Characteristics Of Two-Episode Emission Patterns In Fermi Long Gamma-Ray Bursts,
2018
Guangxi University
Characteristics Of Two-Episode Emission Patterns In Fermi Long Gamma-Ray Bursts, Lin Lan, Hou-Jun Lü, Shu-Qing Zhong, Hai-Ming Zhang, Jared Rice, Ji-Gui Cheng, Shen-Shi Du, Long Li, Jie Lin, Rui-Jing Lu, En-Wei Liang
Physics & Astronomy Faculty Research
Two-episode emission components separated by quiescent gaps in the prompt emission of gamma-ray bursts (GRBs) have been observed in the Swift era, but there is a lack of spectral information due to the narrow energy band of the Swift/Burst Alert Telescope. In this paper, a systematic analysis of the spectral and temporal properties of the prompt emission of 101 Fermi/Gamma-ray Burst Monitor detected long GRBs show the existence of two-episode emission components in the light curves, with quiescent times of up to hundreds of seconds. We focus on investigating the differences of those two emission episodes. We find that the …
Polarized Bow Shock Nebulae Reveal Features Of The Winds And Environments Of Massive Stars,
2018
University of Denver
Polarized Bow Shock Nebulae Reveal Features Of The Winds And Environments Of Massive Stars, Manisha Shrestha
Electronic Theses and Dissertations
Massive stars strongly affect their surroundings through their energetic stellar winds during their lifetime and through their energetic deaths as supernovae. When a stellar wind interacts with the local interstellar medium (ISM), if the relative velocity between wind and ISM is supersonic, then a stellar wind bow shock is formed. Bow shocks and related density enhancements produced by the winds of massive stars moving through the interstellar medium provide important information regarding the motions of the stars, the properties of their stellar winds, and the characteristics of the local medium. Since bow shock nebulae are aspherical structures, light scattering within …
Fluctuating Hydrodynamics Of Reactive Liquid Mixtures,
2018
University of California, Merced
Fluctuating Hydrodynamics Of Reactive Liquid Mixtures, Changho Kim, Andy. Nonaka, John Bell, Alejandro Garcia, Aleksandar Donev
Faculty Publications
Fluctuating hydrodynamics (FHD) provides a framework for modeling microscopic fluctuations in a manner consistent with statistical mechanics and nonequilibrium thermodynamics. This paper presents an FHD formulation for isothermal reactive incompressible liquid mixtures with stochastic chemistry. Fluctuating multispecies mass diffusion is formulated using a Maxwell–Stefan description without assuming a dilute solution, and momentum dynamics is described by a stochastic Navier–Stokes equation for the fluid velocity. We consider a thermodynamically consistent generalization for the law of mass action for non-dilute mixtures and use it in the chemical master equation (CME) to model reactions as a Poisson process. The FHD approach provides remarkable …
Direct Imaging Of The Hd 35841 Debris Disk: A Polarized Dust Ring From Gemini Planet Imager And An Outer Halo From Hst/Stis,
2018
University of California, Berkeley
Direct Imaging Of The Hd 35841 Debris Disk: A Polarized Dust Ring From Gemini Planet Imager And An Outer Halo From Hst/Stis, Thomas M. Esposito, Gaspard Duchne, Paul Kalas, Malena Rice, Ilodie Choquet, Bin Ren, Marshall D. Perrin, Christine H. Chen, Pauline Arriaga, Eugene Chiang, Eric L. Nielsen, James R. Graham, Jason J. Wang, Robert J.De Rosa, Katherine B. Follette, S. Mark Ammons, Megan Ansdell, Vanessa P. Bailey, Travis Barman, Juan Sebastián Bruzzone, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Michael P. Fitzgerald, Stephen J. Goodsell, Alexandra Z. Greenbaum, Pascale Hibon, Li Wei Hung, Patrick Ingraham, Quinn Konopacky, James E. Larkin, Kimberly Ward-Duong, Et Al
Astronomy: Faculty Publications
We present new high resolution imaging of a light-scattering dust ring and halo around the young star HD 35841. Using spectroscopic and polarimetric data from the Gemini Planet Imager in H-band (1.6 μm), we detect the highly inclined (i = 85°) ring of debris down to a projected separation of ∼12 au (∼0.″12) for the first time. Optical imaging from HST/STIS shows a smooth dust halo extending outward from the ring to >140 au (>1.″4). We measure the ring's scattering phase function and polarization fraction over scattering angles of 22°-125°, showing a preference for forward scattering and a polarization …
Strong Evidence For The Density-Wave Theory Of Spiral Structure From A Multi-Wavelength Study Of Disk Galaxies,
2018
University of Arkansas, Fayetteville
Strong Evidence For The Density-Wave Theory Of Spiral Structure From A Multi-Wavelength Study Of Disk Galaxies, Hamed Pour-Imani
Graduate Theses and Dissertations
The density-wave theory of spiral structure, though first proposed as long ago as the mid-1960s by C.C. Lin and F. Shu (Lin & Shu, 1964; Bertin & Lin, 1996; Shu, 2016), continues to be challenged by rival theories, such as the manifold theory. One test of these theories which has been proposed is that the pitch angle of spiral arms for galaxies should vary with the wavelength of the image in the density-wave theory, but not in the manifold theory. The reason is that stars are born in the density wave but move out of it as they age. In …
High Dynamic Range Optical Devices And Applications.,
2018
University of Louisville
High Dynamic Range Optical Devices And Applications., Elijah Robert Jensen
Electronic Theses and Dissertations
Much of what we know about fundamental physical law and the universe derives from observations and measurements using optical methods. The passive use of the electromagnetic spectrum can be the best way of studying physical phenomenon in general with minimal disturbance of the system in the process. While for many applications ambient visible light is sufficient, light outside of the visible range may convey more information. The signals of interest are also often a small fraction of the background, and their changes occur on time scales so quickly that they are visually imperceptible. This thesis reports techniques and technologies developed …
On Some Metaphysical Problems Of Many Worlds Interpretation Of Quantum Mechanics,
2018
University of New Mexico
On Some Metaphysical Problems Of Many Worlds Interpretation Of Quantum Mechanics, Florentin Smarandache, Victor Christianto, Yunita Umniyati
Branch Mathematics and Statistics Faculty and Staff Publications
Despite its enormous practical success, many physicists and philosophers alike agree that the quantum theory is full of contradictions and paradoxes which are difficult to solve consistently. Even after 90 years, the experts themselves still do not all agree what to make of it. The area of disagreement centers primarily around the problem of describing observations. Formally, the socalled quantum measurement problem can be defined as follows: the result of a measurement is a superposition of vectors, each representing the quantity being observed as having one of its possible values. The question that has to be answered is : how …
First Measurement Of Ξ− Polarization In Photoproduction,
2018
Old Dominion University
First Measurement Of Ξ− Polarization In Photoproduction, J. Bono, L. Guo, K. P. Adhikari, M. J. Amaryan, G. Charles, G. Gavalian, M. Khachatryan, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao
Physics Faculty Publications
Despite decades of studies of the photoproduction of hyperons, both their production mechanisms and their spectra of excited states are still largely unknown. While the parity-violating weak decay of hyperons offers a means of measuring their polarization, which could help discern their production mechanisms and identify their excitation spectra, no such study has been possible for doubly strange baryons in photoproduction, due to low production cross sections. However, by making use of the reaction γ p → K+K+Ξ−, we have measured, for the first time, the induced polarization, P, and the transferred polarization from circularly polarized …
Effect Of Chemistry On Electrodynamics In The Martian Dynamo Region,
2018
Embry-Riddle Aeronautical University
Effect Of Chemistry On Electrodynamics In The Martian Dynamo Region, Morgan M. Matheny
Doctoral Dissertations and Master's Theses
Electromagnetic interactions between Mars remnant crustal magnetic fields and solar and planetary ions lead to time and space variations of the ionosphere. In this work, we continue the investigations started by Riousset et al. [2013] and address the effect of chemistry on ion populations in the dynamo region, where ion dynamics are driven by collisions while electrons are still mostly magnetized. We adopt a mesoscale model to simulate dynamics of electrons and ions in the upper atmosphere (100–400 km). Our approach focuses on numerical studies using the Martian Multifluid Magnetohy drodynamic (MF-MHD) Model (M4). The dynamo is a region which …
Rossby Vortices In Thin Magnetized Accretion Discs,
2018
Cornell University
Rossby Vortices In Thin Magnetized Accretion Discs, L. Matilsky, Sergei Dyda, R. V. E. Lovelace, P. S. Lii
Physics & Astronomy Faculty Research
We study the Rossby wave instability (RWI) in a thin accretion disc threaded by an initially toroidal magnetic field using the magnetohydrodynamics (MHD) code PLUTO... See full text for full abstract.
Analysis Of Nucleus Properties Of The Enigmatic Comet 29p/Schwassmann-Wachmann 1,
2018
University of Central Florida
Analysis Of Nucleus Properties Of The Enigmatic Comet 29p/Schwassmann-Wachmann 1, Charles Schambeau
Electronic Theses and Dissertations
We present results from a continuing effort to understand activity drivers for the enigmatic Comet 29P/Schwassmann-Wachmann 1 (SW1). SW1 has been of interest since its discovery almost 100 years ago because of its nearly continuous, quiescent activity beyond the water-sublimation line and its highly variable, outburst activity while receiving a nearly constant insolation due to its low eccentricity orbit. These characteristics make SW1 a useful target for investigating both distant cometary activity drivers and also cometary outburst behavior. We approach answering these questions through a detailed analysis of SW1; first by measuring nucleus properties required for a more accurate nucleus …
Erratum: The Sluggs Survey: A Comparison Of Total-Mass Profiles Of Early-Type Galaxies From Observations And Cosmological Simulations, To ∼4 Effective Radii,
2018
Swinburne University of Technology
Erratum: The Sluggs Survey: A Comparison Of Total-Mass Profiles Of Early-Type Galaxies From Observations And Cosmological Simulations, To ∼4 Effective Radii, Sabine Bellstedt, Duncan Forbes, Aaron Romanowsky, Rhea-Silvia Remus, Adam Stevens, Jean Brodie, Adriano Poci, Richard Mcdermid, Adebusola Alabi, Leonie Chevalier, Caitlin Adams, Anna Ferré-Mateu, Asher Wasserman, Viraj Pandya
Faculty Publications
This is an erratum to the paper “The SLUGGS Survey: A comparison of total-mass profiles of early-type galaxies from observations and cosmological simulations, to ∼4 effective radii” that was published in 2018, MNRAS, 476, 4543, which we refer to as the original paper.
Cause Of Cambrian Explosion - Terrestrial Or Cosmic?,
2018
CY O'Connor ERADE Village Foundation
Cause Of Cambrian Explosion - Terrestrial Or Cosmic?, Edward J. Steele, Shirwan Al-Mufti, Kenneth A. Augustyn, Rohana Chandrajith, John P. Coghlan, S. G. Coulson, Et. Al.
Michigan Tech Publications, Part 1
We review the salient evidence consistent with or predicted by the Hoyle-Wickramasinghe (H-W) thesis of Cometary (Cosmic) Biology. Much of this physical and biological evidence is multifactorial. One particular focus are the recent studies which date the emergence of the complex retroviruses of vertebrate lines at or just before the Cambrian Explosion of ∼500 Ma. Such viruses are known to be plausibly associated with major evolutionary genomic processes. We believe this coincidence is not fortuitous but is consistent with a key prediction of H-W theory whereby major extinction-diversification evolutionary boundaries coincide with virus-bearing cometary-bolide bombardment events. A second focus is …
Force Multiplier Calculations For X-Ray Binaries And Active Galactic Nuclei,
2018
University of Nevada, Las Vegas
Force Multiplier Calculations For X-Ray Binaries And Active Galactic Nuclei, Randall Cody Dannen
UNLV Theses, Dissertations, Professional Papers, and Capstones
Motivated by the work done to explore the winds from hot stars (Lamers & Cassinelli 1999), we develop a method for self consistently calculating force multipliers for Type 1 and Type 2 active galactic nuclei (AGN), soft and hard start X-ray binaries (XRBs) spectral energy distributions (SEDs). We find that the ampflication to the radiation force can be as large as 100 even when the gas is highly ionized due to Fe and O ions. We discuss future efforts to incorporate these findings in magnetohydrodynamic simulations.
Collisional Quenching Of Highly Excited H2 Due To H2 Collisions,
2018
The University of Georgia
Collisional Quenching Of Highly Excited H2 Due To H2 Collisions, Yier Wan, B. H. Yang, P. C. Stancil, Balakrishnan Naduvalath, Nikhil J. Parekh, R. C. Forrey
Chemistry and Biochemistry Faculty Research
Rate coefficients for pure rotational quenching in H2(ν 1 = 0, j 1) + H2(ν 2 = 0, j 2) collisions from initial levels of j 1 = 2–31 (j 2 = 0 or 1) to all lower rotational levels are presented. We carried out extensive quantum mechanical close-coupling calculations based on a recently published H2–H2 potential energy surface (PES) developed by Patkowski et al. that has been demonstrated to be more reliable than previous work. Rotational transition cross sections with initial levels of j 1 = 2–14, 18, 19, 24, and 25 were computed for energies ranging from 10−6 …
Space-Time In The Syk Model,
2018
University of Kentucky
Space-Time In The Syk Model, Sumit R. Das, Aminik Ghosh, Antal Jevicki, Kenta Suzuki
Physics and Astronomy Faculty Publications
We consider the question of identifying the bulk space-time of the SYK model. Focusing on the signature of emergent space-time of the (Euclidean) model, we explain the need for non-local (Radon-type) transformations on external legs of n-point Green’s functions. This results in a dual theory with Euclidean AdS signature with additional legfactors. We speculate that these factors incorporate the coupling of additional bulk states similar to the discrete states of 2d string theory.
Gamma-Ray Burst/Supernova Associations: Energy Partition And The Case Of A Magnetar Central Engine,
2018
Guangxi University
Gamma-Ray Burst/Supernova Associations: Energy Partition And The Case Of A Magnetar Central Engine, Hon-Jun Lü, Lin Lan, Bing Zhang, En-Wei Liang, David Alexander Kann, Shen-Shi Du, Jun Shen
Physics & Astronomy Faculty Research
The favored progenitor model for Gamma-ray Bursts (GRBs) with Supernova (SN) association is the core collapse of massive stars. One possible outcome of such a collapse is a rapidly spinning, strongly magnetized neutron star ("magnetar"). We systematically analyze the multi-wavelength data of GRB/SN associations detected by several instruments before 2017 June. Twenty GRB/SN systems have been confirmed via direct spectroscopic evidence or a clear light curve bump, as well as some spectroscopic evidence resembling a GRB-SN. We derive/collect the basic physical parameters of the GRBs and the SNe, and look for correlations among these parameters. We find that the peak …
Systematic Mischaracterization Of Exoplanetary System Dynamical Histories From A Model Degeneracy Near Mean-Motion Resonance,
2018
University of Nevada, Las Vegas
Systematic Mischaracterization Of Exoplanetary System Dynamical Histories From A Model Degeneracy Near Mean-Motion Resonance, John H. Boisvert, Benjamin E. Nelson, Jason H. Steffen
Physics & Astronomy Faculty Research
There is a degeneracy in the radial velocity exoplanet signal between a single planet on an eccentric orbit and a two-planet system with a period ratio of 2:1. This degeneracy could lead to misunderstandings of the dynamical histories of planetary systems as well as measurements of planetary abundances if the correct architecture is not established. We constrain the rate of mischaracterization by analysing a sample of 60 non-transiting, radial velocity systems orbiting main-sequence stars from the NASA Exoplanet Archive (NASA Archive) using a new Bayesian model comparison pipeline. We find that 15 systems (25 per cent of our sample) show …
Globular Cluster Population Of The Hst Frontier Fields Galaxy J07173724+3744224,
2018
University of North Dakota
Globular Cluster Population Of The Hst Frontier Fields Galaxy J07173724+3744224, Nathan L. Carlson, Madina R. Sultanova, Sandanuwan P. Kalawila Vithanage, Wayne A. Barkhouse, Gihan L. Ipita Kaduwa Gamage, Cody M. Rude, Omar López-Cruz
Physics Faculty Publications
We present the first measurement of the globular cluster (GC) population surrounding the elliptical galaxy J07173724+3744224 (z" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; vertical-align: baseline; display: inline; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">zz = 0.1546). This galaxy is located in the foreground in the field-of-view of the Hubble Space Telescope (HST) Frontier Fields observations of galaxy cluster MACS J0717.5+3745 (z" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: …
Asymmetric Free-Space Light Transport At Nonlinear Metasurfaces,
2018
The University of Texas Rio Grande Valley
Asymmetric Free-Space Light Transport At Nonlinear Metasurfaces, Nir Shitrit, Jeongmin Kim, David S. Barth, Hamidreza Ramezani, Yuan Wang, Xiang Zhang
Physics & Astronomy Faculty Publications
Asymmetric light transport has significantly contributed to fundamental science and revolutionized advanced technology in various aspects such as unidirectional photonic devices, optical diodes, and isolators. While metasurfaces mold wave fronts at will with an ultrathin flat optical element, asymmetric transport of light cannot be fundamentally achieved by any linear system including linear metasurfaces. We report asymmetric transport of free-space light at nonlinear metasurfaces upon transmission and reflection. Moreover, we theoretically derive the nonlinear generalized Snell's laws that were experimentally confirmed by the anomalous nonlinear refraction and reflection. The asymmetric transport at optically thin nonlinear interfaces is revealed by the concept …
