Astrophysics and Astronomy Commons^™

Photolysis And Sublimation Chemistry Of Ammonium Cyanide With Relevance To Cometary Environments, O. H. Wilkins, K. M. Yocum, Vincent J. Esposito, E. Harel, S. N. Milam, P. A. Gerakines

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bulk nitrogen is depleted in solar system objects, including the terrestrial planets, chondritic meteorites, and comets. Recently, it was suggested that cometary nitrogen may be locked up in ammonium salts—ionic solids comprising ammonia (NH₃) and an acid such as hydrogen cyanide (HCN)—based on Rosetta/ROSINA data from comet 67P/Churyumov–Gerasimanko. Among the proposed salts to have been found in 67P were ammonium cyanide (NH₄CN) and ammonium cyanate (NH₄OCN), which were inferred from identifying HCN, cyanamide (NH₂CN), and isocyanic acid (HNCO) in the mass spectrometry data collected in the coma of 67P. However, the relationship …

Spatial And Spectral Characterization Of The Gravitational-Wave Background With The Pta Optimal Statistic, Kyle A. Gersbach, Stephen R. Taylor, Patrick M. Meyers, Joseph D. Romano

Physics & Astronomy Faculty Publications

Pulsar timing arrays (PTAs) have made tremendous progress and are now showing strong evidence for the gravitational-wave background (GWB). Further probing the origin and characteristics of the GWB will require more generalized analysis techniques. Bayesian methods are most often used but can be computationally expensive. On the other hand, frequentist methods, like the PTA optimal statistic (OS), are more computationally efficient and can produce results that are complementary to Bayesian methods, allowing for stronger statistical cases to be built from a confluence of different approaches. In this work we expand the capabilities of the OS through a technique we call …

Rapid Mid-Infrared Spectral Timing With Jwst: Grs 1915+105 During An Mir-Bright And X-Ray-Obscured State, P. Gandhi, E.S. Borowski, J. Byrom, R.I. Hynes, T.J. Maccarone, A.W. Shaw, O.K. Adegoke, D. Altamirano, M.C. Baglio, Y. Bhargava, C.T. Britt, D.A.H. Buckley, D.J.K. Buisson, P. Casella, N. Castro Segura, P.A. Charles, J.M. Corral-Santana, V.S. Dhillon, R. Fender, A. Gurpide, C.O. Heinke, A.B. Igl, C. Knigge, S. Markoff, G. Mastroserio, M.L. Mccollough, M. Middleton, J.M. Miller, J.C.A. Miller-Jones, S.E. Motta, J.A. Paice, D.D. Pawar, R.M. Plotkin, P. Pradhan, M.E. Ressler, D.M. Russell, T.D. Russell, P. Santos-Sanz, T. Shahbaz, T. Shahbaz, G.R. Sivakoff, D. Steeghs, A.J. Tetarenko, J.A. Tomsick, F.M. Vincentelli, M. George, M. Gurwell, R. Rao

Publications

No abstract provided.

Elastomeric Nanocomposite With Solvent-Free, One Step, In Situ Shear Exfoliation Of Graphite To Graphene, Ashiqur Rahman, Md Abdur Rahman Bin Abdus Salam, Matthew G. Boebinger, Ahmed Touhami, Jennifer Lynch, Ali Ashraf

Physics & Astronomy Faculty Publications

A graphene nanoflake (GNF)-enhanced elastomeric nanocomposite (G-EMC) is fabricated following an innovative, cost-effective, single-step, in situ shear exfoliation (ISE) method from low-cost bulk material, graphite, where uniform mixing happens simultaneously within the elastomer matrix. Electron microscopy, atomic force microscopy, and photo-induced force microscopy results show good dispersion of GNFs with exfoliation to a few layers and uniform distribution in the elastomer matrix. X-ray photoelectron spectroscopy analysis shows less than 1% oxygen-containing functional groups/impurity, enhanced bonding through the formation of edge sites as fracture occurs across the GNF basal plane, and pi-pi interactions with newly exfoliated planar basal plane surfaces of …

A Second Candidate Magnetic Helium Core White Dwarf And 3 Other Variable White Dwarfs In The Globular Cluster Ngc 6397, Manuel Pichardo Marcano, Liliana E. Rivera Sandoval, Thomas J. Maccarone, Rene D. Rohrmann, Leandro G. Althaus, Craig O. Heinke, Diogo Belloni, Arash Bahramian

Physics & Astronomy Faculty Publications

Using archival Hubble Space Telescope observations, we report the discovery of four variable low-mass white dwarfs (WDs; 0.18 M⊙ ≤ M ≤ 0.5 M⊙) in the globular cluster NGC 6397. One source exhibits a periodic optical modulation of 5.21 ± 0.02 hr, which we interpret as potentially due to the rotation of a magnetic helium core WD (He WD). This makes this candidate the second magnetic He WD in NGC 6397, and one of the few He WDs with a measured rotation period. The other three candidates show aperiodic variability, with a change in magnitude ranging from ∼0.11 …

Energy Dependence Of Polarized Γγ → E+E− In Peripheral Au + Au Collisions At √Snn = 54.4 And 200 Gev With The Star Experiment At Rhic, Star Collaboration

Physics and Astronomy Faculty Publications

We report the differential yields at mid-rapidity of the Breit-Wheeler process (γ γ → e+e−) in peripheral Au + Au collisions at √s NN = 54.4 and 200 GeV with the STAR experiment at the Relativistic Heavy Ion Collider (RHIC), as a function of energy √s NN , e+e− transverse momentum pT , p2 T , invariant mass Mee, and azimuthal angle. In the invariant mass range of 0.4 < Mee < 2.6 GeV/c2 at low transverse momentum (pT < 0.15 GeV/c), the yields increase while the pair √〈p2 T〉 decreases with increasing √s NN , a feature that is correctly predicted by the QED calculation. The energy dependencies of the measured quantities are sensitive to the nuclear form factor, infrared divergence and photon polarization. The data are compiled and used to extract the charge radius of the Au nucleus.

Clea Labs For Stellar And Cosmological Astronomy Bottled For Silicon Macintosh, Hansika Reddy Bandela, Yuktha Shetty, Jack C. Straton

Physics Faculty Publications and Presentations

Project CLEA -- CONTEMPORARY LABORATORY EXPERIENCES IN ASTRONOMY -- develops laboratory exercises that illustrate modern astronomical techniques using digital data and color images.

These Labs were developed for Windows, but the authors have bottled them for Silicon Macintosh computers.

Clea Labs For Planetary, Stellar, And Cosmological Astronomy Configured For 64-Bit Windows 11+ Machines, Itan Altamirano, Jack C. Straton

Physics Faculty Publications and Presentations

Project CLEA -- CONTEMPORARY LABORATORY EXPERIENCES IN ASTRONOMY -- develops laboratory exercises that illustrate modern astronomical techniques using digital data and color images.

These Labs were developed for 32-bit Windows machines but PSU student Itan Altamirano reconfigured installation programs to bypass steps that ask for DVDs and allowing these 32-bit programs to work on 64-bit Windows 11+ computers.

Sites Of Planet Formation In Binary Systems. Ii. Double The Disks In Df Tau, T. Kutra, B. M. Tofflemire, R. Akeson, G. H. Schaefer, S.-Y. Tang, D. Segura-Cox, C. M. Johns-Krull, A. Kraus, S. Andrews, Eric L.N. Jensen

Physics & Astronomy Faculty Works

This article presents the latest results of our Atacama Large Millimeter/submillimeter Array (ALMA) program to study circumstellar disk characteristics as a function of orbital and stellar properties in a sample of young binary star systems known to host at least one disk. Optical and infrared observations of the eccentric, ∼48 yr period binary DF Tau indicated the presence of only one disk around the brighter component. However, our 1.3 mm ALMA thermal continuum maps show two nearly equal-brightness components in this system. We present these observations within the context of updated stellar and orbital properties, which indicate that the inner …

Neutron Star Low-Mass X-Ray Binaries In And Out Of Focus: Nustar Stray Light, Songwei Li

Wayne State University Dissertations

Neutron star low-mass X-ray binaries (NS LMXBs) provide crucial insights into the physics of accretion under extreme gravity. In this dissertation, we explore the capabilities of NuSTAR’s stray light (SL) observations to supplement, and in some cases, surpass focused data in spectral studies of bright LMXBs. Utilizing the use of SL datasets, we perform detailed spectral analyses of two Z sources: GX 340+0 and Sco X-1.

For GX 340+0, we compare 7 focused and 25 SL observations across multiple spectral states, demonstrating that SL data significantly expand temporal coverage and allow for the detection of long-term spectral evolution not evident …

The Presence Of Outer Giant Planets And Their Role In Inner Planet Formation With And Without Their Influence, Mateo E. Guerra Toro

Graduate Theses/Dissertations

We performed dynamical simulations of the giant impact phase of planet formation to investigate the formation of inner terrestrial planets under the influence of 4 solar system-like outer giant planets. We developed a new code using the N-body simulation suite REBOUND and REBOUNDx (Rein et al. (2019) and Tamayo et al. (2019)) to simulate 2 stages of planetary formation: a residual gaseous protoplanetary disk phase and subsequent dynamical evolution after the disk photoevaporates. The initial conditions for the inner planetary embryos were taken by Morrison et al. (2020) based on a range of solid surface densities that produced Super-Earth terrestrial …

Range Safety And Design For Launch, Space Dynamics Laboratory

Space Dynamics Laboratory Publications

Design to make licensing and launch easy

• Sometimes the most innovative or elegant solution isn’t the best one
• The less you have to prove, the better
• Don’t use novel materials
• Don’t use novel methods

Example: 3D printing is cool and reduces part count because you can design otherwise unmachinable parts

• Now you have to test, analyze, and prove to everyone that your part won’t fail
• If you machined the parts from AL 6061-T6 and bolted them together with stainless steel fasteners, nobody would have looked twice

Dual View Of The Z2-Gauged Xy Model In 3d, Piers Coleman, Anatoly Kuklov, Alexei Tsvelik

Publications and Research

The Z₂ gauged XY model is of long-standing interest both in the context of nematic order, and the study of fractionalization and superconductivity. This paper presents heuristic arguments that no deconfinement of the XY field occurs in this model and presents results of a large-scale Monte Carlo simulations on a cubic lattice which are consistent with this conclusion. The correlation radius determining the confinement is found to be growing rapidly as a function of the parameters in the phase featuring the nematic order. Thus, mesoscopic properties of the system can mimic deconfinement with high accuracy in some part of …

Quantifying And Understanding The Role Of Bias In Astrophysical Data, Joshua A. Osborne

Physics Dissertations - Archive

Astrophysical studies are limited to the data provided. Data which is inherently prone to a range of biases such as: instrumental, selection, and methodological bias. Quantifying these biases and understanding their origin is critical to ensuring that the results we infer are representative of the physical world.

This is true even when attempting to study high-redshift phenomena, such as Gamma Ray Bursts (GRBs). Due to their immense brightness at high redshifts, GRBs serve as a strong candidate for standard candles in high redshift space. Their use as a standard candle, however, requires a precise understanding of observational biases that affect …

Measurement Of Two-Point Energy Correlators Within Jets In P+P Collisions At Sqrt[S]=200  Gev, Star Collaboration

Physics and Astronomy Faculty Publications

Hard-scattered partons ejected from high-energy proton-proton collisions undergo parton shower and hadronization, resulting in collimated collections of particles that are clustered into jets. A substructure observable that highlights the transition between the perturbative and nonperturbative regimes of jet evolution in terms of the angle between two particles is the two-point energy correlator (EEC). In this Letter, the first measurement of the EEC at RHIC is presented, using data taken from 200 GeV p þ p collisions by the STAR experiment. The EEC is measured both for all the pairs of particles in jets and separately for pairs with like and …

Design Of The Ecce Detector For The Electron Ion Collider, J. K. Adkins

Physics and Astronomy Faculty Publications

The EIC Comprehensive Chromodynamics Experiment (ECCE) detector has been designed to address the full scope of the proposed Electron Ion Collider (EIC) physics program as presented by the National Academy of Science and provide a deeper understanding of the quark–gluon structure of matter. To accomplish this, the ECCE detector offers nearly acceptance and energy coverage along with excellent tracking and particle identification. The ECCE detector was designed to be built within the budget envelope set out by the EIC project while simultaneously managing cost and schedule risks. This detector concept has been selected to be the basis for the EIC …

Evaluation Of The Stability Of Argan Oil Nanoemulsions Formulated And Optimized Through Experimental Design For Dermatological Applications, Yousra Mdarhri, Ikram Bouziane, Narjisse Mokhtari, Lama Rissouli, Ahmed Touhami, Fakhita Touhami, Mohamed Chabbi

Physics & Astronomy Faculty Publications

Argan oil is a highly sought-after natural product renowned for its therapeutic and rejuvenating properties. This study focused on harnessing its dermatological bioactivity by developing stable nanoemulsions through a simple low-energy method using a single non-ionic surfactant. The composition and properties of Argan oil were analyzed using High-Performance Liquid Chromatography (HPLC), Gas Chromatography (GC), and quality indexes, adhering to international standards. The effect of system composition on stability was evaluated using a pseudo-ternary phase diagram and Phase Inversion Composition (PIC) emulsification technique. Optimal process parameters for producing stable nanoemulsion were determined through Response Surface Methodology (RSM) analysis. The resulting nanoemulsions …

The Gaps Programme At Tng: Lxv. Precise Density Measurement Of Toi-1430 B, A Young Planet With An Evaporating Atmosphere, D. Nardiello, J. M. Akana Murphy, R. Spinelli, M. Baratella, S. Desidera, V. Nascimbeni, L. Malavolta, K. Biazzo, A. Maggio, Ryan J. Oelkers

Physics & Astronomy Faculty Publications

Context. Small-sized (< 4 R_⊕) exoplanets in tight orbits around young stars (10–1000 Myr) give us the opportunity to investigate the mechanisms that led to their formation, the evolution of their physical and orbital properties, and, in particular, their atmospheres. Thanks to the all-sky survey carried out by the TESS spacecraft, many of these exoplanets have been discovered, and have subsequently been characterized with dedicated follow-up observations.

Aims. In the context of a collaboration among the Global Architecture of Planetary Systems (GAPS) team, the TESS-Keck Survey (TKS) team, and the California Planet Search (CPS) team, we measured …

Line List For The A²Π−X²Σ⁺ And The B²Σ⁺−X²Σ⁺ Band Systems Of Caf, Léo Lavy, Peter F. Bernath, Adam Pastorek

Chemistry & Biochemistry Faculty Publications

The spectral analysis of molecule-rich asymptotic giant branch (AGB) stars is challenging. Although other calcium and fluorine bearing molecules are observed in the microwave and in the visible spectrum of AGB stars, CaF has never been detected, despite favorable chemical equilibrium predictions. Yet, measuring the CaF abundance could give more insight into the fluorine budget of AGB stars and allow better simulation of stellar spectra. In this work, we present an analysis of the visible spectrum of CaF obtained with a Fourier transform spectrometer. CaF A²Π−X²Σ⁺ and B²Σ⁺−X²Σ⁺ band systems were excited with a hollow cathode discharge. Using previous fluorescence …

Collision-Induced Absorption Spectra Of N₂ And Ch₄, Ryan M. Johnson, Peter F. Bernath, Brant Billinghurst, Jianbao Zhao

Chemistry & Biochemistry Faculty Publications

Collision-induced spectra are essential for radiative transfer modeling of Titan's atmosphere. We present experimental spectra of nitrogen–methane mixtures with an accompanying fit of N₂-CH₄ collision-induced absorption in the 30–400 cm⁻¹ region at about 130 K. We found a peak absorption of 2.30 × 10⁻⁵ cm⁻¹ amagat⁻² at 75 cm⁻¹ and a secondary peak of 1.35 × 10⁻⁵ c⁻¹ amagat⁻² at 206.5 cm⁻¹, which agrees with previous studies. Our work does not support the suggestion that N₂-CH₄ CIA in the far-infrared should be increased by about 50%, as suggested by spectroscopic modeling of Titan using data from A. Borysow & C. …