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Showing 1 to 20 of 23 for “"post-Newtonian"”.
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Bridging the gap between post-Newtonian theory and numerical relativity in gravitational-wave data analysis
… from (A) analytical expansions within the post-Newtonian framework and (B) numerical simulations of the full relativistic dynamics. We analyze various strategies to construct complete hybrid waveforms that consist of a post-Newtonian inspiral part matched to numerical-relativity data. We …
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The effect of higher order moments in the post-Newtonian gravitational wave expansion on parameter estimation
… of including higher order amplitude terms in the post-Newtonian expansion for gravitational waves on parameter estimation of inspiraling binary systems. First, we review the mechanism behind gravitational wave production and the formalism behind our estimation of parameters given a specific …
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Gravitational Waves and Inspiraling Compact Binaries in Alternative Theories of Gravity
… reviewing the methods of the Parametrized Post-Newtonian: PPN) framework, Direct Integration of Relaxed Einstein Equations: DIRE), and Matched Filtering.</p><p>In Part III, we calculate the explicit equations of motion for non-spinning compact objects: neutron stars or black holes) to 2.5 …
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Computation Methods for Parametric Analysis of Gravitational Wave Data
… approximation of General Relativity called the Post Newtonian theory. This approximation method is based on the assumption that there is a weak gravity field both inside and around the body. However, scientists cannot justify why Post-Newtonian theory (meant for weak fields) works so well with …
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Modeling the Dynamics of Black Hole Systems and the Ringdown of Black Hole Spacetimes
… including black hole perturbation theory and post-Newtonian theory. First, we describe work to predict and characterize the ringdown gravitational waves from misaligned binary black hole mergers. Working in the large mass ratio limit, we use Teukolsky's equation to calculate the worldline for …
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Gravitational Waves From Perturbed Kerr Black Holes: Two Investigations
… effect of black hole spin on the accuracy of the post-Newtonian approximation. We focus on the gravitational energy produced by the quasicircular, equatorial, extreme mass-ratio inspiral of a compact object into a Kerr black hole of mass M and spin J. For a given dimensionless spin a ≡ J/M2 (in …
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Gravity wave signals from relativistic calculations of binary neutron star coalescence
… testing, and implementation of a Lagrangian, post-Newtonian, smoothed particle hydrodynamics code used to study the gravitational wave signature produced by coalescing neutron star binary systems. Additionally, we have studied the properties of remnants which may be formed during the merger …
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New results from the gravitational lensing of galaxies
… using HST and SDSS to place constraints on the post-Newtonian parameter 7 and the cosmological parameter A. We find y = 1.00 ± 0.04 on kiloparsec scales, consistent with the predictions of general relativity. Assuming a flat universe, we constrain QA = 0.72 ± 0.15, in agreement with results from …
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THE EFFECT OF COMPACT OBJECT SPIN ON THE SEARCH FOR GRAVITATIONAL WAVES FROM BINARY NEUTRON STAR AND NEUTRON STAR-BLACK HOLE MERGERS
… </p> <p>We determine the accuracy of post-Newtonian approximations as gravitational-wave</p> <p>templates in matched-filter based searches for NSBH mergers.</p> <p>We test a geometric method to generate template banks for BNS and NSBH mergers where</p> <p>the components have intrinsic …
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Neutron Star Models in Alternative Theories of Gravity
… scalar field at infinity. These quantities enter post-Newtonian equations of motion and gravitational waveforms of two body systems that are used for gravitational-wave parameter estimation, in order to test these theories against observations.</p><p>The construction of numerical models of neutron …
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Tests of Gravity Theories with Pulsar Timing
… Finally we compare our results with previous Post-Newtonian approximations. We also discuss the stability and the precision of our approach.
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Mathematical Studies on the Asymptotic Behaviour of Gravitational Radiation in General Relativity
… by making certain heuristic connections to the Newtonian theory (Post-Newtonian theory). It is then proved that there exists a unique solution that attains these data in the limit, and the asymptotic properties of this solution are analysed. In this way, it is found that the constructed …
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Modeling Compact Objects with Effective Field Theory
… the literature and obtained the leading order post-Newtonian expansion of our effective description of compact objects to show its predictability. We have expanded on the theoretical foundations of the effective theory for spinning extended objects by showing that the developed theory can be …
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Topics in the Detection of Gravitational Waves from Compact Binary Inspirals
… technique that calibrates existing analytical (Post-Newtonian) waveforms, which are relatively inexpensive, to more accurate fiducial waveforms that are computationally expensive to generate. The resulting waveform family is significantly more accurate than the analytical waveforms, without …
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Probes of strong-field gravity
… of a comparable mass-ratio inspiral using post-Newtonian techniques. The main result is the appearance of dipolar scalar radiation in this class of theories. The dipolar radiation has a frequency dependence which does not arise in GR and is a distinct signature of corrections. Such …
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PROBING THE NATURE OF COMPACT OBJECTS: SCATTERING, TIDES AND QUASINORMAL MODES
… Relativity (GR). Scattering of two BHs in the post-Minkowskian (PM) regime has proven valuable for extracting binary dynamics from gauge-invariant scattering observables. As a simpler analog, we study electromagnetic (EM) scattering of two charged particles in the post-Lorentzian (PL) …
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Analytic Modelling of Gravitational-Wave Source in General Relativity and Alternative Theories of Gravity
… template banks used by LIGO are based on the post-Newtonian (PN) formalism for inspiral and on numerical relativity (NR) for merger and ringdown, or resummation methods such as the effective-one-body (EOB) formalism to describe the complete dynamics. In this thesis, we discuss the construction …
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Υπολογιστική σχετικιστική μελέτη των αστέρων νετρονίων με γενίκευση της μεθόδου των μετανευτωνείων προσεγγίσεων
… την μέθοδο των «μετανευτωνείων προσεγγίσεων» (post-Newtonian approximation, PNA), η οποία είναι ένα διαταρακτικό προσεγγιστικό σχήμα για την επίλυση των εξισώσεων του Εinsteιn. Με το μετανευτώνειο ανάπτυγμα στα πλαίσια της ΓΘΣ βρίσκουμε μία προσεγγιστική λύση των εξισώσεων του Einstein για τον …
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Galaxy-Scale Signatures of Screened Modified Gravities
… stringent constraints from high-precision post-Newtonian tests of gravity, 'screening mechanisms' are invoked, in which the fifth force is suppressed in regions of high density or deep gravitational potential. One example of a screening mechanism is the 'chameleon' mechanism, in which the …
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Topics in Gravitational-Wave Astrophysics
<p>In this dissertation we study the applicability of different waveform models in</p> <p>gravitational wave searches for comparable mass binary black holes. We determine</p> <p>the domain of applicability of the computationally inexpensive closed form models,</p> <p>and the same for the …
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