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Full-Text Articles in Physics

Simulating Magnetospheres With Numerical Relativity: The Giraffe Code, Maria Babiuc-Hamilton Aug 2017

Simulating Magnetospheres With Numerical Relativity: The Giraffe Code, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Numerical Relativity is successful in the simulation of black holes and gravitational waves. In recent years, teams have tackled the problem of the interaction of gravitational and electromagnetic waves. We developed a new code for the numerical simulation of neutron and black hole magnetospheres, using the FFE formalism. We tested the performance of the new code named GiRaFFE, in 1D and 3D test suits. We will study magnetospheres, focusing on jets by the Blandford -Znajek mechanism.


A Hyperbolic Solver For Black Hole Initial Data In Numerical Relativity, Maria Babiuc-Hamilton, Jeff Winicour, I. Racz Jul 2017

A Hyperbolic Solver For Black Hole Initial Data In Numerical Relativity, Maria Babiuc-Hamilton, Jeff Winicour, I. Racz

Maria C. Babiuc-Hamilton

Initial data in numerical relativity. The constraints are formulated as elliptic equations, parabolic equations and strongly hyperbolic equations. This presentation is about a different approach to initial data for black holes, the strongly hyperbolic method.


Effects Of Waveform Model Systematics On The Interpretation Of Gw150914, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, F. Acernese, K. Ackley, C. Adams, T. Adams, Marc Favata, Shaon Ghosh Apr 2017

Effects Of Waveform Model Systematics On The Interpretation Of Gw150914, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, F. Acernese, K. Ackley, C. Adams, T. Adams, Marc Favata, Shaon Ghosh

Department of Physics and Astronomy Faculty Scholarship and Creative Works

Parameter estimates of GW150914 were obtained using Bayesian inference, based on three semi-analytic waveform models for binary black hole coalescences. These waveform models differ from each other in their treatment of black hole spins, and all three models make some simplifying assumptions, notably to neglect sub-dominant waveform harmonic modes and orbital eccentricity. Furthermore, while the models are calibrated to agree with waveforms obtained by full numerical solutions of Einstein's equations, any such calibration is accurate only to some non-zero tolerance and is limited by the accuracy of the underlying phenomenology, availability, quality, and parameter-space coverage of numerical simulations. This paper …


Investigating The Instability Of The Torus Around The Blackhole In The Presence Of The Radial And Angular Velocity Perturbations, Orhan Dönmez Jan 2017

Investigating The Instability Of The Torus Around The Blackhole In The Presence Of The Radial And Angular Velocity Perturbations, Orhan Dönmez

Turkish Journal of Physics

We have performed the numerical simulation of the perturbed relativistic torus around the black hole by solving the general relativistic hydrodynamics equations on the equatorial plane. We have monitored the different simple models by applying the radial and angular velocity perturbations to the steady state torus around the black hole. The instabilities are triggered by adding the subsonic velocity fields over the radial and angular velocities of the stable torus. We have found the disk instability so-called the Papaloizou-Pringle instability and excited modes of the Quasi-Periodic Oscillations (QPOs) in the thin disk approximation case. The significant oscillations and oscillation modes …