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Articles 1471 - 1500 of 8856

Full-Text Articles in Astrophysics and Astronomy

A New Universal Polarization Resolving Software Package For Solar Coronal And Heliospheric Observations, Bryce M. Walbridge, Matthew J. West, J. Marcus Hughes, Dan Seaton, Chris Lowder Jan 2022

A New Universal Polarization Resolving Software Package For Solar Coronal And Heliospheric Observations, Bryce M. Walbridge, Matthew J. West, J. Marcus Hughes, Dan Seaton, Chris Lowder

Summer Research

No abstract provided.

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Measurement Of B (Bs →Dsx) With Bs Semileptonic Tagging, B. Wang, K. Kinoshita, H. Aihara, D. M. Asner, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, P. Behera, C. Beleño, J. Bennett, M. Bessner, V. Bhardwaj, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek Jan 2022

Measurement Of B (Bs →Dsx) With Bs Semileptonic Tagging, B. Wang, K. Kinoshita, H. Aihara, D. M. Asner, T. Aushev, R. Ayad, V. Babu, I. Badhrees, A. M. Bakich, P. Behera, C. Beleño, J. Bennett, M. Bessner, V. Bhardwaj, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek

Faculty and Student Publications

We report the first direct measurement of the inclusive branching fraction B(Bs→DsX) via Bs tagging in e+e-→ (5S) events. Tagging is accomplished through a partial reconstruction of semileptonic decays Bs→DsXℓν, where X denotes unreconstructed additional hadrons or photons and ℓ is an electron or muon. With 121.4 fb-1 of data collected at the (5S) resonance by the Belle detector at the KEKB asymmetric-energy e+e- collider, we obtain B(Bs→DsX)=(60.2±5.8±2.3)%, where the first uncertainty is statistical and the second is systematic.

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Toi-2257 B: A Highly Eccentric Long-Period Sub-Neptune Transiting A Nearby M Dwarf, N. Schanche, F. J. Pozuelos, M. N. Günther, R. D. Wells, A. J. Burgasser, P. Chinchilla, L. Delrez, E. Ducrot, L. J. Garcia, Y. Gómez Maqueo Chew, E. Jofré, B. V. Rackham, D. Sebastian, K. G. Stassun, D. Stern, M. Timmermans, K. Barkaoui, A. Belinski, Z. Benkhaldoun, W. Benz, A. Bieryla, F. Bouchy, A. Burdanov, D. Charbonneau, J. L. Christiansen, K. A. Collins, B.-O. Demory, M. Dévora-Pajares, J. De Wit, D. Dragomir, G. Dransfield, E. Furlan, M. Ghachoui, M. Gillon, C. Gnilka, M. A. Gómez-Muñoz, N. Guerrero, M. Harris, K. Heng, C. E. Henze, K. Hesse, S. B. Howell, E. Jehin, J. Jenkins, Eric L.N. Jensen, M. Kunimoto, D. W. Latham, K. Lester, K. K. Mcleod, I. Mireles, C. A. Murray, P. Niraula, P. P. Pedersen, D. Queloz, E. V. Quintana, G. Ricker, A. Rudat, L. Sabin, B. Safonov, U. Schroffenegger, N. Scott, S. Seager, I. Strakhov, A. H. M. J. Triaud, R. Vanderspek, M. Vezie, J. Winn Jan 2022

Toi-2257 B: A Highly Eccentric Long-Period Sub-Neptune Transiting A Nearby M Dwarf, N. Schanche, F. J. Pozuelos, M. N. Günther, R. D. Wells, A. J. Burgasser, P. Chinchilla, L. Delrez, E. Ducrot, L. J. Garcia, Y. Gómez Maqueo Chew, E. Jofré, B. V. Rackham, D. Sebastian, K. G. Stassun, D. Stern, M. Timmermans, K. Barkaoui, A. Belinski, Z. Benkhaldoun, W. Benz, A. Bieryla, F. Bouchy, A. Burdanov, D. Charbonneau, J. L. Christiansen, K. A. Collins, B.-O. Demory, M. Dévora-Pajares, J. De Wit, D. Dragomir, G. Dransfield, E. Furlan, M. Ghachoui, M. Gillon, C. Gnilka, M. A. Gómez-Muñoz, N. Guerrero, M. Harris, K. Heng, C. E. Henze, K. Hesse, S. B. Howell, E. Jehin, J. Jenkins, Eric L.N. Jensen, M. Kunimoto, D. W. Latham, K. Lester, K. K. Mcleod, I. Mireles, C. A. Murray, P. Niraula, P. P. Pedersen, D. Queloz, E. V. Quintana, G. Ricker, A. Rudat, L. Sabin, B. Safonov, U. Schroffenegger, N. Scott, S. Seager, I. Strakhov, A. H. M. J. Triaud, R. Vanderspek, M. Vezie, J. Winn

Physics & Astronomy Faculty Works

Context. Thanks to the relative ease of finding and characterizing small planets around M-dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs makes such objects particularly compelling as they provide clues about the formation and evolution of these systems. Aims. In this study we present the discovery of TOI-2257 b (TIC 198485881), a long-period (35 d) sub-Neptune orbiting an M3 star at 57.8 pc. Its transit depth is about 0.4%, large enough to be detected with medium-size, ground-based telescopes. The long transit duration …

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Extremely Broad Ly Α Line Emission From The Molecular Intragroup Medium In Stephan's Quintet: Evidence For A Turbulent Cascade In A Highly Clumpy Multiphase Medium?, P. Guillard, P. N. Appleton, F. Boulanger, J. M. Shull, M. D. Lehnert, G. Pineau Des Forets, E. Falgarone, M. E. Cluver, C. K. Xu, Sarah C. Gallagher, P. A. Duc Jan 2022

Extremely Broad Ly Α Line Emission From The Molecular Intragroup Medium In Stephan's Quintet: Evidence For A Turbulent Cascade In A Highly Clumpy Multiphase Medium?, P. Guillard, P. N. Appleton, F. Boulanger, J. M. Shull, M. D. Lehnert, G. Pineau Des Forets, E. Falgarone, M. E. Cluver, C. K. Xu, Sarah C. Gallagher, P. A. Duc

Physics and Astronomy Publications

We present Hubble Space Telescope Cosmic Origin Spectrograph (COS) UV line spectroscopy and integral-field unit (IFU) observations of the intragroup medium in Stephan's Quintet (SQ). SQ hosts a 30 kpc long shocked ridge triggered by a galaxy collision at a relative velocity of 1000 km s-1, where large amounts of molecular gas coexist with a hot, X-ray-emitting, plasma. COS spectroscopy at five positions sampling the diverse environments of the SQ intragroup medium reveals very broad (≈2000 km s-1) Lyα line emission with complex line shapes. The Lyα line profiles are similar to or much broader than those of Hβ, [C …

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What's New In Differentialgeometry Release Dg2022, Ian M. Anderson, Charles G. Torre Jan 2022

What's New In Differentialgeometry Release Dg2022, Ian M. Anderson, Charles G. Torre

Tutorials on... in 1 hour or less

This Maple worksheet demonstrates the salient new features and functionalities of the 2022 release of the DifferentialGeometry software package.

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Formation Of Contact Binary Stars: 1) Kozai Cycles With Tidal Friction, Levi Carr, Lau Jenn Feng, Larry A. Molnar Jan 2022

Formation Of Contact Binary Stars: 1) Kozai Cycles With Tidal Friction, Levi Carr, Lau Jenn Feng, Larry A. Molnar

Summer Research

A binary star is a system that contains two stars orbiting each other. A contact binary is a binary star whose component stars are so close that they share the same atmosphere (see Figure 1 on far right). They are the most common kind of eclipsing binary stars. Critical questions to be answered are: how do they form, how do they survive for a long time, and how do they ultimately die? This summer’s work focused on the first of those questions. A process is needed to bring a widely separated binary into contact. It has been suggested this requires …

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Physical Characteristics And Classification Of The Large Amplitude Variable Star V1719 Cygni, Ashley Lieber, Logan Siems, Julia Kennefick, Michael Fitzgerald Jan 2022

Physical Characteristics And Classification Of The Large Amplitude Variable Star V1719 Cygni, Ashley Lieber, Logan Siems, Julia Kennefick, Michael Fitzgerald

Inquiry: The University of Arkansas Undergraduate Research Journal

Pulsating stars are used as standard candles which are helpful in determining distances to stellar objects along with the relationship between their period and apparent luminosity. The focus of this study was the variable star, V1719 Cygni, which is often classified as a Delta (δ) Scuti star, but there exists debate that it should be classified as a RR Lyrae star due to its abnormal light curve and similar characteristics between the two variable star categories. Observational data was taken in 2019 using the Las Cumbres Observatory international telescope network. The resulting data were calibrated using comparison stars in the …

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Athena Detector Proposal — A Totally Hermetic Electron Nucleus Apparatus Proposed For Ip6 At The Electron-Ion Collider, The Athena Collaboration Jan 2022

Athena Detector Proposal — A Totally Hermetic Electron Nucleus Apparatus Proposed For Ip6 At The Electron-Ion Collider, The Athena Collaboration

Physics and Astronomy Faculty Publications

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges.

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Trapped Surfaces, Topology Of Black Holes, And The Positive Mass Theorem, Lan-Hsuan Huang, Dan A. Lee Jan 2022

Trapped Surfaces, Topology Of Black Holes, And The Positive Mass Theorem, Lan-Hsuan Huang, Dan A. Lee

Publications and Research

No abstract provided.

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Collision-System And Beam-Energy Dependence Of Anisotropic Flow Fluctuations, Star Collaboration Jan 2022

Collision-System And Beam-Energy Dependence Of Anisotropic Flow Fluctuations, Star Collaboration

Physics and Astronomy Faculty Publications

Elliptic flow measurements from two-, four-, and six-particle correlations are used to investigate flow fluctuations in collisions of U+U at √𝑠NN=193  GeV, Cu+Au at √𝑠NN=200  GeV and Au+Au spanning the range √𝑠NN=11.5–200  GeV. The measurements show a strong dependence of the flow fluctuations on collision centrality, a modest dependence on system size, and very little if any, dependence on particle species and beam energy. The results, when compared to similar LHC measurements, viscous hydrodynamic calculations, and trento model eccentricities, indicate that initial-state-driven fluctuations predominate the flow fluctuations generated in the collisions studied.

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Differential Measurements Of Jet Substructure And Partonic Energy Loss In Au + Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration Jan 2022

Differential Measurements Of Jet Substructure And Partonic Energy Loss In Au + Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

The STAR collaboration presents jet substructure measurements related to both the momentum fraction and the opening angle within jets in 𝑝+𝑝 and Au+Au collisions at √𝑠𝑁⁢𝑁 =200GeV. The substructure observables include SoftDrop groomed momentum fraction (𝑧𝑔), groomed jet radius (𝑅𝑔), and subjet momentum fraction (𝑧SJ) and opening angle (𝜃SJ). The latter observable is introduced for the first time. Fully corrected subjet measurements are presented for 𝑝+𝑝 collisions and are compared to leading-order Monte Carlo models. The subjet 𝜃SJ distributions reflect the jets leading opening angle and are utilized as a proxy for the resolution scale of the medium in Au+Au …

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Disappearance Of Partonic Collectivity In √Snn = 3 Gev Au+Au Collisions At Rhic, Star Collaboration Jan 2022

Disappearance Of Partonic Collectivity In √Snn = 3 Gev Au+Au Collisions At Rhic, Star Collaboration

Physics and Astronomy Faculty Publications

We report on the measurements of directed flow v1 and elliptic flow v2 for hadrons (π±, K ±, K 0 S , p, φ, Λ and Ξ−) from Au+Au collisions at √sNN = 3 GeV and v2 for (π±, K ±, p and p) at 27 and 54.4 GeV with the STAR experiment. While at the two higher energy midcentral collisions the number-of-constituent-quark (NCQ) scaling holds, at 3 GeV the v2 at midrapidity is negative for all hadrons and the NCQ scaling is absent. In addition, the v1 slopes at midrapidity for almost all observed hadrons are found to be …

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Long-Term Rotational Evolution Of The Stis Ccd Flatfields, Kimberly Ward-Huong, S. Lockwood, J. Debes, R. J. De Rosa Jan 2022

Long-Term Rotational Evolution Of The Stis Ccd Flatfields, Kimberly Ward-Huong, S. Lockwood, J. Debes, R. J. De Rosa

Astronomy: Faculty Publications

We confirm a long-term rotational drift of 0.0031 degrees/year of the STIS CCD based upon analysis of 50CCD flatfields spanning over 20 years of calibration data. Using the dust motes present in the flatfields, we extract the positions of the motes in each image, allowing us to develop a catalog of stable, high ‘signal-to-noise’ mote features and track their relative positions over time. We find that the motes appear to be moving at the aforementioned rate relative to an approximate center of rotation located at X=468.02, Y=411.18 in detector pixel coordinates. Given the relatively large errors in centroiding the unusually-shaped …

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Magnetic Microscopy And Search For Exotic Interaction Detection With Color Centers In Diamond, Nathaniel Ristoff Jan 2022

Magnetic Microscopy And Search For Exotic Interaction Detection With Color Centers In Diamond, Nathaniel Ristoff

Physics & Astronomy ETDs

Nitrogen vacancy (NV) centers have been used extensively for the measurement of magnetic fields in applications of geology, biology, medicine, and fundamental physics. In regard to fundamental physics, NV centers offer a unique opportunity to test potential velocity dependant spin-spin interactions as well as velocity-spin interactions at the micron scale. In regards to magnetic materials, NV centers offer a platform to investigate magnetic properties of nanoparticles in an individual, but highly parallelized measurement. In this work, an experiment is proposed to measure a potential fundamental interaction between spins, mediated by an integer spin boson. These velocity dependent interactions will couple …

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Superluminal Propagation On A Moving Braneworld, Brian Greene, Daniel Kabat, Janna Levin, Arjun S. Menon Jan 2022

Superluminal Propagation On A Moving Braneworld, Brian Greene, Daniel Kabat, Janna Levin, Arjun S. Menon

Publications and Research

We consider a braneworld scenario in the simplest setting, M4 × S1, with a four-dimensional (4D) Minkowski metric induced on the brane, and establish the possibility of superluminal propagation. If the brane is at rest, the 4D Lorentz symmetry of the brane is exact, but if the brane is in motion, it is broken globally by the compactification. By measuring bulk fields, an observer on the brane sees a slice through a higher-dimensional field profile, which carries an imprint of the extra dimensions even when the brane is at rest. If the brane is in motion, we …

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The Octagon At Large M, Riccardo Argurio, Matteo Bertolini, Sebastían Franco, Eduardo García-Valdecasas, Shani Meynet, Antoine Pasternak, Valdo Tatitscheff Jan 2022

The Octagon At Large M, Riccardo Argurio, Matteo Bertolini, Sebastían Franco, Eduardo García-Valdecasas, Shani Meynet, Antoine Pasternak, Valdo Tatitscheff

Publications and Research

Recently, the first instance of a model of D-branes at Calabi-Yau singularities where supersymmetry is broken dynamically into stable vacua has been proposed. This construction was based on a system of N regular and M = 1 fractional branes placed at the tip of the so-called (orientifolded) Octagon singularity. In this paper we show that this model admits a large M generalization, having the same low energy effective dynamics. This opens up the possibility that the effect on geometry is smooth, and amenable to describing the gauge theory all along the RG flow, including the deep IR, in terms of …

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Characterizing The Particle Size Distribution In Saturn's Rings Using Cassini Uvis Stellar Occultation Data, Stephanie Eckert Jan 2022

Characterizing The Particle Size Distribution In Saturn's Rings Using Cassini Uvis Stellar Occultation Data, Stephanie Eckert

Electronic Theses and Dissertations, 2020-2023

NASA's Cassini mission to Saturn revolutionized modern understanding of the planet's vast and intricate ring system. We use stellar occultation data from Cassini's UVIS High Speed Photometer (HSP) to characterize the particle size distribution in the rings with two methods. First, we discern the sizes of the smallest particles at ring edges by forward-modeling observed diffraction signatures which appear as spikes in the signal, the shape and amplitude of which depends on the size and abundance of the smallest particles. We then probe the upper end of the size distribution using occultation statistics. Although the distribution of photon counts in …

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Atmospheric Retrieval: Bayesian Methods, Machine Learning, And Application To Exoplanets, Michael Himes Jan 2022

Atmospheric Retrieval: Bayesian Methods, Machine Learning, And Application To Exoplanets, Michael Himes

Electronic Theses and Dissertations, 2020-2023

Atmospheric retrieval is the inverse modeling method where atmospheric properties are constrained based on measured spectra. Due to the low signal-to-noise ratios of exoplanet observations, exoplanetary retrieval codes pair a radiative transfer (RT) simulator with a Bayesian statistical framework in order to characterize the distribution of atmospheric parameters that could explain the observations (the posterior distribution). This requires on the order of 106 RT model evaluations, which requires hours to days of compute time depending on model complexity. In this work, I investigate atmospheric retrieval methods and apply them to observations of hot Jupiters. Chapter 2 presents a set of …

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Surface Morphologies In A Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile, Nancy W. Hinman, Michael H. Hofmann, Kimberly Warren-Rhodes, Michael S. Phillips, Nora Noffke, Nathalie A. Cabrol, Guillermo Chong Diaz, Cecilia Demergasso, Cinthya Tebes-Cayo, Oscar Cabestro, Janice L. Bishop, Virginia C. Gulick, David Summers, Pablo Sobron, Michael Mcinenly, Jeffrey Moersch, Constanza Rodriguez, Philippe Sarazzin, Kevin L. Rhodes, Camila Javiera Riffo Contreras, David Wettergreen, Victor Parro Jan 2022

Surface Morphologies In A Mars-Analog Ca-Sulfate Salar, High Andes, Northern Chile, Nancy W. Hinman, Michael H. Hofmann, Kimberly Warren-Rhodes, Michael S. Phillips, Nora Noffke, Nathalie A. Cabrol, Guillermo Chong Diaz, Cecilia Demergasso, Cinthya Tebes-Cayo, Oscar Cabestro, Janice L. Bishop, Virginia C. Gulick, David Summers, Pablo Sobron, Michael Mcinenly, Jeffrey Moersch, Constanza Rodriguez, Philippe Sarazzin, Kevin L. Rhodes, Camila Javiera Riffo Contreras, David Wettergreen, Victor Parro

OES Faculty Publications

Salar de Pajonales, a Ca-sulfate salt flat in the Chilean High Andes, showcases the type of polyextreme environment recognized as one of the best terrestrial analogs for early Mars because of its aridity, high solar irradiance, salinity, and oxidation. The surface of the salar represents a natural climate-transition experiment where contemporary lagoons transition into infrequently inundated areas, salt crusts, and lastly dry exposed paleoterraces. These surface features represent different evolutionary stages in the transition from previously wetter climatic conditions to much drier conditions today. These same stages closely mirror the climate transition on Mars from a wetter early Noachian to …

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Visible Opacity Of M Dwarfs And Hot Jupiters: The Tio B³Π-X³Δ Band System, W. Doug Cameron, Peter Bernath Jan 2022

Visible Opacity Of M Dwarfs And Hot Jupiters: The Tio B³Π-X³Δ Band System, W. Doug Cameron, Peter Bernath

Chemistry & Biochemistry Faculty Publications

The TiO B3Π−X3Δ electronic transition (𝛾' system) is an important opacity source in the atmospheres of M dwarfs and hot Jupiter exoplanets. The 0–0, 1–0, and 2–1 bands of the B3Π−X3Δ band system have been analyzed using a TiO emission spectrum recorded at the McMath-Pierce Solar Telescope, operated by the National Solar Observatory at Kitt Peak, Arizona. Improved spectroscopic and equilibrium constants were determined. Line strengths were calculated from an ab initio transition-dipole moment function scaled using an experimental lifetime. A new line list for v' = 0–2 and v′′ = 0–4 …

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Testing Effects Of Lorentz Invariance Violation In The Propagation Of Astroparticles With The Pierre Auger Observatory, P. Abreu, M. Aglietta, J. M. Albury, I. Allekotte, K. Almeida Cheminant Jan 2022

Testing Effects Of Lorentz Invariance Violation In The Propagation Of Astroparticles With The Pierre Auger Observatory, P. Abreu, M. Aglietta, J. M. Albury, I. Allekotte, K. Almeida Cheminant

Faculty Publications

Lorentz invariance violation (LIV) is often described by dispersion relations of the form E-i(2) = m(i)(2) + p(i)(2) + delta E-i,n(2+ n) with delta different based on particle type i, with energy E, momentum p and rest mass m. Kinematics and energy thresholds of interactions are modified once the LIV terms become comparable to the squared masses of the particles involved. Thus, the strongest constraints on the LIV coefficients delta(i,n) tend to come from the highest energies. At sufficiently high energies, photons produced by cosmic ray interactions as they propagate through the Universe could be subluminal and unattenuated over cosmological …

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Bending Waves Excited By Irregular Gas Inflow Along Warps, Tigran Khachaturyants, Leandro Beraldo E Silva, Victor P. Debattista, Kathryne J. Daniel Jan 2022

Bending Waves Excited By Irregular Gas Inflow Along Warps, Tigran Khachaturyants, Leandro Beraldo E Silva, Victor P. Debattista, Kathryne J. Daniel

Physics Faculty Research and Scholarship

Gaia has revealed clear evidence of bending waves in the vertical kinematics of stars in the solar neighbourhood. We study bending waves in two simulations, one warped, with the warp due to misaligned gas inflow, and the other unwarped. We find slow, retrograde bending waves in both models, with the ones in the warped model having larger amplitudes. We also find fast, prograde bending waves. Prograde bending waves in the unwarped model are very weak, in agreement with the expectation that these waves should decay on short, approximately crossing, time-scales, due to strong winding. However, prograde bending waves are much …

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Development Of A Fluxgate Magnetometer Model, Eleonora Olsmats Jan 2022

Development Of A Fluxgate Magnetometer Model, Eleonora Olsmats

Honors Theses and Capstones

As a part of the UNH SWFO-L1 mission to monitor space weather and the sun’s behavior, the fluxgate magnetometer is an important component to measure external magnetic fields. The basic principle of a fluxgate magnetometer is to detect changes in the ambient magnetic field by inducing a magnetic field in a ferromagnetic material via a drive winding. Each magnetometer is unique due to the ferromagnetic properties of the core material which can be seen in the hysteresis loop which is a relationship between the magnetic field strength (H) and the induced magnetic field (B). Measuring the hysteresis of a fluxgate …

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Direct Imaging & Spectroscopy Of Exoplanetary Systems With The Jwst Early Release Science Program, Sasha Hinkley, Aarynn L. Carter, Shrishmoy Ray, Beth Biller, Andrew Skemer, Elodie Choquet, Maxwell A. Millar-Blanchaer, Stephanie Sallum, Brittany Miles, Niall Whiteford, Polychronis Patapis, Marshall Perrin, Laurent Pueyo, Karl Stapelfeldt, Jason Wang, Kimberly Ward-Duong, Julien H. Girard, Dean Hines, Jens Kammerer, Jarron Leisenring, Yifan Zhou, Michael Meyer, Michael C. Liu, Mickael Bonnefoy, Simon Petrus, Mariangela Bonavita, Gael Chauvin, Christine Chen, Thayne Currie, Kielan K.W. Hoch, Cecilia Lazzoni, Elisabeth C. Matthews Jan 2022

Direct Imaging & Spectroscopy Of Exoplanetary Systems With The Jwst Early Release Science Program, Sasha Hinkley, Aarynn L. Carter, Shrishmoy Ray, Beth Biller, Andrew Skemer, Elodie Choquet, Maxwell A. Millar-Blanchaer, Stephanie Sallum, Brittany Miles, Niall Whiteford, Polychronis Patapis, Marshall Perrin, Laurent Pueyo, Karl Stapelfeldt, Jason Wang, Kimberly Ward-Duong, Julien H. Girard, Dean Hines, Jens Kammerer, Jarron Leisenring, Yifan Zhou, Michael Meyer, Michael C. Liu, Mickael Bonnefoy, Simon Petrus, Mariangela Bonavita, Gael Chauvin, Christine Chen, Thayne Currie, Kielan K.W. Hoch, Cecilia Lazzoni, Elisabeth C. Matthews

Astronomy: Faculty Publications

The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for the broader exoplanet community. As large space missions will be necessary for detecting and characterizing exo-Earth twins, developing the techniques and technology for direct imaging of exoplanets is a driving focus for the community. For the first time, JWST will directly observe extrasolar planets at mid-infrared wavelengths beyond 5 μm, deliver detailed spectroscopy revealing much more precise chemical abundances and atmospheric conditions, and provide sensitivity to analogs of our solar system ice-giant planets at wide orbital separations, an entirely new class of exoplanet. However, …

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Performance Of Near-Infrared High-Contrast Imaging Methods With Jwst From Commissioning, Jens Kammerer, Julien Girard, Aarynn L. Carter, Marshall D. Perrin, Rachel Cooper, Deepashri Thatte, Thomas Vandal, Jarron Leisenring, Jason Wang, William O. Balmer, Anand Sivaramakrishnan, Laurent Pueyo, Kimberly Ward-Duong, Ben Sunnquist, Jéa Adams Redai Jan 2022

Performance Of Near-Infrared High-Contrast Imaging Methods With Jwst From Commissioning, Jens Kammerer, Julien Girard, Aarynn L. Carter, Marshall D. Perrin, Rachel Cooper, Deepashri Thatte, Thomas Vandal, Jarron Leisenring, Jason Wang, William O. Balmer, Anand Sivaramakrishnan, Laurent Pueyo, Kimberly Ward-Duong, Ben Sunnquist, Jéa Adams Redai

Astronomy: Faculty Publications

The James Webb Space Telescope (JWST) will revolutionize the field of high-contrast imaging and enable both the direct detection of Saturn-mass planets and the characterization of substellar companions in the mid-infrared. While JWST will feature unprecedented sensitivity, angular resolution will be the key factor when competing with ground-based telescopes. Here, we aim to characterize the performance of several extreme angular resolution imaging techniques available with JWST in the 3-5 µm regime based on data taken during the instrument commissioning. Firstly, we introduce custom tools to simulate, reduce, and analyze JWST NIRCam and MIRI coronagraphy data and use these tools to …

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Centrality And Transverse-Momentum Dependence Of Higher-Order Flow Harmonics Of Identified Hadrons In Au+Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration Jan 2022

Centrality And Transverse-Momentum Dependence Of Higher-Order Flow Harmonics Of Identified Hadrons In Au+Au Collisions At √𝑠𝑁⁢𝑁=200 Gev, Star Collaboration

Physics and Astronomy Faculty Publications

We present high-precision measurements of elliptic, triangular, and quadrangular flow 𝑣2, 𝑣3, and 𝑣4, respectively, at midrapidity for identified hadrons 𝜋, 𝑝, 𝐾, 𝜑, 𝐾𝑠, Λ as a function of centrality and transverse momentum in Au+Au collisions at the center-of-mass energy √𝑠𝑁⁢𝑁=200 GeV. We observe similar 𝑣𝑛 trends between light and strange mesons which indicates that the heavier strange quarks flow as strongly as the lighter up and down quarks. The number-of-constituent-quark scaling for 𝑣2, 𝑣3, and 𝑣4 is found to hold within statistical uncertainty for 0–10%, 10–40%, and 40–80% collision centrality intervals. The results are compared to several viscous …

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Azimuthal Transverse Single-Spin Asymmetries Of Inclusive Jets And Identified Hadrons Within Jets From Polarized 𝑝⁢𝑝 Collisions At √𝑠 =200  Gev, Star Collaboration Jan 2022

Azimuthal Transverse Single-Spin Asymmetries Of Inclusive Jets And Identified Hadrons Within Jets From Polarized 𝑝⁢𝑝 Collisions At √𝑠 =200  Gev, Star Collaboration

Physics and Astronomy Faculty Publications

The STAR Collaboration reports measurements of the transverse single-spin asymmetries, 𝐴𝑁, for inclusive jets and identified “hadrons within jets” production at midrapidity from transversely polarized 𝑝⁢𝑝 collisions at √𝑠 =200  GeV, based on data recorded in 2012 and 2015. The inclusive jet asymmetry measurements include 𝐴𝑁 for inclusive jets and 𝐴𝑁 for jets containing a charged pion carrying a momentum fraction 𝑧 >0.3 of the jet momentum. The identified hadron within jet asymmetry measurements include the Collins effect for charged pions, kaons, and protons, and the Collins-like effect for charged pions. The measured asymmetries are determined for several distinct kinematic …

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Evidence For Nonlinear Gluon Effects In Qcd And Their Mass Number Dependence At Star, Star Collaboration Jan 2022

Evidence For Nonlinear Gluon Effects In Qcd And Their Mass Number Dependence At Star, Star Collaboration

Physics and Astronomy Faculty Publications

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-𝜋0s produced at forward pseudorapidities (2.6 < 𝜂 < 4.0) in 𝑝 +𝑝, 𝑝+Al, and 𝑝+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back 𝜋0 pairs in 𝑝+Al and 𝑝+Au collisions compared to the 𝑝 +𝑝 data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in 𝑝+Au relative to 𝑝+Al collisions exhibits a dependence of the saturation scale 𝑄2/𝑠 on the mass number 𝐴. A linear scaling of the suppression with 𝐴1/3 is observed with a slope of −0.09 ±0.01.

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Osiris-Rex Surface Imaging To Constrain Properties Of The Asteroid (101955) Bennu, Alicia Allen Jan 2022

Osiris-Rex Surface Imaging To Constrain Properties Of The Asteroid (101955) Bennu, Alicia Allen

Honors Undergraduate Theses

This study used images taken from the OSIRIS-REx spacecraft sample-return mission and projected onto a three-dimensional shape model to determine surface properties of the asteroid (101955) Bennu. Two major projects were completed. For the first project, images of the pre-sampled Nightingale site and post-sampled Nightingale were compared to determine how the TAGSAM sampling maneuver effected the surface of the asteroid directly at the sampling site and in the surrounding area. This analysis demonstrated how spacecraft can potentially affect a small body during this and future sample-return missions. For the second project, several craters on Bennu’s surface were selected and all …

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Characterizing The Effects Of Porosity And Particle Size On Tir Emissivity Spectral Features Of Olivine, Ryan Galinkin Jan 2022

Characterizing The Effects Of Porosity And Particle Size On Tir Emissivity Spectral Features Of Olivine, Ryan Galinkin

Electronic Theses and Dissertations, 2020-2023

We generated a series of 15 particulate San Carlos olivine samples with varying porosity and particle size. We created five different particle size distributions and each particle size distribution was prepared with three different packing techniques. These samples were then imaged under a microscope and a binarization thresholding technique was used to determine each sample's surface porosity by the ratio of dark, void pixels to the total number of pixels in each image. Our results show that we could estimate surface porosity from the analysis of a microscopic image, a non-destructive technique. These samples were then placed in the Planetary …

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