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2017

Gravitational waves

Articles 1 - 13 of 13

Full-Text Articles in Physical Sciences and Mathematics

Undergraduate Research In Gravitational Waves Astronomy At Marshall University, Maria Babiuc-Hamilton Dec 2017

Undergraduate Research In Gravitational Waves Astronomy At Marshall University, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

This is a presentation of undergraduate student research into gravitational waves at Marshall University.


Gw151226: Observation Of Gravitational Waves From A 22-Solar-Mass Binary Black Hole Coalescence, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepanczyk, M. Zanolin, Et Al. Nov 2017

Gw151226: Observation Of Gravitational Waves From A 22-Solar-Mass Binary Black Hole Coalescence, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepanczyk, M. Zanolin, Et Al.

Michele Zanolin

We report the observation of a gravitational-wave signal produced by the coalescence of two stellar-mass black holes. The signal, GW151226, was observed by the twin detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) on December 26, 2015 at 03:38:53 UTC. The signal was initially identified within 70 s by an online matched-filter search targeting binary coalescences. Subsequent off-line analyses recovered GW151226 with a network signal-to-noise ratio of 13 and a significance greater than 5 σ. The signal persisted in the LIGO frequency band for approximately 1 s, increasing in frequency and amplitude over about 55 cycles from 35 to 450 …


Search For Transient Gravitational Waves In Coincidence With Short-Duration Radio Transients During 2007-2013, B. P. Abbott, K. Gill, B. Hughey, D. Stiles, M. Szczepańczyk, M. Zanolin, Et Al. Nov 2017

Search For Transient Gravitational Waves In Coincidence With Short-Duration Radio Transients During 2007-2013, B. P. Abbott, K. Gill, B. Hughey, D. Stiles, M. Szczepańczyk, M. Zanolin, Et Al.

Michele Zanolin

We present an archival search for transient gravitational-wave bursts in coincidence with 27 single pulse triggers from Green Bank Telescope pulsar surveys, using the LIGO, Virgo and GEO interferometer network. We also discuss a check for gravitational-wave signals in coincidence with Parkes Fast Radio Bursts using similar methods. Data analyzed in these searches were collected between 2007 and 2013. Possible sources of emission of both short-duration radio signals and transient gravitational-wave emission include starquakes on neutron stars, binary coalescence of neutron stars, and cosmic string cusps. While no evidence for gravitational-wave emission in coincidence with these radio transients was found, …


Observing Gravitational-Wave Transient Gw150914 With Minimal Assumptions, B. P. Abbott, K. Gill, B. Hughey, M. Szczepańczyk, M. Zanolin, Et Al. Nov 2017

Observing Gravitational-Wave Transient Gw150914 With Minimal Assumptions, B. P. Abbott, K. Gill, B. Hughey, M. Szczepańczyk, M. Zanolin, Et Al.

Michele Zanolin

The gravitational-wave signal GW150914 was first identified on September 14, 2015, by searches for short-duration gravitational-wave transients. These searches identify time-correlated transients in multiple detectors with minimal assumptions about the signal morphology, allowing them to be sensitive to gravitational waves emitted by a wide range of sources including binary black hole mergers. Over the observational period from September 12 to October 20, 2015, these transient searches were sensitive to binary black hole mergers similar to GW150914 to an average distance of ∼600  Mpc. In this paper, we describe the analyses that first detected GW150914 as well as the parameter estimation …


Towards A Standardized Characteristic Extraction Tool, Maria Babiuc-Hamilton Aug 2017

Towards A Standardized Characteristic Extraction Tool, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Knowing the precise details of the gravitational wave signature obtained from numerical simulations of binary black hole mergers is a key requirement for meaningful detection and scientific interpretation of the data. However, the waveforms are not easy to be accurately computed. The importance of this problem to the future of gravitational wave astronomy is well recognized. Cauchy-Characteristic Extraction (CCE) is the most precise and refined extraction method available. The CCE technique connects the strong-field Cauchy evolution of the spacetime near the merger to the characteristic evolution to future null infinity where the waveform is extracted in an unambiguous way. Recently, …


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.


Towards A Fully Nonlinear Cauchy Characteristic Extraction, Maria Babiuc-Hamilton Aug 2017

Towards A Fully Nonlinear Cauchy Characteristic Extraction, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

The artificial finite outer boundary present in Cauchy codes introduce two sources of error: The outer boundary condition and waveform extraction at an inner worldtube. The problem of proper boundary condition for a radiating system can be solved only by extension to Ι+ (conformal compactification). Cauchy Characteristic Extraction (CCE) offers a means to avoid these errors.


Towards Improved Accuracy Of Gravitational Waves Extraction, Maria Babiuc-Hamilton Aug 2017

Towards Improved Accuracy Of Gravitational Waves Extraction, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Results in developing two new methods to improve the accuracy of waveform extraction using characteristic evolution. Numerical method: circular boundaries, with angular dissipation in the characteristic code. Geometric method: computation of Weyl tensor component Y4 at null infinity, in a conformally compactified treatment. Comparison and calibration in tests problems based upon linearized waves.


Gravitational & Electromagnetic Waves On The Null Cone, Maria Babiuc-Hamilton Aug 2017

Gravitational & Electromagnetic Waves On The Null Cone, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Bondi (1962) proved mathematically the existence of gravitational waves at null infinity. He found an exact solution of Einstein equations. Within this metric, he calculated the loss of mass due to the emission of gravitational waves. The mas of a system is constant if and only if there is no news. If there is news, the mass decreases as long as there are news.


Steps Towards A Nonlinear Cauchy-Characteristic Code Patching, Maria Babiuc-Hamilton Jul 2017

Steps Towards A Nonlinear Cauchy-Characteristic Code Patching, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Cauchy-characteristic extractions (CCE) avoids the errors due to extraction at finite worldtube. The Cauchy and the characteristic approaches have complementary strengths and weaknesses. Unification of the two methods is a promising way of combining the strengths of both formalisms.


An Analysis Of The Gravitational Waves Null Memory, Maria Babiuc-Hamilton Jul 2017

An Analysis Of The Gravitational Waves Null Memory, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Gravitational wave astronomy sees (hears) gravitational waves by observing the phenomena of gravitational and electromagnetic memory, and the formation of trapped surfaces and horizons.


Tools For Gravitational Wave Astronomy, Maria Babiuc-Hamilton Jul 2017

Tools For Gravitational Wave Astronomy, Maria Babiuc-Hamilton

Maria C. Babiuc-Hamilton

Gravitational waves have been confirmed. Tools are available for their study, including the Einstein Toolkit, SimulationTools and the SXS Gravitational Waveform Database.


A New Algorithm For The Numerical Computation Of Gravitational Waves, Maria Babiuc-Hamilton, Jeff Winicour Jul 2017

A New Algorithm For The Numerical Computation Of Gravitational Waves, Maria Babiuc-Hamilton, Jeff Winicour

Maria C. Babiuc-Hamilton

With gravitational waves, Gravitational Wave Astronomy can “see” colliding back holes and galaxies, the birth of a black hole in a supernova, the growth pains of our universe and the structure of spacetime.