may produce keV light dark matter fluxes and find that the dark fluxes from those sources might be too weak to account for the current XENON1T excess. On the other hand, black holes can be good accelerators to accrete and boost heavy dark matter …

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The Effect Of Adiabatic Compression On Dark Matter Halos And The Radial Acceleration Relation, Pengfei Li, Stacy S. Mcgaugh Mar 2022

The Effect Of Adiabatic Compression On Dark Matter Halos And The Radial Acceleration Relation, Pengfei Li, Stacy S. Mcgaugh

Faculty Scholarship

We use a semiempirical model to investigate the radial acceleration relation (RAR) in a cold dark matter (CDM) framework. Specifically, we build 80 model galaxies covering the same parameter space as the observed galaxies in the SPARC database, assigning them to dark matter (DM) halos using abundance-matching and halo mass-concentration relations. We consider several abundance-matching relations, finding some to be a better match to the kinematic data than others. We compute the unavoidable gravitational interactions between baryons and their DM halos, leading to an overall compression of the original Navarro-Frenk-White (NFW) halos. Before halo compression, high-mass galaxies lie approximately on …

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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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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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Low Exposure Long-Baseline Neutrino Oscillation Sensitivity Of The Dune Experiment, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, B. Aimard, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monnsalve, M. Alrashed, C. Alt, A. Alton, P. Amedo, J. Anderson, C. Andreopooulos, M. Andreotti, M. P. Andrews, F. Andrianala, S. Andringa, N. Anfimov, Roberto Petti, Sanjib R. Mishra Ph.D., Et. Al. Mar 2022

Low Exposure Long-Baseline Neutrino Oscillation Sensitivity Of The Dune Experiment, A. Aduszkiewicz, J. Aguilar, Z. Ahmad, B. Aimard, B. Ali-Mohammadzadeh, T. Alion, K. Allison, S. Alonso Monnsalve, M. Alrashed, C. Alt, A. Alton, P. Amedo, J. Anderson, C. Andreopooulos, M. Andreotti, M. P. Andrews, F. Andrianala, S. Andringa, N. Anfimov, Roberto Petti, Sanjib R. Mishra Ph.D., Et. Al.

Faculty Publications

The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE’s sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-calendar years (kt-MW-CY), where calendar years include an assumption of 57% accelerator uptime based on past accelerator performance at Fermilab. The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 4⁢𝜎 (5⁢𝜎) …

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

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

Physics & Astronomy Faculty Publications

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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Circumbinary Disk Evolution In The Presence Of An Outer Companion Star, Rebecca G. Marin, Stephen Lepp, Stephen H. Lubow, Matthew A. Kenworthy, Grant M. Kennedy, David Vallet Mar 2022

Circumbinary Disk Evolution In The Presence Of An Outer Companion Star, Rebecca G. Marin, Stephen Lepp, Stephen H. Lubow, Matthew A. Kenworthy, Grant M. Kennedy, David Vallet

Physics & Astronomy Faculty Research

We consider a hierarchical triple system consisting of an inner eccentric binary with an outer companion. A highly misaligned circumbinary disk around the inner binary is subject to two competing effects: (i) nodal precession about the inner binary eccentricity vector that leads to an increase in misalignment (polar alignment) and (ii) Kozai–Lidov (KL) oscillations of eccentricity and inclination driven by the outer companion that leads to a reduction in the misalignment. The outcome depends upon the ratio of the timescales of these effects. If the inner binary torque dominates, then the disk aligns to a polar orientation. If the outer …

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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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Macroscale Robust Superlubricity On Metallic Nbb2, Jia Wang, Chang Liu, Kaifei Miao, Kan Zhang, Weitao Zheng, Changfeng Chen Mar 2022

Macroscale Robust Superlubricity On Metallic Nbb2, Jia Wang, Chang Liu, Kaifei Miao, Kan Zhang, Weitao Zheng, Changfeng Chen

Physics & Astronomy Faculty Research

Robust superlubricity (RSL), defined by concurrent superlow friction and wear, holds great promise for reducing material and energy loss in vast industrial and technological operations. Despite recent advances, challenges remain in finding materials that exhibit RSL on macrolength and time scales and possess vigorous electrical conduction ability. Here, the discovery of RSL is reported on hydrated NbB2 films that exhibit vanishingly small coefficient of friction (0.001–0.006) and superlow wear rate (≈10−17 m3 N−1 m−1) on large length scales reaching millimeter range and prolonged time scales lasting through extensive loading durations. Moreover, the measured low resistivity (≈10−6 Ω m) of the …

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Accreting On The Edge: A Luminosity-Dependent Cyclotron Line In The Be/X-Ray Binary 2s 1553-542 Accompanied By Accretion Regimes Transition, C. Malacaria, Y. Bhargava, Joel B. Coley, L. Ducci, Pragati Pradhan, R. Ballhausen, F. Fuerst, N. Islam, G. K. Jaisawal, P. Jenke, P. Kretschmar, I. Kreykenbohm, K. Pottschmidt, E. Sokolova-Lapa, R. Staubert, J. Wilms, C.A. Wilson-Hodge, Michael T. Wolff Mar 2022

Accreting On The Edge: A Luminosity-Dependent Cyclotron Line In The Be/X-Ray Binary 2s 1553-542 Accompanied By Accretion Regimes Transition, C. Malacaria, Y. Bhargava, Joel B. Coley, L. Ducci, Pragati Pradhan, R. Ballhausen, F. Fuerst, N. Islam, G. K. Jaisawal, P. Jenke, P. Kretschmar, I. Kreykenbohm, K. Pottschmidt, E. Sokolova-Lapa, R. Staubert, J. Wilms, C.A. Wilson-Hodge, Michael T. Wolff

Publications

Accreting X-ray pulsars undergo luminous X-ray outbursts during which the luminosity-dependent spectral and timing features of the neutron star’s emission can be analyzed in detail, thus shedding light on the accretion regime at work. We took advantage of a monitoring campaign that was performed with NuSTAR, Swift/XRT, AstroSat and NICER to follow the Be/X-ray Binary 2S 1553-542 along one of its rare outbursts, and thus trace its spectral and timing evolution. We report the discovery of a luminosity-dependent cyclotron line energy for the first time in this source. The pulse profiles and pulsed fraction also show variability along the outburst, …

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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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Stellar Mass-To-Light Ratios: Composite Bulge+Disk Models And The Baryonic Tully-Fisher Relation, Stacy S. Mcgaugh Mar 2022

Stellar Mass-To-Light Ratios: Composite Bulge+Disk Models And The Baryonic Tully-Fisher Relation, Stacy S. Mcgaugh

Faculty Scholarship

We present stellar population models to calculate the mass-to-light ratio (Γ∗) based on galaxies' colors ranging from GALEX far-UV to Spitzer IRAC1 at 3.6 μm. We present a new composite bulge+disk Γ∗ model that considers the varying contribution from bulges and disks based on their optical and near-IR colors. Using these colors, we build plausible star formation histories and chemical enrichment scenarios based on the star formation rate-stellar mass and mass-metallicity correlations for star-forming galaxies. The most accurate prescription is to use the actual colors for the bulge and disk components to constrain Γ∗; however, a reasonable bulge+disk model plus …

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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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Misalignment Of Terrestrial Circumbinary Planets As An Indicator Of Their Formation Mechanism, Anna C. Childs, Rebecca G. Martin Mar 2022

Misalignment Of Terrestrial Circumbinary Planets As An Indicator Of Their Formation Mechanism, Anna C. Childs, Rebecca G. Martin

Physics & Astronomy Faculty Research

Circumbinary gas disks are often observed to be misaligned with the binary orbit, suggesting that planet formation may proceed in a misaligned disk. With n-body simulations, we consider the formation of circumbinary terrestrial planets from a particle disk that is initially misaligned. We find that if terrestrial planets form in this way, in the absence of gas, they can only form close to coplanar or close to polar to the binary orbit. Planets around a circular binary form coplanar while planets around an eccentric binary can form coplanar or polar depending on the initial disk misalignment and the binary eccentricity. …

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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 & Astronomy Faculty Publications

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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Testing The Reliability Of X-Rays As A Tool For Constraining Mass-Loss Rates Of Hot Stars, Sean J. Gunderson, Kenneth G. Gayley, Pragati Pradhan, David P. Huenemoerder, Nathan A. Miller Mar 2022

Testing The Reliability Of X-Rays As A Tool For Constraining Mass-Loss Rates Of Hot Stars, Sean J. Gunderson, Kenneth G. Gayley, Pragati Pradhan, David P. Huenemoerder, Nathan A. Miller

Publications

We fit a new line shape model to Chandra X-ray spectra of the O supergiant ζ Puppis to test the robustness of mass-loss rates derived from X-ray wind line profiles against different assumed heating models. Our goal is to track the hot gas by replacing the common assumption that it is proportional to the cool gas emission measure. Instead of assuming a turn-on radius for the hot gas (as appropriate for the line-deshadowing instability internal to the wind), we parametrize the hot gas in terms of a mean-free path for accelerated low-density gas to encounter slower high-density material. This alternative …

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Ultra-Broadband Bending Beam And Bottle Beam Based On Acoustic Metamaterials, Xudong Fan, Xiaolong Huang, Yang Kang, Can Li, Ning Li, Chunsheng Weng, Likun Zhang Mar 2022

Ultra-Broadband Bending Beam And Bottle Beam Based On Acoustic Metamaterials, Xudong Fan, Xiaolong Huang, Yang Kang, Can Li, Ning Li, Chunsheng Weng, Likun Zhang

Faculty and Student Publications

We report the realization of an ultra-broadband bending beam based on acoustic meta-materials by the theoretical prediction and the numerical validation. The proposed structure is composed of a series of straight tubes with spatially modulated depths. We analytically derive the depth profile required for the generation of an ultra-broadband bending beam, and examine the performance of the metastructure numerically. The design is then extended for the generation of a three-dimensional bottle beam. The transverse trapping behaviours on small rigid objects by the bottle beam are investigated based on the force potential. Our work will help the further study of broadband …

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Search For B0 Meson Decays Into Λ And Missing Energy With A Hadronic Tagging Method At Belle, C. Hadjivasiliou, B. G. Fulsom, J. F. Strube, I. Adachi, H. Aihara, D. M. Asner, H. Atmacan, T. Aushev, V. Babu, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, D. Bodrov, J. Borah, A. Bozek Mar 2022

Search For B0 Meson Decays Into Λ And Missing Energy With A Hadronic Tagging Method At Belle, C. Hadjivasiliou, B. G. Fulsom, J. F. Strube, I. Adachi, H. Aihara, D. M. Asner, H. Atmacan, T. Aushev, V. Babu, K. Belous, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, D. Bodrov, J. Borah, A. Bozek

Faculty and Student Publications

We present a search for the decays of B0 mesons into a final state containing a Λ baryon and missing energy. These results are obtained from a 711 fb-1 data sample that contains 772×106 BB¯ pairs and was collected near the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode and require the remainder of the event to consist of only a single Λ. No evidence for these decays is found, and we set 90% confidence level upper limits on the …

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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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