Bulletin of the American Physical Society
APS April Meeting 2016
Volume 61, Number 6
Saturday–Tuesday, April 16–19, 2016; Salt Lake City, Utah
Session L1: Poster Session II (2:00pm -5:00pm)Poster
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Room: South Foyer |
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L1.00001: ASTROPHYSICS |
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L1.00002: Investigating the Relationship of Luminosity and Curvature Using the Luminous Convolution Model for Spiral Galaxy Rotation Curves Meagan Crowley The Luminous Convolution Model maps velocities of galaxies given by data of visible matter with respect to the relative curvature of the emitter and receiver galaxy using five different models of the Milky Way. This model purports that observations made of the luminous profiles of galaxies do not take the relative curvatures of the emitter and receiver galaxies into account, and thus maps the luminous profile onto the curvature using Lorentz transformations, and then back into the flat frame where local observations are made. The five models of the Milky Way used to compile galaxy data are proposed by Klypin:Anatoly (2002) A and B, Xue (2008), Sofue (2013), and a mixture of Xue and Sofue data. The Luminous Convolution Model has been able to accurately describe the rotation of spiral galaxies through this method without the need for dark matter. In each fitting of a given galaxy, the luminous profile graph exhibits a crossing with the graph of the curvature component, suggesting a correlation between the two. This correlation is currently under investigation as being related to phenomena apparent within each galaxy. To determine the correlation between the luminous profile and the curvature component, a functional analysis of the Luminous Convolution Model will be presented [Preview Abstract] |
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L1.00003: Implications of the Observed Scaling Relations between the Dark Matter Halo Parameters and Half-Light Radii of Milky Way Dwarf Spheroidals Hunter Somers, Zech Miller, Ben Woodall, Casey R. Watson We compare observed scaling relationships between the half-light radii and best-fit, Burkert dark matter halo parameters of 13 Milky Way dwarf spheroidal galaxies (dSphs) to similar relationships found for dwarf spiral galaxies. We also consider the theoretical underpinnings of these relationships and discuss their implications for galaxy formation and evolution. [Preview Abstract] |
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L1.00004: New Explanation of Hubble's Red Shift Dayong Cao The balance system between dark massenergy (with a spacetime center) and stellar massenergy (with a massenergy center) cause a flat universe. In the flat universe, the Hubble$’$s redshift is caused by the Lorentz transformation (Einstein transformation). This paper will discuss about the relationship among Einstein transformation, Doppler effect, and Hubble$’s$ redshift under the balanced and flat universe model. http://meetings.aps.org/link/BAPS.2014.APR.Y9.1 [Preview Abstract] |
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L1.00005: On the electron-positron cascade in AGN central engines Alex Ford, Brett Keenan, Mikhail Medvedev Processes around spinning supermassive black holes (BH) in active galactic nuclei (AGN) are believed to determine how relativistic jets are launched and how the BH energy is extracted. The key "ingredient" is the origin of plasma in BH magnetospheres. In order to explore the process of the electron-positron plasma production, we developed a numerical code which models a one-dimensional (along a magnetic field line) dynamics of the cascade. Our simulations show that plasma production is controlled by the spectrum of the ambient photon field, the B-field strength, the BH spin and mass. Implications of our results to the Galactic Center and AGNs are discussed. [Preview Abstract] |
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L1.00006: ABSTRACT WITHDRAWN |
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L1.00007: Bridging the Gap: Characterizing Groups of Galaxies Jason Parisi, Priyamvada Natarajan While galaxies are ubiquitous in the universe, and galaxy clusters, the most massive structures are rare, intermediate mass scale objects - galaxy groups - are abundant. However, their properties are not as well studied at present, partly due to the difficulty in characterizing them and their dynamics. Besides, they are likely transitory objects that eventually merge into assembling clusters. Galaxy groups therefore offer an interesting laboratory to study dynamical processes as well as to probe the interplay between baryons and dark matter. We present the first results from a galaxy group finder algorithm that selects candidates from the large high-resolution cosmological Illustris simulation with a view to better understand their formation, and to more accurately characterize them as a class of astrophysical objects. Fundamental relations between galaxy groups and their dark matter substructure, their member galaxies, and other observables are characterized. We compare the current observational classification of galaxy groups - compact, fossil, and loose - with correlations recovered from simulations, and propose new criteria to describe galaxy groups. Preliminary Illustris findings are compared with multi-wavelength observational findings. [Preview Abstract] |
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L1.00008: On the regimes of thermal conduction in IGM plasmas Mikhail Medvedev Clusters of galaxies are the largest gravitationally bound systems of the universe, hence they are superior cosmological probes. For instance, observations of Bremsstrahlung emission from the gas in galaxy clusters help us deduce their masses and constrain certain cosmological parameters. The latter is not perfect, however. Particularly, thermal conduction in the intergalactic medium (IGM) is thought to play crucial role in plasma dynamics but its value is debated. Unlike collisional plasmas, energy transport in magnetized collisionless or weakly collisional plasmas of the IGM exhibits various regimes with vastly different values of the thermal conduction coefficient. Here we discuss these regimes and their implication for galaxy cluster physics. [Preview Abstract] |
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L1.00009: Exploring the Effects of Clump Geometry on Supernova Spectropolarimetry Lance Ostby, Tabetha Hole Observations have previously detected polarization in all types of supernovae. One possible source for the variation in polarization across spectral lines is an inhomogeneous chemical structure of the ejecta. Our purpose is to investigate the statistical association of host configuration with observational signatures. Since this requires a large set of simulated ejecta, our code uses depolarizing resonant scattering in absorption lines to calculate Stokes spectra for each of thousands of randomly distributed realizations of these inhomogeneities (also called ``clumps''). By varying parameters of these clumps, we can predict effects of specific clump geometries and host configurations on observations. Here we present the results of simulations of a newly-implemented shell-like clump geometry and compare them with those of previous simulations. These results, when compared with observations, can provide insight into the structure of chemical inhomogeneities in supernovae. [Preview Abstract] |
(Author Not Attending)
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L1.00010: Fast Radio Bursts and Radio Transients from Black Hole Batteries Chiara Mingarelli, Janna Levin, Joseph Lazio Most black holes (BHs) will absorb a neutron star (NS) companion fully intact, without tidal disruption, suggesting the pair will remain dark to telescopes. Even without tidal disruption, electromagnetic (EM) luminosity is generated from the battery phase of the binary when the BH interacts with the NS magnetic field. Originally the luminosity was expected in high-energy X-rays or gamma-rays, however we conjecture that some of the battery power is emitted in the radio bandwidth. While the luminosity and timescale are suggestive of fast radio bursts (FRBs), NS--BH coalescence rates are too low to make these a primary FRB source. Instead, we propose the transients form a FRB sub-population, distinguishable by a double peak. The main burst is from the peak luminosity before merger, while the post-merger burst follows from the NS magnetic field migration to the BH, causing a shock. NS--BH pairs are desirable for ground-based gravitational wave (GW) observatories since the pair might not be detected any other way, with EM counterparts augmenting the scientific leverage beyond the GW signal. Valuably, EM signal can break degeneracies in the parameters encoded in the GW as well as probe the NS magnetic field strength, yielding insights into open problems in NS magnetic field decay. [Preview Abstract] |
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L1.00011: Nucleosynthesis in self-consistent, multi-dimensional simulations of CCSNe J. Austin Harris, W. Raphael Hix, Merek Chertkow, Stephen Bruenn, Eric Lentz, Daniel Kasen Observations of nuclear abundances in core-collapse supernova ejecta, highlighted by $\gamma$-ray observations of the $^{44}$Ti spatial distribution in the nearby supernova remnants Cas A and SN 1987A, allow nucleosynthesis calculations to place powerful constraints on conditions deep in the interiors of supernovae and their progenitor stars. This ability to probe where direct observations cannot makes such calculations an invaluable tool for understanding the CCSN mechanism. Unfortunately, despite knowing for two decades that supernovae are intrinsically multi-dimensional events, discussions of CCSN nucleosynthesis have been predominantly based on spherically symmetric models, which employ a contrived energy source to launch an explosion and often ignore important neutrino effects. As part of the effort to bridge the gap between first-principles simulations of the explosion mechanism and observations of both supernovae and SNRs, we investigate CCSN nucleosynthesis with self-consistent, 2D simulations using a multi-dimensional radiation-hydrodynamics code. We present nucleosynthesis results for several axisymmetric CCSN models models which qualitative differences from their parameterized counterparts in their ejecta composition and spatial distribution. [Preview Abstract] |
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L1.00012: The Impacts of Halo-CMEs on the Ionospheric Critical Frequency foF2 Ramy Mawad, Hussein M. Farid, Shahinaz Yousef We have studied the impact of Halo-CMEs on the ionospheric critical frequency foF2 during the period 1996-2013. We have correlated the monthly maximum values of foF2 with monthly averages of Halo-CME's energy, mass and speed; we found that the correlation coefficient R is 74{\%}, 52{\%} and 65{\%} respectively. This indicates that the energetic, massive and fast Halo-CMEs can affect the ionospheric critical frequency foF2 more efficiently. In addition, the monthly average Halo-CME's width correlates with the monthly maximum foF2 with R\textasciitilde 57{\%}. This implies that as the width of the Halo-CME increases, the possibility of this event to hit the Earth increases and the ionospheric-targeted area increases, thus the foF2 values; as an implication of increasing the ionization of the ionosphere; subsequently increases. [Preview Abstract] |
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L1.00013: A new model of the electron temperature in the topside ionosphere Zahra Panahi Estarkhi, Ali Bakhshayeshi hra Panahi Estarkhi, Ali Bakhshayeshi Young Researchers and Elite club, Mashhad Branch, Islamic Azad University, Mashhad, Iran Department of physics, Mashhad Branch, Islamic Azad University, Mashhad, Iran. By using empirical models of electron density in the ionosphere, height equations as a function of electron density from $\alpha $-Chapman, Epstein and exponential functions have been achieved. Plotting the achieved height equations, the one derived from Epstein function has been known as the best fit for height. Locating height derived from Epstein function in an empirical function for electron temperature, a new empirical model for electron temperature as a function of electron density has been achieved and applied to obtain directly the electron temperature for every electron density in the topside ionosphere. Latitudinal and seasonal variations for Te have been plotted in the heights above hmF2 to 1000km to compare the new Te model with the previous empirical model and the measured data from the ISIS database. The results are compared and the possible reasons for difference and similarities are also discussed. [Preview Abstract] |
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L1.00014: Quasi-collisional Magneto-optic Effects in Collisionless Plasmas Brett Keenan, Alex Ford, Mikhail Medvedev High-amplitude, chaotic/turbulent electromagnetic fluctuations are ubiquitous in astrophysical plasmas, where they can be excited by various kinetic-streaming and/or anisotropy-driven instabilities, such as the Weibel instability. These fields typically exist on ``sub-Larmor scales'' --- scales smaller than the electron Larmor radius. Electrons moving through such magnetic fields undergo small-angle stochastic deflections of their pitch-angles, thus establishing diffusive transport on long time-scales. We show that this behavior, under certain conditions, is equivalent to Coulomb collisions in collisional plasmas. The magnetic pitch-angle diffusion coefficient, which acts as an effective ``collision'' frequency, may be substantial in these, otherwise, collisionless environments. We show that this effect, colloquially referred to as the plasma ``quasi-collisionality'', may radically alter the expected radiative transport properties of candidate plasmas. We argue that the modified magneto-optic effects in these plasmas provide an attractive, novel radiative diagnostic tool for the exploration and characterization of small-scale magnetic turbulence. [Preview Abstract] |
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L1.00015: Poynting jets of force-free plasma: exact solutions and self-confinement Ted Jacobson, Samuel E. Gralla A class of exact, non-axisymmetric, translation invariant force-free Poynting jet solutions will be described. Remarkably, one can generate Poynting flux solutions by applying an arbitrary fieldline-dependent boost to a purely magnetic solution. In the infinite boost limit one obtains "null jets" that have vanishing electromagnetic pressure, so are self-confined without any external pressure.\\ S.E. Gralla and T. Jacobson, Phys. Rev. D 92, 043002 (2015) [Preview Abstract] |
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L1.00016: Investigation of Very Fast Light Detectors: Silicon Photomultiplier and Micro PMT for a Cosmic Ray Array Omar Cervantes, Liliana Reyes, Tyler Hooks, Luis Perez, Stefan Ritt To construct a cosmic detector array using 4 scintillation detectors, we investigated 2 recent light sensor technologies from Hamamatsu, as possible readout detectors. First, we investigated several homemade versions of the multipixel photon counter (MPPC) light sensors. These detectors were either biased with internal or external high voltage power supplies. We made extensive measurements to confirm for the coincidence of the MPPC devices. Each sensor is coupled to a wavelength shifting fiber (WSF) that is embedded along a plastic scintillator sheet (30cmx60cmx1/4''). Using energetic cosmic rays, we evaluated several of these homemade detector modules placed above one another in a light proof enclosure. Next, we assembled 2 miniaturized micro photomultiplier (micro PMT), a device recently marketed by Hamamatsu. These sensors showed very fast response times. With 3 WSF embedded in scintillator sheets, we performed coincidence experiments. The detector waveforms were captured using the 5GS/sec domino ring sampler, the DRS4 and our workflow using the CERN PAW package and data analysis results would be presented. [Preview Abstract] |
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L1.00017: Pauli mechanism for universal expansion. Robert Hayes By assuming the cosmological principle includes the Pauli exclusion principle (PEP) and that existence occurred post big bang within Planck time and length scales, a model for universal expansion can be argued. All Fermionic matter is forced by the PEP to make a quantum transition to minimally orthogonal states scaling with that predicted for a neutron star (NS). This predicts the minimum inflation time scale to be on the order of 1e-44 s. A coupling of primordial low mass neutrinos to have wavelengths comparable to or greater than the Hubble length is also postulated as a contributor to universal expansion. The model provides a mechanistic explanation for universal expansion using only physics from the standard model. This work supported in part under federal grant NRC-HQ-84-14-G-0059. [Preview Abstract] |
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L1.00018: Measuring the Dark Energy Driven Expansion of the Universe at Redshift\textasciitilde 1 Andrea Kueter-Young, John Moustakas In 1998 astronomers made the remarkable discovery that the universe is expanding at an ever-faster rate due to an unknown force or energy field now known as "dark energy." The Dark Energy Spectroscopic Instrument (DESI) survey will measure the accelerating expansion of the universe with unprecedented precision, yielding crucial insights into the physical nature of dark energy. In order to effectively carry out this measurement, however, DESI needs to efficiently select five distinct classes of distant objects from ground-based imaging surveys containing millions of unimportant, interloping extragalactic sources. Focusing on one specific class of objects---star-forming emission-line galaxies---we investigate a variety of Machine Learning algorithms in order to determine which method optimally selects emission-line galaxies. We apply these algorithms to spectroscopic test datasets from the Sloan Digital Sky Survey and the DEEP2 galaxy redshift survey, and use cross-validation to test the effectiveness of each method. We find that the Machine Learning algorithms considered yield a negligible improvement over the traditional, simple method of using color-color cuts to select emission-line galaxies. [Preview Abstract] |
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L1.00019: Dark Matter from Our Probabilistic Gravity Shantilal Goradia We say that the probability of interaction between any two nucleons is inversely proportional to the square of their separation in Planck lengths [1]. If all the nucleons in the universe were lying in a series, the sum of all simultaneous interactions of the first nucleon with the rest of the nucleons in the universe would be less than 1.65, based on Euler’s. In reality, the sum would be more, since the nucleons are not laid that way. Based on the observed abundance of dark stuff, 20 times the luminous matter, each (spooky) nucleon must be interacting with 20 nucleons at the same Planck time, generating 20 times more strong couplings than otherwise expected. Each strong coupling is a black hole like short range force. Since March 1999, our stand is that gravity is a long range manifestation of so called short range forces like strong couplings [2]. Therefore, 20 times more strong couplings will generate 20 times more gravitation as observed by the dark stuff abundance, neglecting the effects of smaller couplings. [1] “Dark Matter from Our Probabilistic Gravity” The Journal of Physical Science and Application 5 (5) (2015) 373 – 376. [2] “Why is Gravity so Weak?” The Journal of Nuclear Radiations and Physics 1: 107 – 17. [Preview Abstract] |
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L1.00020: Vacuum Decay of de Sitter Space Emil Mottola, Paul Anderson, Dillon Sanders de Sitter space is unstable to particle creation, even for a massive free field theory with no self-interactions. The O(4,1) de Sitter invariant state is a definite phase coherent superposition of particle and anti-particle solutions in both the asymptotic past and future, and therefore is not a true vacuum state. The decay rate is studied both analytically and numerically by adiabatically switching on and off of de Sitter background is studied analytically and numerically. Possible consequences for the sensitivity to initial conditions in inflation and a theory of vacuum dark energy are discussed. [Preview Abstract] |
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L1.00021: Simulations of Detectability of Extrasolar Planets by a Joint Doppler and WFIRST-AFTA Coronagraph Survey Ashley Chontos, Bruce Macintosh, Eric Nielsen A long-term goal for the astronomical community is to image and characterize an Earth-like planet. The WFIRST-AFTA space mission will make advancements towards this goal. WFIRST will include a coronagraphic instrument to discover and characterize new exoplanets and to better characterize already known exoplanets. Although the WFIRST coronagraph will be very powerful, mission time to discover new planetary systems is limited. Identifying promising targets in advance could significantly enhance the scientific yield. We present results of simulations using a Doppler survey to find lower mass planets as possible targets for WFIRST. For simulations, simplified completeness estimates (Howard {\&} Fulton 2014) are used to test the sensitivity of a prospective Doppler campaign. We use data from the HARPS spectrograph to determine exposure times needed to achieve 1 m/s uncertainty. Stellar jitter was randomly sampled from a uniform distribution based on spectral type, treating OBA-type, FGK-type, and M-type stars separately. For survey parameters, we use campaign parameters from the WIYN telescope, assuming 10 hours per night at 100 nights per year over 6 years. In any one simulation, we find roughly 45-50 new planets that are potentially observable by WFIRST. By limiting our targets to FGKM type stars within 10 parsecs, we expect one of those planets to be less than 10 Earth masses. [Preview Abstract] |
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L1.00022: Orbital decay of hot Jupiters due to nonlinear tidal dissipation within solar-type hosts Reed Essick, Nevin Weinberg We study the orbital evolution of hot Jupiters due to the excitation and damping of tidally driven g-modes within solar-type host stars. Linearly resonant g-modes (the dynamical tide) are driven to such large amplitudes in the stellar core that they excite a sea of other g-modes through weakly nonlinear interactions. By solving the dynamics of large networks of nonlinearly coupled modes, we show that the nonlinear dissipation rate of the dynamical tide is several orders of magnitude larger than the linear dissipation rate. We find stellar tidal quality factors ${Q}_{*}^{\prime }\;\simeq $ 10^5–10^6 for systems with planet mass ${M}_{p}\geq 0.5{M}_{{\mathrm{J}}}$ and orbital period $P\leq 2\;\mathrm{days},$ which implies that such systems decay on timescales that are small compared to the main-sequence lifetime of their solar-type hosts. According to our results, there are $\simeq 10$ currently known exoplanetary systems, including WASP-19b and HAT-P-36-b, with orbital decay timescales shorter than a Gyr. Rapid, tidally induced orbital decay may explain the observed paucity of planets with ${M}_{p}\geq {M}_{{\mathrm{J}}}$ and $P\lt 2\;\mathrm{days}$ around solar-type hosts and could generate detectable transit-timing variations in the near future. [Preview Abstract] |
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L1.00023: The HAT-P-7 and HAT-P-11 Star-Planet Systems Jennifer Medina, Maria Manrique, Walter Van Hamme Radial velocities and \textit{KEPLER} light curves of the transiting exoplanets HAT-P-7b and HAT-P-11b are analyzed using a general binary star model. The HAT-P-7 system has been a subject of interest due to the irregular orbit of the HAT-P-7b exoplanet with respect to its parent star. HAT-P-7b's orbit has shed light on the diversity of systems that exist in our observable Universe. HAT-P-11 hosts a K type variable star which we were able to analyze with a fourier fit on the light curve data. It is also a host to exoplanet HAT-P-11b which has a slightly inclined orbit. Using our own software, we have calculated the parameters for star-planet pair of HAT-P-7 and HAT-P-11. This presents another way for astronomers to study these complex systems. [Preview Abstract] |
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L1.00024: All hadronic stop quark searches Yagya Joshi We present our latest results on squarks production in fully hadronic final states using proton-proton collision data corresponding to 2.1fb\textasciicircum -1 Run II at 13 TeV collected with the CMS detector at the LHC. We search for squarks that decay directly to neutralinos and top quarks in multi-jet events with large missing momentum. Sensitivity to the potential signal, over a range of scalar-top and neutralino masses is obtained by selecting events into bins with large missing momentum, MT2, the number of bottom quark and all-hadronic top quark selected with a top-quark tagger. [Preview Abstract] |
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L1.00025: Preliminary results of cosmological simulations with flavor-mixed dark matter and baryonic physics Keita Todoroki, Mikhail Medvedev A number of dark matter (DM) candidates are flavor-mixed particles, yet the standard cosmology does not account for flavor-mixing of CDM. In our earlier DM-only N-body simulations, we have found that DM with more than one flavor-mixed component (the "2cDM" model) simultaneously resolves small-scale problems (the substructure, core/cusp and too-big-to-fail problems) while keeping the large-scale structure intact and being with agreement with observational constraints on DM-self-interactions. While DM-only simulations are crucial for unraveling the nature of DM, baryonic physics (star formation, feedback, outflows, etc.) plays an important role and also affects observational predictions. Here we present preliminary results of N-body simulations of the 2cDM with star formation and baryonic feedback. The results indicate that 2cDM model is generally superior than CDM in a number of respects. For instance, it can reconcile the simulated and observed star formation rates without much tuning. [Preview Abstract] |
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L1.00026: Visualizing the gravitational lensing and vortex and tendex lines of colliding black holes Haroon Khan, Geoffery Lovelace Gravitational waves (GW's) are ripples of space and time that are created when the universe unleashes its violent nature in the presence of strong gravity. Merging black holes (BH) are one of the most promising sources of GW's. In order to detect and physically study the GW's emitted by merging BH with ground based detectors such as Advanced LIGO, we must accurately predict how the waveforms look and behave. This can only be done by numerically simulating BH mergers on supercomputers, because all analytical approximations fail near the time of merger. This poster focuses on using these simulations to answer the question of ``What do merging BH look like''? I will present visualizations made using the Spectral Einstein Code (SpEC) and in particular a raytracing lensing code, developed by the SXS Lensing team, that shows how merging BH bend the light around them. I will also present visualizations of the vortex and tendex lines for a binary BH system, using SpEC. Vortex lines describe how an observer will be twisted by the BH and the tendex lines describe how much an observer would be stretched and squeezed. I am exploring how these lines change with time. [Preview Abstract] |
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L1.00027: Making and Testing Hybrid Gravitational Waves from Colliding Black Holes and Neutron Stars Alyssa Garcia, Geoffrey Lovelace The Laser Interferometer Gravitational-wave Observatory (LIGO) is a detector that is currently working to observe gravitational waves (GW) from astronomical sources, such as colliding black holes and neutron stars, which are among LIGO's most promising sources. Observing as many waves as possible requires accurate predictions of what the waves look like, which are only possible with numerical simulations. In this poster, I will present results from new simulations of colliding black holes made using the Spectral Einstein Code (SpEC). In particular, I will present results for extending new and existing waveforms and using an open-source library. To construct a waveform that spans the frequency range where LIGO is most sensitive, we combine inexpensive, post-Newtonian approximate waveforms (valid far from merger) and numerical relativity waveforms (valid near the time of merger, when all approximations fail), making a hybrid GW. This work is one part of a new prototype framework for Numerical INJection Analysis with Matter (Matter NINJA). The complete Matter NINJA prototype will test GW search pipelines' abilities to find hybrid waveforms, from simulations containing matter (such as black hole-neutron star binaries), hidden in simulated detector noise. [Preview Abstract] |
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L1.00028: Hybridizing Gravitationl Waveforms of Inspiralling Binary Neutron Star Systems Torrey Cullen Gravitational waves are ripples in space and time and were predicted to be produced by astrophysical systems such as binary neutron stars by Albert Einstein. These are key targets for Laser Interferometer and Gravitational Wave Observatory (LIGO), which uses template waveforms to find weak signals. The simplified template models are known to break down at high frequency, so I wrote code that constructs hybrid waveforms from numerical simulations to accurately cover a large range of frequencies. These hybrid waveforms use Post Newtonian template models at low frequencies and numerical data from simulations at high frequencies. They are constructed by reading in existing Post Newtonian models with the same masses as simulated stars, reading in the numerical data from simulations, and finding the ideal frequency and alignment to ``stitch'' these waveforms together. [Preview Abstract] |
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L1.00029: An information-theoretic approach to the gravitational-wave burst detection problem E Katsavounidis, R Lynch, S Vitale, R Essick, F Robinet The advanced era of gravitational-wave astronomy, with data collected in part by the LIGO gravitational-wave interferometers, has begun as of fall 2015. One potential type of detectable gravitational waves is short-duration gravitational-wave bursts, whose waveforms can be difficult to predict. We present the framework for a new detection algorithm -- called \textit{oLIB} -- that can be used in relatively low-latency to turn calibrated strain data into a detection significance statement. This pipeline consists of 1) a sine-Gaussian matched-filter trigger generator based on the Q-transform -- known as \textit{Omicron} --, 2) incoherent down-selection of these triggers to the most signal-like set, and 3) a fully coherent analysis of this signal-like set using the Markov chain Monte Carlo (MCMC) Bayesian evidence calculator \textit{LALInferenceBurst} (LIB). We optimally extract this information by using a likelihood-ratio test (LRT) to map these search statistics into a significance statement. Using representative archival LIGO data, we show that the algorithm can detect gravitational-wave burst events of realistic strength in realistic instrumental noise with good detection efficiencies across different burst waveform morphologies. [Preview Abstract] |
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L1.00030: Antimony-Doped Tin Oxide Thin Films Grown by Home Made Spray Pyrolysis Technique Gbadebo Yusuf, Babatunde Keji Babatola, Abdulahi Dimeji Ishola, Ayodeji O. Awodugba Transparent conducting antimony-doped tin oxide (ATO) films have been deposited on glass substrates by home made spray pyrolysis technique. The structural, electrical and optical properties of the ATO films have been investigated as a function of Sb-doping level and annealing temperature. The optimum target composition for high conductivity and low resistivity was found to be 20 wt. {\%} SnSb$_{2}+$90 wt. ATO. Under optimized deposition conditions of 450$^{o}$C annealing temperature, electrical resistivity of 5.2\texttimes 10$^{-4} \quad \Omega $-cm, sheet resistance of 16.4 $\Omega $/sq, average optical transmittance of 86{\%} in the visible range, and average optical band-gap of 3.34eV were obtained. The film deposited at lower annealing temperature shows a relatively rough, loosely bound slightly porous surface morphology while the film deposited at higher annealing temperature shows uniformly distributed grains of greater size. Keywords: Annealing, Doping, Homemade spray pyrolysis, Tin oxide, Resistivity [Preview Abstract] |
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L1.00031: The Aurora: Electron Transport in the Upper Atmosphere Mark Woods A new approach for solving the electron transport equation in the upper atmosphere is given. A simplified problem is solved exactly, ensuring the numerical solution is correct. The method is used to solve the electron transport problem, given a solar wind distribution. Albedos, scattering rates, and energy deposition are calculated. [Preview Abstract] |
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L1.00032: Contributions to Crustal Mechanics on Europa from Subterranean Ocean Vibrations. Robert Hayes The recent discovery of subduction zones on Europa demonstrated a significant step forward in understanding the moon's surface mechanics. This work promotes the additional consideration that the surface mechanics have contributions from small relative pressure differentials in the subsurface ocean that create cracks in the surface which are then filled, sealed and healed. Crack formation can be small, as interior pressure can relatively easily breach the surface crust, generating cracks followed by common fracture formation backfilled with frozen liquid. This process will slowly increase the overall surface area of the moon with each sealed crack and fracture increasing the total surface area. This creeping growth of surface area monotonically decreases subsurface pressure which can eventually catastrophically subduct large areas of surface and so is consistent with current knowledge of observational topology on Europa. This tendency is attributed to a relatively lower energy threshold to crack the surface from interior overpressures, but a higher energy threshold to crush the spherical surface due to subsurface underpressures. Proposed mechanisms for pressure differentials include tidal forces whose Fourier components build up the resonant oscillatory modes of the subsurface ocean creating periodic under and overpressure events below the crust. This mechanism provides a means to continually reform the surface of the moon over short geological time scales. [Preview Abstract] |
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L1.00033: Modeling Energetic O$^{\mathrm{+}}$ Ions Interacting with Titan's Atmosphere Michael Smith, Theodore Jimsom, Darci Snowden Energetic particles from Saturn's magnetosphere enter Titan's atmosphere where they heat, ionize, and dissociate neutral atoms. This process affects the chemistry of Titan's atmosphere, and is related to the energy deposited by incident energetic particles. Unfortunately, the various ways in which energetic particles, and in particular, O$^{\mathrm{+}}$ ions, enter and interact with the atmosphere have been largely unexplored by computational models despite a plethora of measured data from Cassini flybys. In an effort to investigate energetic particle behavior, a 3D model of O$^{\mathrm{+}}$ ions in Titan's magnetosphere was created to simulate how ions might enter the atmosphere. Using these simulations, we were able to measure power flux across the surface of Titan's atmosphere. Ions that entered the atmosphere, characterized by their initial energy and angle of incidence, were tracked as they deposited their energy into the atmosphere through interactions with neutral N$_{\mathrm{2}}$ molecules. Initial results indicate approximately 5{\%} of starting particles passed into the atmosphere, achieving an average energy flux of approximately 2\textbullet 10$^{\mathrm{9\thinspace }}$eV\textbullet cm$^{\mathrm{-2}}$\textbullet s$^{\mathrm{-1}}$. Further, a maximum energy deposition between 10-50 eV occurs at an altitude of 1300 km, with the distribution of particles' incident angles centered around 50-60\textdegree . [Preview Abstract] |
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L1.00034: Characterization of carbonaceous meteoritic fragments found in Antarctica by high-resolution Raman spectroscopy and SEM/EDS Analia Dall Asen, Brandon Baer, Jake Mittelstaedt, Jordan Gerton, Benjamin Bromley, Scott Kenyon Carbonaceous chondritic meteorites are composed mainly of chondrules (micro/millimeter-sized inclusions) surrounding by a matrix of microparticles, and are considered the most primitive surviving materials from the early Solar System. Understanding their properties and history may provide clues to the formation of planets from micron-size dust grains in the Solar nebula. Our approach is to study the structure and composition of carbonaceous chondrites with high-resolution micro-Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. These techniques enable us to capture details on a wide range of spatial scales, from micrometers to millimeters. Here we provide the first analysis of a set of meteorite fragments from Antarctica (MIL~07002 and ALH~84028), mapping elemental and molecular abundances, as well as large-scale morphological features. We present characterizations of individual chondrules and the surrounding matrix, and we consider on how our findings reflect physical processes believed to be operating during the early stages of planet formation. [Preview Abstract] |
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L1.00035: ABSTRACT MOVED TO T1.00060 |
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L1.00036: Fractal Signals {\&} Space-Time Cartoons Jakob OETAMA,Dr-HC, WH- Maksoed In ``Theory of Scale Relativity'', 1991- L. Nottale states whereas ''scale relativity is a geometrical {\&} fractal space-time theory''. It took in comparisons to ``a unified, wavelet based framework for efficiently synthetizing, analyzing $\backslash $7 processing several broad classes of fractal signals''-Gregory W. Wornell:''Signal Processing with Fractals'', 1995. Furthers, in Fig 1.1. a simple waveform from statistically scale-invariant random process[ \textit{ibid., }h 3 ]. Accompanying RLE Technical Report 566 ``Synthesis, Analysis {\&} Processing of Fractal Signals'' as well as from Wornell, Oct 1991 herewith intended to deducts $=$a $\Delta $t $+$ (1 -- $\beta \quad \Delta $t ) \textellipsis in Petersen, \textit{et.al }:'' \textbf{Scale invariant properties of public debt growth'', }2010 h. 38006p2 to [1/\textbraceleft 1- (2$\alpha (\lambda )$/3$\pi )$ ln ($\lambda $/r)\textbraceright depicts in Laurent Nottale,1991, h 24. [Preview Abstract] |
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L1.00037: Application of Wavelet Packet Analysis to the Measurement of the Baryon Acoustic Oscillation Kevin Kadowaki, Noel Garcia, Taurean Ford, Jesus Pando We develop a method of wavelet packet analysis to measure the Baryon Acoustic Oscillation (BAO) peak and apply this method to the CMASS galaxy catalog from the SDSS Baryon Oscillation Spectroscopic Survey (BOSS) collaboration. We compare our results to a fiducial ?CDM flat cosmological model and detect a BAO signature in the power spectrum comparable to the previous consensus results of the BOSS collaboration. We find $D_A = 1365 r_d/r_{d,fid}$ at $z = .54$. [Preview Abstract] |
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L1.00038: New Constraints on Cosmic-Ray Propagation Models using Hydrogen and Helium Isotope Measurements from the BESS-Polar II Experiment Nicolas Picot-Clemente Deuterium $^2H$ and Helium 3 $^3He$ cosmic rays are mainly secondary particles produced by the spallation of Helium 4 nuclei ($^4He$), or by the fusion of Hydrogen $^1H$, after interacting in the interstellar medium during their propagation. As for the well-known Boron-to-Carbon ratio B/C, the secondary-to-primary ratios of $^2H/^1H$, $^2H/^4He$ and $^3He/^4He$ bring essential information to better understand the propagation of cosmic rays in the Galaxy. BESS-Polar II is a balloon-borne experiment that flew over Antarctica during the 23rd solar cycle minimum in December 2007 through January 2008 for 24.5 days. The instrument is a superconducting magnet spectrometer made of multiple particle detectors capable of precisely separating hydrogen and helium isotopes from 0.2 GeV/nucleon to 1.5 GeV/nucleon. The latest isotope measurements from BESS-Polar II, which are the most precise to date, will be presented and compared to other experiments. The GALPROP program will be used to emphasize the new constraints that these results bring on propagation models and parameters. [Preview Abstract] |
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L1.00039: GRAVITATION |
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L1.00040: Simulation of a black hole laser in a Bose-Einstein condensate Ted Jacobson, Yi-Hsieh Wang, Mark Edwards, Charles W. Clark In a recent experiment [1], J. Steinhauer generated a black/white hole analog by sweeping a potential step through a quasi-one-dimensional Bose-Einstein condensate, and observed behavior that he proposed could be identified as the black hole laser instability and associated Hawking radiation [2]. We have simulated this experiment using the Gross-Pitaevskii (GP) evolution equation for the condensate wave function. The simulation agrees well with the reported experimental results, indicating that the observed behavior can be largely understood at the "hydrodynamic" level of the GP wavefunction. We also identify modified parameters for the experiment which could show a more pronounced signal of the Hawking radiation.\\ \vskip 2mm \noindent [1] J. Steinhauer, Nature Phys. 10, 864 (2014)\\ [2] S. Corley and T. Jacobson, Phys.Rev. D59 (1999) 124011 [Preview Abstract] |
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L1.00041: Modeling Thermal Noise from Crystaline Coatings for Gravitational-Wave Detectors Nicholas Demos, Geoffrey Lovelace The sensitivity of current and future ground-based gravitational-wave detectors are, in part, limited in sensitivity by Brownian and thermoelastic noise in each detector’s mirror substrate and coating. Crystalline mirror coatings could potentially reduce thermal noise, but thermal noise is challenging to model analytically in the case of crystalline materials. Thermal noise can be modeled using the fluctuation-dissipation theorem, which relates thermal noise to an auxiliary elastic problem. In this poster, I will present results from a new code that numerically models thermal noise by numerically solving the auxiliary elastic problem for various types of crystalline mirror coatings. The code uses a finite element method with adaptive mesh refinement to model the auxiliary elastic problem which is then related to thermal noise. I will present preliminary results for a crystal coating on a fused silica substrate of varying sizes and elastic properties. This and future work will help develop the next generation of ground-based gravitational-wave detectors. [Preview Abstract] |
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L1.00042: Parameter Estimation of Binary Neutron Stars using an Effective One Body Model including Tidal Interaction Monica Rizzo, Richard O'Shaughnessy, Sebastiano Bernuzzi, Benjamin Lackey Ground gravitational wave detectors, built to detect perturbations in spacetime, can pick up signals produced by inspiraling binary neutron stars, the remnants of the core collapse of massive stars. A new EOB model (Bernuzzi et al 2015) simulates the inspiral and merger of binary neutron star systems, including how they are deformed due to tides.We used a Bayesian parameter estimation algorithm to infer how well a plausible gravitational wave detection would allow us to constrain this tidal deformability. We then compared our results to prior investigations (Wade et al 2014) which employed a post-Newtonian-based approximation for the inspiral. [Preview Abstract] |
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L1.00043: Identifying Contributing Harmonics in the Gravitational Wave Spectrum of Highly Eccentric EMRIs. Andrew Kaiser, Jordan Stone, Sloan Ahrens, Daniel Kennefick In the study of gravitational waves emitted from extreme mass ratio inspirals highly eccentric orbits are problematic because of the large number of harmonics, and thus the lengthy computation times that were thought to be inherent to it. The issue however, is made simpler because the spectrum is not that broad and is fairly localized. The true complexity lies in finding the peaks of the largest contributors to accurately describe the complete spectrum, since for any given multipole of the spectrum the position of the peak in the emission is difficult to predict. This project uses two methods of finding the peak harmonic of a given spectrum. The first method uses a skipping algorithm to systematically jump over harmonics with insignificant contributions to the total waveform. Because this method is still not completely efficient, a second method uses a Newtonian order approximation given by Peters and Matthews to give an estimate of the frequency of the actual waveform peak, and then fills in around this harmonics to give the spectrum. The two methods are complementary since the skipping algorithm can be used when the Newtonian estimation fails to find the peak immediately. [Preview Abstract] |
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L1.00044: ABSTRACT WITHDRAWN |
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L1.00045: Comparing numerical and analytic approximate gravitational waveforms Nousha Afshari, Geoffrey Lovelace A direct observation of gravitational waves will test Einstein's theory of general relativity under the most extreme conditions. The Laser Interferometer Gravitational-Wave Observatory, or LIGO, began searching for gravitational waves in September 2015 with three times the sensitivity of initial LIGO. To help Advanced LIGO detect as many gravitational waves as possible, a major research effort is underway to accurately predict the expected waves. In this poster, I will explore how the gravitational waveform produced by a long binary-black-hole inspiral, merger, and ringdown is affected by how fast the larger black hole spins. In particular, I will present results from simulations of merging black holes, completed using the Spectral Einstein Code (black-holes.org/SpEC.html), including some new, long simulations designed to mimic black hole-neutron star mergers. I will present comparisons of the numerical waveforms with analytic approximations. [Preview Abstract] |
(Author Not Attending)
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L1.00046: Gravitational-wave cosmology across 29 decades in frequency Chiara Mingarelli, Paul Lasky, Tristan Smith, John T. Giblin, Eric Thrane, Daniel Reardon, Robert Caldwell We derive constraints on the spectrum of the primordial gravitational wave background, and hence on theories of the early Universe, by combining experiments that cover 29 orders of magnitude in frequency. These include Planck observations of cosmic microwave background (CMB) temperature and polarization power spectra and lensing, together with baryon acoustic oscillations and big bang nucleosynthesis measurements, and new pulsar timing array and ground-based interferometer limits. The combination of experiments allows us to constrain cosmological parameters, including the inflationary spectral index, $n_t$, and the tensor-to-scalar ratio, $r$. Results from individual experiments include a stringent nanohertz limit of the primordial background from the Parkes Pulsar Timing Array, $\Omega_\gw(f)<2.3\times10^{-10}$. Observations of the CMB alone limit the gravitational-wave spectral index at 95\% confidence to $n_t\lesssim5$ for a tensor-to-scalar ratio of $r = 0.11$. However, the combination of all the above experiments limits $n_t<0.36$. Future Advanced LIGO observations are expected to further constrain $n_t<0.34$ by 2020. When CMB experiments detect a non-zero $r$, our results will imply even more stringent constraints on $n_t$ and hence theories of the early Universe. [Preview Abstract] |
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L1.00047: Modeling Binary Neutron Stars Conner Park, Jocelyn Read, Eric Flynn, Veronica Lockett-Ruiz Gravitational waves, predicted by Einstein's Theory of Relativity, are a new frontier in astronomical observation we can use to observe phenomena in the universe. Laser Interferometer Gravitational wave Observatory (LIGO) is currently searching for gravitational wave signals, and requires accurate predictions in order to best extract astronomical signals from all other sources of fluctuations. The focus of my research is in increasing the accuracy of Post-Newtonian models of binary neutron star coalescence to match the computationally expensive Numerical models. Numerical simulations can take months to compute a couple of milliseconds of signal whereas the Post-Newtonian can generate similar signals in seconds. However the Post-Newtonian model is an approximation, e.g. the Taylor T4 Post-Newtonian model assumes that the two bodies in the binary neutron star system are point charges. To increase the effectiveness of the approximation, I added in tidal effects, resonance frequencies, and a windowing function. Using these observed effects from simulations significantly increases the Post-Newtonian model's similarity to the Numerical signal. [Preview Abstract] |
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L1.00048: Wormhole geometries in fourth-order conformal Weyl gravity. Gabriele Varieschi, Kellie Ault We present an analysis of the classic wormhole geometries based on conformal Weyl gravity, rather than standard general relativity. The main characteristics of the resulting traversable wormholes remain the same as in the seminal study by Morris and Thorne, namely, that effective super-luminal motion is a viable consequence of the metric. Improving on previous work on the subject, we show that for particular choices of the shape and redshift functions, the wormhole metric in the context of conformal gravity does not violate the main energy conditions, as was the case of the original solutions. In particular, the resulting geometry does not require the use of exotic matter at or near the wormhole throat. Therefore, if fourth-order conformal Weyl gravity is a correct extension of general relativity, traversable wormholes might become a realistic solution for interstellar travel. [Preview Abstract] |
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L1.00049: A Generalization of the Einstein-Maxwell Equations Fredrick Cotton The proposed modifications of the Einstein-Maxwell equations include: (1) the addition of a scalar term to the electromagnetic side of the equation rather than to the gravitational side, (2) the introduction of a 4-dimensional, nonlinear electromagnetic constitutive tensor and (3) the addition of curvature terms arising from the non-metric components of a general symmetric connection. The scalar term is defined by the condition that a spherically symmetric particle be force-free and mathematically well-behaved everywhere. The constitutive tensor introduces two auxiliary fields which describe the particle structure. The additional curvature terms couple both to particle solutions and to electromagnetic and gravitational wave solutions. http://sites.google.com/site/fwcotton/em-30.pdf [Preview Abstract] |
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L1.00050: On an Axial-Vector Gravity Rasulkhozha S. Sharafiddinov The nature itself unites all of C-even gauge bosons in gravitons of C-invariance [1]. Thereby, it requires the classification of elementary particles and currents with respect to C-operation [2]. This procedure in turn admits the existence of gauge bosons of true neutrality [3]. To them apply the weak $Z^{0}(W^{0})$-bosons, axial-vector photons $(\gamma^{A})$ and the others of a set of mediate bosons of C-noninvariant types of interactions of nonweak and unknown properties. They constitute herewith the gravitons of C-noninvariance, confirming that we cannot exclude the existence of an axial-vector gravity, which comes forward in the universe as a grand unification of all types of forces of a C-noninvariant nature. [1] R.S. Sharaiddinov, Bull. Am. Phys. Soc. 60(4), E13.00008 (2015). [2] R.S. Sharafiddinov, Bull. Am. Phys. Soc. 57(16), KA.00069 (2012). [3] R.S. Sharafiddinov, Bull. Am. Phys. Soc. 59(18), JP.00046 (2014). [Preview Abstract] |
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L1.00051: Derivation of Einstein--Cartan theory from general relativity Richard Petti This article presents a derivation of Einstein--Cartan theory from general relativity with no additional assumptions or parameters. The derivation begins with distributions of Kerr masses that converge to a continuum with constant densities of mass, momentum, and angular momentum. The limit includes torsion and the spin-torsion relationship of Einstein--Cartan theory. The construction of curvature and torsion is equivalent to definition of curvature with Cartan forms on fiber bundles. Advantages of Einstein--Cartan theory include accommodating exchange of classical intrinsic and orbital angular momentum and generation of inflation-like expansion in high density cosmological models. [Preview Abstract] |
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L1.00052: Nuclear Quantum Gravitation -- The Correct Theory. Ronald Kotas Nuclear Quantum Gravitation provides a clear, definitive Scientific explanation of Gravity and Gravitation. It is harmonious with Newtonian and Quantum Mechanics, and with distinct Scientific Logic. Nuclear Quantum Gravitation has 10 certain, Scientific proofs and 21 more good indications. With this theory the Physical Forces are obviously Unified. See: OBSCURANTISM ON EINSTEIN GRAVITATION? \underline {http://www.santilli}- Foundation.org/inconsistencies-gravitation.php and Einstein's Theory of Relativity versus Classical Mechanics \underline {http://www.newtonphysics.on.ca/einstein/} [Preview Abstract] |
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L1.00053: ABSTRACT WITHDRAWN |
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L1.00054: To Rabi Hamiltonian through their Time Dependent Terms can be Reckons as Fractals Glory Rosary-OYONG,SE For light-matters interactions, ever replies by theLate HE. Mr. Prof M. Barmawi through Bose-Einstein condensates matter-waves ever retrieves [Boyce {\&} DiPrima, 2015] instead of Richard Courant cq HE. Mr. Prof. Sudjoko Danusubroto's LKTM, Lustrum VI ITB, March 2, 1984. Follows ``Modified kernel to Quantum systems thorough Laplace inverse transformation'' whereas ``karyon'' in prokaryotes/eukaryotes meant as well as `kernel' , have been sought for `growth curve' {\&} `potential of proton to other protons' the time dependent terms cos ($\omega $t)exp[-i$\omega_{\mathrm{o}}$t] whose integration y $=$ sin $\omega $t $+$ c proves to be fractals \textless atomlight.pdf\textgreater h. 3 guided by Rabi Hamiltonian from Isidor Isaac Rabi,1944. Accompanying ``the Theory of Scale Relativity'' from Laurent Nottale/LUTH, the proofs of considerances whereas `time also are fractals', from Norways for Infra OMAN soughts a benchmark portfolio from Kjell Storvik, 2004:\textbf{''Socially Responsible Investment Strategies for the Norwegian Petroleum Fund'' }whereas the Rabi frequency ? $=$ 2 $\varepsilon $.d$_{\mathrm{eg}}$/h can be relatively in comparisons expressed of capacitive [E.d/h]. [Preview Abstract] |
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L1.00055: Gravitational Radiation in the Relativistic Theory of Gravitation. Stanislav Fisenko, Igor Fisenko The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is~based on theoretically proved and experimentally confirmed fact of existence of stationary states of an electron in its gravitational field characterized by the gravitational constant K $=$ 10$^{\mathrm{42}}$G (G is the Newtonian gravitational constant) and unrecoverable space-time curvature $\Lambda $. If the numerical values of $K \quad \approx $ 5.1\texttimes 10$^{\mathrm{31}}$ Nm$^{\mathrm{2}}$kg$^{\mathrm{-2\thinspace }}$ and $\Lambda $ $=$4.4\texttimes 10$^{\mathrm{29}}$ m$^{\mathrm{-2}}$ , there is a spectrum of stationary states of the electron in its own gravitational field (0.511 MeV ... 0.681 MeV). Adjusting according to the known mechanisms of broadening does not disclose the broadening of the registered portion of the emission spectrum of the micropinch. It indicates the presence of an additional mechanism of broadening the registered portion of the spectrum of the characteristic radiation due to the contribution of the excited states of electrons in their own gravitational field. The energy spectrum of the electron in its own gravitational field and the energy spectra of multielectron atoms are such that there is a resonance of these spectra. As obvious, the consequence of such resonant interaction is appearance, including new lines, of electromagnetic transitions not associated with atomic transitions. The obtained results perhaps also explain the physical nature of spin as the angular momentum in its own gravitational field and the known ambiguity in the results of measuring the size of a proton by different methods. [Preview Abstract] |
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L1.00056: Performance of the Prototype Readout System for the CMS Endcap Hadron Calorimeter Upgrade Nate Chaverin, Jay Dittmann, Kenichi Hatakeyama, Nathaniel Pastika The Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Collider (LHC) will upgrade the photodetectors and readout systems of the endcap hadron calorimeter during the technical stop scheduled for late 2016 and early 2017. A major milestone for this project was a highly successful testbeam run at CERN in August 2015. The testbeam run served as a full integration test of the electronics, allowing a study of the response of the preproduction electronics to the true detector light profile, as well as a test of the light yield of various new plastic scintillator materials. We present implications for the performance of the hadron calorimeter front-end electronics based on testbeam data, and we report on the production status of various components of the system in preparation for the upgrade. [Preview Abstract] |
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L1.00057: Alpha Background Rejection in Bolometer Detectors Nicholas DePorzio This study presents the modification of bolometer detectors used in particle searches to veto or otherwise reject alpha radiation background and the statistical advantages of doing so. Several techniques are presented in detail -- plastic film scintillator vetoes, metallic film ionization vetoes, and scintillating bolometer vetoes. Plastic scintillator films are cooled to bolometer temperatures and bombarded with 1.4MeV to 6.0MeV alpha particles representative of documented detector background. Photomultipliers detect this scintillation light and produce a veto signal. Layered metallic films of a primary metal, dielectric, and secondary metal, such as gold-polyethylene-gold films, are cooled to milli-kelvin temperatures and biased to produce a current signal veto when incident 1.4MeV to 6.0MeV alpha particles ionize conduction paths through the film. Modified Zinc Molybdate Bolometers are used to produce scintillation light when stimulated by alpha background. Calibration of veto signal to background energy is presented. Results are used to quantify the statistical impact of such modifications on bolometer searches. [Preview Abstract] |
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L1.00058: Orbiting radiation Stars Gabe Perez-Giz, Dean Foster, John Langford We study a spherically symmetric solution to the Einstein equations in which the source, which we call an orbiting radiation star (OR-star), is a compact object consisting of freely-falling null particles. The solution avoids quantum scale regimes and hence neither relies upon nor ignores the interaction of quantum mechanics and gravitation. The OR-star spacetime exhibits a deep gravitational well yet remains singularity free. In fact, it is geometrically flat in the vicinity of the origin, with the flat region being of any desirable scale. The solution is observationally distinct from a black hole because a photon from infinity aimed at an OR-star escapes to infinity with a time delay. [Preview Abstract] |
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L1.00059: Developing PYTHON Codes for the Undergraduate ALFALFA Team Parker Troischt, Nicholas Ryan ~We describe here progress toward developing a number of new PYTHON routines to be used by members of the Undergraduate ALFALFA Team.~ The codes are designed to analyze HI spectra and assist in identifying and categorizing some of the intriguing sources found in the initial blind ALFALFA survey.~ Numerical integration is performed on extragalactic sources using 21cm line spectra produced with the L-Band Wide receiver at the National Astronomy and Ionosphere Center.~ Prior to the integration, polynomial fits are employed to obtain an appropriate baseline for each source.~ The codes developed here are part of a larger team effort to use new PYTHON routines in order to replace, upgrade, or supplement a wealth of existing IDL codes within the collaboration.~ [Preview Abstract] |
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