The Gentle Growth Of Galaxies At High Redshifts In Overdense Environments,
2014
University of Bonn, Germany
The Gentle Growth Of Galaxies At High Redshifts In Overdense Environments, Emilio Romano-Díaz, Isaac Shlosman, Jun-Hwan Choi, Raphael Sadoun
Physics and Astronomy Faculty Publications
We have explored prevailing modes of galaxy growth for redshifts z ~ 6-14, comparing substantially overdense and normal regions of the universe, using high-resolution zoom-in cosmological simulations. Such rare overdense regions have been projected to host high-z quasars. We demonstrate that galaxies in such environments grow predominantly by a smooth accretion from cosmological filaments which dominates the mass input from major, intermediate, and minor mergers. We find that by z ~ 6, the accumulated galaxy mass fraction from mergers falls short by a factor of 10 of the cumulative accretion mass for galaxies in the overdense regions, and by …
Different Response Of Transport And Magnetic Properties Of Bairo3 To Chemical And Physical Pressure,
2014
CSIC-Universidad de Zaragoza, Spain
Different Response Of Transport And Magnetic Properties Of Bairo3 To Chemical And Physical Pressure, M. A. Laguna-Marco, G. Fabbris, N. M. Souza-Neto, S. Chikara, J. S. Schilling, Gang Cao, D. Haskel
Physics and Astronomy Faculty Publications
A combination of x-ray absorption, x-ray-diffraction, and transport measurements at high pressure is used to investigate the interplay between the electronic properties of Ir 5d states and lattice degrees of freedom in the weakly ferromagnetic insulator BaIrO3. Although the Ir 5d local magnetic moment is highly stable against lattice compression, remaining nearly unperturbed to at least 30 GPa, the weak ferromagnetism (net ordered moment) is quickly quenched by 4.5 GPa (3% volume reduction). Under chemical pressure, where Sr is substituted for the larger Ba in BaIrO3, the local magnetic moment on Ir remains stable, …
Casimir Energy Of Smooth Compact Surfaces,
2014
University of Kentucky
Casimir Energy Of Smooth Compact Surfaces, Joseph P. Straley, Eugene B. Kolomeisky
Physics and Astronomy Faculty Publications
We discuss the formalism of Balian and Duplantier [Balian and Duplantier, Ann. Phys. (NY) 104, 300 (1977); Balian and Duplantier, Ann. Phys. (NY) 112, 165 (1978)] for the calculation of the Casimir energy for an arbitrary smooth compact surface and use it to give some examples: a finite cylinder with hemispherical caps, a torus, an ellipsoid of revolution, a cube with rounded corners and edges, and a drum made of disks and part of a torus. We propose a model function that approximately captures the shape dependence of the Casimir energy.
Orbital-Dependent Polaron Formation In The Relativistic Mott Insulator Sr2Iro4,
2014
Seoul National University, Korea
Orbital-Dependent Polaron Formation In The Relativistic Mott Insulator Sr2Iro4, C. H. Sohn, Min-Cheol Lee, H. J. Park, Kyung Joo Noh, H. K. Yoo, S. J. Moon, K. W. Kim, T. F. Qi, Gang Cao, Deok-Yong Cho, T. W. Noh
Physics and Astronomy Faculty Publications
We use optical spectroscopy to investigate the electron-phonon interaction in Sr2IrO4, a well-known 5d transition metal oxide with spin-orbit entangled states. The temperature evolution in the optical spectra is well described by the Fröhlich polaron model, indicating a large electron-phonon interaction. We further find that electrons in different orbitals selectively couple with different phonon modes. While Jeff = 3/2 holes do not seem to couple with any phonons, Jeff = 1/2 and 3z2−r2 electrons mainly couple with in-plane and out-of-plane Ir-O bending modes, respectively. The symmetries of the …
Detection And Estimation Of Unmodeled Narrowband Nonstationary Signals: Application Of Particle Swarm Optimization In Gravitational Wave Data Analysis,
2014
The University of Texas Rio Grande Valley
Detection And Estimation Of Unmodeled Narrowband Nonstationary Signals: Application Of Particle Swarm Optimization In Gravitational Wave Data Analysis, Soumya Mohanty
Physics & Astronomy Faculty Publications
The extraction of weak signals from instrumental noise is a critical task in ongoing searches for gravitational waves. A detection and estimation method, made feasible by Particle Swarm Optimization, is presented for a particularly challenging class of signals expected from astrophysical sources.
X-Rays From Magnetically Confined Wind Shocks: Effect Of Cooling-Regulated Shock Retreat,
2014
Swarthmore College
X-Rays From Magnetically Confined Wind Shocks: Effect Of Cooling-Regulated Shock Retreat, A. Ud-Doula, S. Owocki, R. Townsend, V. Petit, David H. Cohen
Physics & Astronomy Faculty Works
We use 2D magnetohydrodynamic (MHD) simulations to examine the effects of radiative cooling and inverse Compton (IC) cooling on X-ray emission from magnetically confined wind shocks (MCWS) in magnetic massive stars with radiatively driven stellar winds. For the standard dependence of mass-loss rate on luminosity Ṁ∼ L1.7, the scaling of IC cooling with L and radiative cooling with Ṁ means that IC cooling become formally more important for lower luminosity stars. However, because the sense of the trends is similar, we find the overall effect of including IC cooling is quite modest. More significantly, for stars with high enough mass-loss …
Measurement Of The Target-Normal Single-Spin Asymmetry In Deep-Inelastic Scattering From The Reaction 3He↑(E,E′)X,
2014
University of Kentucky
Measurement Of The Target-Normal Single-Spin Asymmetry In Deep-Inelastic Scattering From The Reaction 3He↑(E,E′)X, K. Allada, C. Dutta, A. Kolarkar, Wolfgang Korsch, J. Katich, X. Qian, Y. X. Zhao, K. Aniol, J. R. M. Annand, T. Averett, F. Benmokhtar, W. Bertozzi, P. C. Bradshaw, P. Bosted
Physics and Astronomy Faculty Publications
We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3He↑(e,e′)X on a polarized 3He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7<W<2.9 GeV, 1.0<Q2<4.0 GeV2 and 0.16<x<6.5. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-3He cross-section ratios. The measured neutron asymmetries are negative with an average value of (−1.09±0.38)×10−2 for invariant mass W>2 …
A Numerical Simulation Of Solar Energetic Particle Dropouts During Impulsive Events,
2014
Chinese Academy of Sciences
A Numerical Simulation Of Solar Energetic Particle Dropouts During Impulsive Events, Yi Wáng, Gang Qin, Ming Zhang, Silvia Dalla
Aerospace, Physics, and Space Science Faculty Publications
This paper investigates the conditions for producing rapid variations of solar energetic particle (SEP) intensity commonly known as "dropouts." In particular, we use numerical model simulations based on solving the focused transport equation in the three-dimensional Parker interplanetary magnetic field to put constraints on the properties of particle transport coefficients in both directions perpendicular and parallel to the magnetic field. Our calculations of the temporal intensity profile of 0.5 and 5 MeV protons at the Earth show that the perpendicular diffusion must be small while the parallel mean free path is long in order to reproduce the phenomenon of SEP …
Local Density Of States Study Of A Spin-Orbit-Coupling Induced Mott Insulator Sr2Iro4,
2014
University of Colorado - Boulder
Local Density Of States Study Of A Spin-Orbit-Coupling Induced Mott Insulator Sr2Iro4, Jixia Dai, Eduardo Calleja, Gang Cao, Kyle Mcelroy
Physics and Astronomy Faculty Publications
We present scanning tunneling microscopy and spectroscopy experiments on the novel Jeff=1/2 Mott insulator Sr2IrO4. Local density of states (LDOS) measurements show an intrinsic insulating gap of 620 meV that is asymmetric about the Fermi level and is larger than previously reported values. The size of this gap suggests that Sr2IrO4 is likely a Mott rather than Slater insulator. In addition, we found a small number of native defects which create in-gap spectral weight. Atomically resolved LDOS measurements on and off the defects show that this energy gap is quite fragile. …
Dielectron Mass Spectra From Au+Au Collisions At √SNn<=200 Gev,
2014
University of Kentucky
Dielectron Mass Spectra From Au+Au Collisions At √SNn<=200 Gev, J. Kevin Adkins, Renee Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer
Physics and Astronomy Faculty Publications
We report the STAR measurements of dielectron (e+e−) production at midrapidity (|yee|SNN=200 GeV. The measurements are evaluated in different invariant mass regions with a focus on 0.30–0.76 (ρ-like), 0.76–0.80 (ω-like), and 0.98–1.05 (ϕ-like) GeV/c2. The spectrum in the ω-like and ϕ-like regions can be well described by the hadronic cocktail simulation. In the ρ-like region, however, the vacuum ρ spectral function cannot describe the shape of the dielectron excess. In this range, an enhancement of 1.77±0.11(stat)±0.24(syst)±0.33(cocktail) is determined …
Search For Gravitational Waves Associated With Γ-Ray Bursts Detected By The Interplanetary Network,
2014
Andrews University
Search For Gravitational Waves Associated With Γ-Ray Bursts Detected By The Interplanetary Network, Tiffany Summerscales, Ligo Scientific Collaboration, Virgo Collaboration, And Ipn Collaboration
Faculty Publications
We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005–2010 during LIGO’s fifth and sixth science runs and Virgo’s first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search …
A Uv To Mid-Ir Study Of Agn Selection,
2014
The Ohio State University
A Uv To Mid-Ir Study Of Agn Selection, Sun Mi Chung, Christopher S. Kochanek, Roberto Assef, Michael J. I. Brown, Daniel Stern, Buell T. Jannuzi, Anthony H. Gonzalez, Ryan C. Hickox, John Moustakas
Dartmouth Scholarship
We classify the spectral energy distributions (SEDs) of 431,038 sources in the 9 deg2 Boötes field of the NOAO Deep Wide-Field Survey (NDWFS). There are up to 17 bands of data available per source, including ultraviolet (GALEX), optical (NDWFS), near-IR (NEWFIRM), and mid-infrared (IRAC and MIPS) data, as well as spectroscopic redshifts for ~20,000 objects, primarily from the AGN and Galaxy Evolution Survey. We fit galaxy, active galactic nucleus (AGN), stellar, and brown dwarf templates to the observed SEDs, which yield spectral classes for the Galactic sources and photometric redshifts and galaxy/AGN luminosities for the extragalactic sources. …
Towards Stronger Coulomb Coupling In An Ultracold Neutral Plasma,
2014
Brigham Young University - Provo
Towards Stronger Coulomb Coupling In An Ultracold Neutral Plasma, Mary Elizabeth Lyon
Theses and Dissertations
Ultracold neutral plasmas are created by photoionizing laser-cooled atoms in a magneto-optical trap (MOT). Due to their large electrical potential energies and comparatively small kinetic energies, ultracold plasmas fall into a regime of plasma systems which are called “strongly coupled.” A priority in the field of ultracold plasmas is to generate plasmas with higher values of the strong coupling parameter Γ, which is given as the ratio of the nearest-neighbor Coulomb potential energy to the average kinetic energy. The equilibrium strong coupling in ultracold plasmas is limited by the ultrafast relaxation of the ions due to spatial disorder in the …
Misaligned Protoplanetary Disks In A Young Binary Star System,
2014
Swarthmore College
Misaligned Protoplanetary Disks In A Young Binary Star System, Eric L.N. Jensen, R. L. Akeson
Physics & Astronomy Faculty Works
Many extrasolar planets follow orbits that differ from the nearly coplanar and circular orbits found in our Solar System; their orbits may be eccentric or inclined with respect to the host star's equator, and the population of giant planets orbiting close to their host stars suggests appreciable orbital migration. There is at present no consensus on what produces such orbits. Theoretical explanations often invoke interactions with a binary companion star in an orbit that is inclined relative to the planet's orbital plane. Such mechanisms require significant mutual inclinations between the planetary and binary star orbital planes. The protoplanetary disks in …
Morphology And Environment Of Galaxies With Disc Breaks In The S4g And Nirs0s,
2014
Florida Institute of Technology
Morphology And Environment Of Galaxies With Disc Breaks In The S4g And Nirs0s, J. Laine, E. Laurikainen, H. Salo, S. Comeron, R. J. Buta, D. Zaritsky, E. Athanassoula, A. Bosma, J.-C. Munoz-Mateos, D. A. Gadotti, J. L. Hinz, S. Erroz-Ferrer, A. Gil De Paz, T. Kim, K. Menendez-Delmestre, T. Mizusawa, M. W. Regan, M. Seibert, K. Sheth
Aerospace, Physics, and Space Science Faculty Publications
We study the surface brightness profiles of disc galaxies in the 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies (S4G) and Ks-band images from the Near-Infrared S0-Sa galaxy Survey (NIRS0S). We particularly connect properties of single exponential (type I), downbending double exponential (type II), and upbending double exponential (type III) disc profile types, to structural components of galaxies by using detailed morphological classifications, and size measurements of rings and lenses. We also study how the local environment of the galaxies affects the profile types by calculating parameters describing the environmental density and the tidal …
Investigation Of A New Method Of Estimating Acoustic Intensity And Its Application To Rocket Noise,
2014
Brigham Young University - Provo
Investigation Of A New Method Of Estimating Acoustic Intensity And Its Application To Rocket Noise, Benjamin Young Christensen
Theses and Dissertations
An alternative pressure-sensor based method for estimating the acoustic intensity, the phase and amplitude gradient estimation (PAGE) method, is presented. This method is similar to the finite-difference p-p (FD) method, in which the intensity is estimated from pressure measurements made using an array of closely spaced microphones. The PAGE method uses the same hardware as the FD method, but does not suffer from the frequency-dependent bias inherent to the FD method. Detailed derivations of the new method and the traditional FD method are presented. Both methods are then compared using two acoustic fields: a plane wave and a three monopole …
Report On The Workshop For Life Detection In Samples From Mars,
2014
European Space Agency
Report On The Workshop For Life Detection In Samples From Mars, Gerhard Kminek, Catherine Conley, Carlton C. Allen, Douglas H. Bartlett, David W. Beaty, Liane G. Benning, Rohit Bhatia, Penelope J. Boston, Caroline Duchaine, Jack D. Farmer, George J. Flynn, Daniel P. Glavin, Yuri Gorby, John E. Hallsworth, Rakesh Mogul, Duane Moser, P. Buford Price, Ruediger Pukall, David Fernandez-Remolar, Caroline L. Smith, Kenneth M. Stedman, Andrew Steele, Ramunas Stepanauskas, Henry Sun, Jorge L. Vago, Mary A. Voytek, Paul S. Weiss, Frances Westfall
Biology Faculty Publications and Presentations
The question of whether there is or was life on Mars has been one of the most pivotal since Schiaparellis’ telescopic observations of the red planet. With the advent of the space age, this question can be addressed directly by exploring the surface of Mars and by bringing samples to Earth for analysis. The latter, however, is not free of problems. Life can be found virtually everywhere on Earth. Hence the potential for contaminating the Mars samples and compromising their scientific integrity is not negligible. Conversely, if life is present in samples from Mars, this may represent a potential source …
Introduction To The Development Of A Radio Astronomy System At Brigham Young University,
2014
Brigham Young University - Provo
Introduction To The Development Of A Radio Astronomy System At Brigham Young University, Daniel Robert Blakley
Theses and Dissertations
The intent of this project was founded upon the need to train students in the techniques of radio astronomy with the purpose of establishing a radio telescope in order to teach the principles and practice of radio astronomy.This document describes the theory, research, to establish the 1st generation radio telescope system within the Department of Physics and Astronomy at Brigham Young University. Included are introductions to: (1) The nature of star forming regions in the spiral arm structure of the galaxy, H I (the hydrogen spin-flip transition) and OH MASERS, (2) The of terminology used with the system components and …
Semi-Inclusive Charged-Current Neutrino-Nucleus Reactions,
2014
Old Dominion University
Semi-Inclusive Charged-Current Neutrino-Nucleus Reactions, O. Moreno, T. W. Donnelly, J. W. Van Orden, W. P. Ford
Physics Faculty Publications
The general, universal formalism for semi-inclusive charged-current (anti) neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized, and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case …
Globular Cluster Simulations By Mocca Code,
2014
University of Texas at Brownsville
Globular Cluster Simulations By Mocca Code, Dongming Jin
Theses and Dissertations - UTB/UTPA
The MOCCA code is one of the most advanced codes that has the capacity to simulate a realistic sized star cluster with a full dynamical history including stellar evolution using Monte Carlo methods for the cluster evolution and the Fewbody code for scattering. The dynamical evolution of a cluster can result in the formation of many binary systems. Some of these binaries may be very close. Close double white dwarf binaries (double WDBs) may be promising gravitational wave sources. Our work uses MOCCA to simulate 90 globular clusters with different numbers of stars, binary fractions, metallicities and power-law indices of …
