Open Access. Powered by Scholars. Published by Universities.®

Cosmology, Relativity, and Gravity Commons™

Open Access. Powered by Scholars. Published by Universities.®

Embry-Riddle Aeronautical University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 61 - 90 of 93

Full-Text Articles in Cosmology, Relativity, and Gravity

Observation Of Gravitational Waves From A Binary Black Hole Merger, B. P. Abbott, K. Gill, B. Hughey, M, J. Szczepańczyk, M. Zanolin, Et Al. Feb 2016

Observation Of Gravitational Waves From A Binary Black Hole Merger, B. P. Abbott, K. Gill, B. Hughey, M, J. Szczepańczyk, M. Zanolin, Et Al.

Publications

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10−21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater …

Go to article

Gravitons To Photons--Attenuation Of Gravitational Waves, Preston Jones, Douglas Singleton Nov 2015

Gravitons To Photons--Attenuation Of Gravitational Waves, Preston Jones, Douglas Singleton

Publications

In this essay, we examine the response of an Unruh–DeWitt (UD) detector (a quantum two-level system) to a gravitational wave background. The spectrum of the UD detector is of the same form as some scattering processes or three body decays such as muon-electron scattering or muon decay. Based on this similarity, we propose that the UD detector response implies a “decay” or attenuation of gravitons, G, into photons, γ, via G+G→γ+γ or G→γ+γ+G. Over large distances such a decay/attenuation may have consequences in regard to the detection of gravitational waves.

Go to article

Testing Lorentz Symmetry With Planetary Orbital Dynamics, A. Hees, Q. G. Bailey, C. Le Poncin-Lafitte, A. Bourgoin, A. Rivoldini, B. Lamine, F. Meynadier, C. Guerlin, P. Wolf Sep 2015

Testing Lorentz Symmetry With Planetary Orbital Dynamics, A. Hees, Q. G. Bailey, C. Le Poncin-Lafitte, A. Bourgoin, A. Rivoldini, B. Lamine, F. Meynadier, C. Guerlin, P. Wolf

Publications

Planetary ephemerides are a very powerful tool to constrain deviations from the theory of general relativity (GR) using orbital dynamics. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In this communication, we use the latest determinations of the supplementary advances of the perihelia and of the nodes obtained by planetary ephemerides analysis to constrain SME coefficients from the pure gravity sector and also from gravity-matter couplings. Our results do not show any deviation from GR and …

Go to article

What Do We Know About Lorentz Symmetry?, Q. G. Bailey Mar 2015

What Do We Know About Lorentz Symmetry?, Q. G. Bailey

Publications

Precision tests of Lorentz symmetry have become increasingly of interest to the broader gravitational and high-energy physics communities. In this talk, recent work on violations of local Lorentz invariance in gravity is discussed, including recent analysis constraining Lorentz violation in a variety of gravitational tests. The arena of short-range tests of gravity is highlighted, demonstrating that such tests are sensitive to a broad class of unexplored signals that depend on sidereal time and the geometry of the experiment.

Go to article

Short-Range Gravity And Lorentz Violation, Quentin G. Bailey, V. Alan Kostelecký, Rui Xu Jan 2015

Short-Range Gravity And Lorentz Violation, Quentin G. Bailey, V. Alan Kostelecký, Rui Xu

Publications

Comparatively few searches have been performed for violations of local Lorentz invariance in the pure-gravity sector. We show that tests of short-range gravity are sensitive to a broad class of unconstrained and novel signals that depend on the experimental geometry and on sidereal time.

Go to article

Quantum Tests Of The Einstein Equivalence Principle With The Ste-Quest Space Mission, Brett Altschul, Quentin G. Bailey, Luc Blanchet, Kai Bongs, Philippe Bouyer, Luigi Cacciapuoti, Et Al. Jan 2015

Quantum Tests Of The Einstein Equivalence Principle With The Ste-Quest Space Mission, Brett Altschul, Quentin G. Bailey, Luc Blanchet, Kai Bongs, Philippe Bouyer, Luigi Cacciapuoti, Et Al.

Publications

We present in detail the scientific objectives in fundamental physics of the Space–Time Explorer and QUantum Equivalence Space Test (STE–QUEST) space mission. STE–QUEST was pre-selected by the European Space Agency together with four other missions for the cosmic vision M3 launch opportunity planned around 2024. It carries out tests of different aspects of the Einstein Equivalence Principle using atomic clocks, matter wave interferometry and long distance time/frequency links, providing fascinating science at the interface between quantum mechanics and gravitation that cannot be achieved, at that level of precision, in ground experiments. We especially emphasize the specific strong interest of performing …

Go to article

The Link Between Shocks, Turbulence And Magnetic Reconnection In Collisionless Plasmas, H. Karimabadi, V. Roytershteyn, H. X. Vu, Y. Omelchenko, J. Scudder, W. Daughton, A. Dimmock, Katariina (Heidi) Nykyri, Et Al. Apr 2014

The Link Between Shocks, Turbulence And Magnetic Reconnection In Collisionless Plasmas, H. Karimabadi, V. Roytershteyn, H. X. Vu, Y. Omelchenko, J. Scudder, W. Daughton, A. Dimmock, Katariina (Heidi) Nykyri, Et Al.

Publications

Global hybrid (electron fluid, kinetic ions) and fully kinetic simulations of the magnetosphere have been used to show surprising interconnection between shocks, turbulence and magnetic reconnection. In particular collisionless shocks with their reflected ions that can get upstream before retransmission can generate previously unforeseen phenomena in the post shocked flows: (i) formation of reconnecting current sheets and magnetic islands with sizes up to tens of ion inertial length. (ii) Generation of large scale low frequency electromagnetic waves that are compressed and amplified as they cross the shock. These 'wavefronts' maintain their integrity for tens of ion cyclotron times but eventually …

Go to article

Book Review: Cosmic Dawn: The Search For The First Stars And Galaxies, T. D. Oswalt Apr 2014

Book Review: Cosmic Dawn: The Search For The First Stars And Galaxies, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Cosmic Dawn : the Search for the First Stars and Galaxies by George Rhee, springer, 2013. 279p, 9781461478126 $39.99, 9781461478133 $29.99.

Go to article

Local Lorentz-Symmetry Breaking And Gravity, Q. G. Bailey Mar 2014

Local Lorentz-Symmetry Breaking And Gravity, Q. G. Bailey

Publications

The lagrangian-based Standard-Model Extension framework offers a broad description of possible gravitational effects from local Lorentz violation. In this talk, I review the status of the theoretical and phenomenological work in this area. The extension of previous results in linearized gravity to the nonlinear regime is discussed.

Go to article

Constraints On Violations Of Lorentz Symmetry From Gravity Probe B, James M. Overduin, Ryan D. Everett, Quentin G. Bailey Mar 2014

Constraints On Violations Of Lorentz Symmetry From Gravity Probe B, James M. Overduin, Ryan D. Everett, Quentin G. Bailey

Publications

We use the final results from Gravity Probe B to set new upper limits on the gravitational sector of the Standard-Model Extension, including for the first time the coefficient associated with the time-time component of the new field responsible for inducing local Lorentz violation in the theory.

Go to article

Long-Range Propagation, Interaction, And Dissipation Of Small-Scale Gravity Waves In The Mesosphere And Lower Thermosphere, Christopher J. Heale Jan 2014

Long-Range Propagation, Interaction, And Dissipation Of Small-Scale Gravity Waves In The Mesosphere And Lower Thermosphere, Christopher J. Heale

Doctoral Dissertations and Master's Theses

A 2-D nonlinear, compressible numerical model [Snively and Pasko, 2008] is used in conjunction with ray-theory to investigate the long-range propagation, dissipation and interaction of small-scale gravity waves in the Mesosphere and Lower Thermosphere (MLT) region. The research in this thesis is made up of three distinct studies which build upon each other. The first investigates the thermospheric dissipation of three gravity wave packets representing: (1) A quasi-monochromatic packet, (2) A monochromatic, steady state wave, and (3) A spectrally broad packet, as well as an initial condition specified packet. It is found that dissipation due to molecular viscosity and …

Go to article

Book Review: Heart Of Darkness: Unraveling The Mysteries Of The Invisible Universe, T. D. Oswalt Sep 2013

Book Review: Heart Of Darkness: Unraveling The Mysteries Of The Invisible Universe, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Heart of Darkness : Unraveling the Mysteries of the Invisible Universe by Jeremiah P. Ostriker and Simon Mitton Princeton, 2013 299p, 9780691134307 $27.95, 9781400844647 $27.95

Go to article

Field Localization And The Nambu-Jona-Lasinio Mass Generation Mechanism In An Alternative 5-Dimensional Brane Model, Preston Jones, Gerardo Muñoz, Douglas Singleton, Triyanta Jul 2013

Field Localization And The Nambu-Jona-Lasinio Mass Generation Mechanism In An Alternative 5-Dimensional Brane Model, Preston Jones, Gerardo Muñoz, Douglas Singleton, Triyanta

Publications

We consider a five-dimensional brane world model with a single brane which is distinct from the well known Randall-Sundrum model. We discuss the similarities and differences between our brane model and the Randall-Sundrum brane model. In particular we focus on the localization of five-dimensional fields with different spins—spin 0, spin 1 / 2 , and spin 1—to the brane, and a self-consistent mass-generation mechanism. We find that the brane model studied here has different (and in some cases superior) localization properties for fields/particles with different spins to the brane, as compared to the original five-dimensional brane models. In addition this …

Go to article

Application Of Asymptotic Expansions For Maximum Likelihood Estimators' Errors To Gravitational Waves From Inspiraling Binary Systems: The Network Case, Salvatore Vitale, Michele Zanolin Nov 2011

Application Of Asymptotic Expansions For Maximum Likelihood Estimators' Errors To Gravitational Waves From Inspiraling Binary Systems: The Network Case, Salvatore Vitale, Michele Zanolin

Publications

This paper describes the most accurate analytical frequentist assessment to date of the uncertainties in the estimation of physical parameters from gravitational waves generated by nonspinning binary systems and Earth-based networks of laser interferometers. The paper quantifies how the accuracy in estimating the intrinsic parameters mostly depends on the network signal to noise ratio (SNR), but the resolution in the direction of arrival also strongly depends on the network geometry. We compare results for 6 different existing and possible global networks and two different choices of the parameter space. We show how the fraction of the sky where the one …

Go to article

A New Pulsar Instrumentation At The Allen Telescope Array And The Nancay Radio Telescope, G. Desvignes, William C. Barott, I. Cognard, P. Lespagnol, G. Theureau Jan 2011

A New Pulsar Instrumentation At The Allen Telescope Array And The Nancay Radio Telescope, G. Desvignes, William C. Barott, I. Cognard, P. Lespagnol, G. Theureau

Publications

In the prospect of the gravitational wave background detection with high precision pulsar timing, we recently installed a new coherent dedispersion backend at the Allen Telescope Array (ATA) and the Nançay Radio Telescope (NRT).

Go to article

Gravity Couplings In The Standard-Model Extension, Quentin G. Bailey Dec 2010

Gravity Couplings In The Standard-Model Extension, Quentin G. Bailey

Publications

The Standard-Model Extension (SME) is an action-based expansion describing general Lorentz violation for known matter and fields, including gravity. In this talk, I will discuss the Lorentz-violating gravity couplings in the SME. Toy models that match the SME expansion, including vector and two-tensor models, are reviewed. Finally I discuss the status of experiments and observations probing gravity coefficients for Lorentz violation.

Go to article

Application Of Asymptotic Expansions For Maximum Likelihood Estimators Errors To Gravitational Waves From Binary Mergers: The Single Interferometer Case, M. Zanolin, S. Vitale, N. Makris Jun 2010

Application Of Asymptotic Expansions For Maximum Likelihood Estimators Errors To Gravitational Waves From Binary Mergers: The Single Interferometer Case, M. Zanolin, S. Vitale, N. Makris

Publications

In this paper we describe a new methodology to calculate analytically the error for a maximum likelihood estimate (MLE) for physical parameters from gravitational wave signals. All the existing literature focuses on the usage of the Cramer Rao Lower bounds (CRLB) as a mean to approximate the errors for large signal to noise ratios. We show here how the variance and the bias of an MLE estimate can be expressed instead in inverse powers of the signal to noise ratios where the first order in the variance expansion is the CRLB. As an application we compute the second order of …

Go to article

Lorentz Violation And Gravity, Quentin G. Bailey Apr 2010

Lorentz Violation And Gravity, Quentin G. Bailey

Publications

In the last decade, a variety of high-precision experiments have searched for miniscule violations of Lorentz symmetry. These searches are largely motivated by the possibility of uncovering experimental signatures from a fundamental unified theory. Experimental results are reported in the framework called the Standard-Model Extension (SME), which describes general Lorentz violation for each particle species in terms of its coefficients for Lorentz violation. Recently, the role of gravitational experiments in probing the SME has been explored in the literature. In this talk, I will summarize theoretical and experimental aspects of these works. I will also discuss recent lunar laser ranging …

Go to article

The Equivalence Principle, Uniformly Accelerated Reference Frames, And The Uniform Gravitational Field, Gerardo Muñoz, Preston Jones Mar 2010

The Equivalence Principle, Uniformly Accelerated Reference Frames, And The Uniform Gravitational Field, Gerardo Muñoz, Preston Jones

Publications

The relation between uniformly accelerated reference frames in flat spacetime and the uniform gravitational field is examined in a relativistic context. It is shown that contrary to previous statements, equivalence does not break down in this context. No restrictions to Newtonian approximations or small enclosures are necessary.

Go to article

Book Review: Finding The Big Bang, T. D. Oswalt Oct 2009

Book Review: Finding The Big Bang, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Finding the Big Bang edited by P. James E. Peebles, Lyman A. Page Jr., and R. Bruce Partridge Cambridge, 2009 571p, 9780521519823 $80.00

Go to article

Photometric Calibrations For 21st Century Science, Stephen M. Kent, Terry D. Oswalt, Mary Elizabeth Kaiser, Et Al. Mar 2009

Photometric Calibrations For 21st Century Science, Stephen M. Kent, Terry D. Oswalt, Mary Elizabeth Kaiser, Et Al.

Publications

The answers to fundamental science questions in astrophysics, ranging from the history of the expansion of the universe to the sizes of nearby stars, hinge on our ability to make precise measurements of diverse astronomical objects. As our knowledge of the underlying physics of objects improves along with advances in detectors and instrumentation, the limits on our capability to extract science from measurements is set, not by our lack of understanding of the nature of these objects, but rather by the most mundane of all issues: the precision with which we can calibrate observations in physical units. We stress the …

Go to article

Gravitational Wave Burst Source Direction Estimation Using Time And Amplitude Information, J. Markowitz, M. Zanolin, L. Cadonati, E. Katsavounidis Dec 2008

Gravitational Wave Burst Source Direction Estimation Using Time And Amplitude Information, J. Markowitz, M. Zanolin, L. Cadonati, E. Katsavounidis

Publications

In this article we study two problems that arise when using timing and amplitude estimates from a network of interferometers (IFOs) to evaluate the direction of an incident gravitational wave burst (GWB). First, we discuss an angular bias in the least squares timing-based approach that becomes increasingly relevant for moderate to low signal-to-noise ratios. We show how estimates of the arrival time uncertainties in each detector can be used to correct this bias. We also introduce a stand alone parameter estimation algorithm that can improve the arrival time estimation and provide root-sum-squared strain amplitude (h(rss)) values for each site. In …

Go to article

Book Review: The Road To Galaxy Formation 2nd Ed, T. D. Oswalt Apr 2008

Book Review: The Road To Galaxy Formation 2nd Ed, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The road to galaxy formation 2nd ed by William C. Keel. Springer/Praxis, 2007 262p, 9783540725343 $99.00.

Go to article

Book Review: Your Cosmic Context: An Introduction To Modern Cosmology, T. D. Oswalt Jan 2008

Book Review: Your Cosmic Context: An Introduction To Modern Cosmology, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Your Cosmic Context : an Introduction to Modern Cosmology by Todd Duncan and Craig Tyler Pearson Addison-Wesley, 2008 466p, 0132400103 $80.00, 9780132400107 $80.00.

Go to article

Testing Lorentz Symmetry With Gravity, Quentin G. Bailey Aug 2007

Testing Lorentz Symmetry With Gravity, Quentin G. Bailey

Publications

In this talk, results from the gravitational sector of the Standard-Model Extension (SME) are discussed. The weak-field phenomenology of the resulting modified gravitational field equations is explored. The application of the results to a variety of modern gravity experiments, including lunar laser ranging, Gravity Probe B, binary pulsars, and Earth-laboratory tests, shows promising sensitivity to gravitational coefficients for Lorentz violation in the SME.

Go to article

Signals For Lorentz Violation In Post-Newtonian Gravity, Quentin G. Bailey, V. Alan Kostelecký Aug 2006

Signals For Lorentz Violation In Post-Newtonian Gravity, Quentin G. Bailey, V. Alan Kostelecký

Publications

The pure-gravity sector of the minimal standard-model extension is studied in the limit of Riemann spacetime. A method is developed to extract the modified Einstein field equations in the limit of small metric fluctuations about the Minkowski vacuum, while allowing for the dynamics of the 20 independent coefficients for Lorentz violation. The linearized effective equations are solved to obtain the post-Newtonian metric. The corresponding post-Newtonian behavior of a perfect fluid is studied and applied to the gravitating many-body system. Illustrative examples of the methodology are provided using bumblebee models. The implications of the general theoretical results are studied for a …

Go to article

The Clock Paradox In A Static Homogeneous Gravitational Field, Preston Jones, Lucas F. Wanex Feb 2006

The Clock Paradox In A Static Homogeneous Gravitational Field, Preston Jones, Lucas F. Wanex

Publications

The gedanken experiment of the clock paradox is solved exactly using the general relativistic equations for a static homogeneous gravitational field. We demonstrate that the general and special relativistic clock paradox solutions are identical and in particular that they are identical for finite acceleration. Practical expressions are obtained for proper time and coordinate time by using the destination distance as the key observable parameter. This solution provides a formal demonstration of the identity between the special and general relativistic clock paradox with finite acceleration and where proper time is assumed to be the same in both formalisms. By solving the …

Go to article

Galactic Open Clusters, Ted Von Hippel Sep 2005

Galactic Open Clusters, Ted Von Hippel

Publications

The study of open clusters has a classic feel to it since the subject predates anyone alive today. Despite the age of this topic, I show via an ADS search that its relevance and importance in astronomy has grown faster in the last few decades than astronomy in general. This is surely due to both technical reasons and the interconnection of the field of stellar evolution to many branches of astronomy. In this review, I outline what we know today about open clusters and what they have taught us about a range of topics from stellar evolution to Galactic structure …

Go to article

Book Review: The Edge Of Infinity: Supermassive Black Holes In The Universe, T. D. Oswalt Jun 2004

Book Review: The Edge Of Infinity: Supermassive Black Holes In The Universe, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The Edge of Infinity : Supermassive Black Holes in the Universe by Fulvio Melia. Cambridge, 2003 148p, 0-521-81405-7 $30.00.

Go to article

Book Review: The Big Bang: A View From The 21st Century, T. D. Oswalt Feb 2004

Book Review: The Big Bang: A View From The 21st Century, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of The Big Bang : a View from the 21st Century by David M. Harland. Springer/Praxis, 2003 262p, 1-85233-713-3 $39.95.

Go to article

First Prev Next Last