Binary Pulsar Tests of General Relativity in the Presence of Low-Frequency Noise

AbstractThe influence of the low-frequency timing noise on the precision of measurements of the Keplerian and post-Keplerian orbital parameters in binary pulsars is studied. Fundamental limits on the accuracy of tests of alternative theories of gravity in the strong-field regime are established. The gravitational low-frequency timing noise formed by an ensemble of binary stars is briefly discussed.

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Stability of pulsar rotational and orbital periods

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310008938 ◽

2009 ◽

Vol 5 (H15) ◽

pp. 226-227

Author(s):

Sergei Kopeikin

Keyword(s):

General Relativity ◽

Time Scale ◽

Random Noise ◽

Low Frequency ◽

Frequency Noise ◽

Tests Of General Relativity ◽

Orbital Parameters ◽

Pulsar Timing ◽

Orbital Periods ◽

The Stability

AbstractMillisecond and binary pulsars are the most stable astronomical standards of frequency. They can be applied to solving a number of problems in astronomy and time-keeping metrology including the search for a stochastic gravitational wave background in the early universe, testing general relativity, and establishing a new time-scale. The full exploration of pulsar properties requires that proper unbiased estimates of spin and orbital parameters of the pulsar be obtained. These estimates depend essentially on the random noise components present in pulsar timing residuals. The instrumental white noise has predictable statistical properties and makes no harm for interpretation of timing observations, while the astrophysical/geophyeical low-frequency noise corrupts them, thus, reducing the quality of tests of general relativity and decreasing the stability of the pulsar time scale.

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Observational tests of general relativity and alternative theories of gravity with Galactic Center observations using current and future large observational facilities

Contributions of the Astronomical Observatory Skalnaté Pleso ◽

10.31577/caosp.2020.50.1.203 ◽

2020 ◽

Vol 50 (1) ◽

Author(s):

A.F. Zakharov ◽

P. Jovanović ◽

D. Borka ◽

V. Borka Jovanović

Keyword(s):

General Relativity ◽

Galactic Center ◽

Alternative Theories Of Gravity ◽

Tests Of General Relativity ◽

Theories Of Gravity ◽

Alternative Theories

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TESTS OF GENERAL RELATIVITY AND ALTERNATIVE THEORIES OF GRAVITY USING GRAVITATIONAL WAVE OBSERVATIONS

International Journal of Modern Physics D ◽

10.1142/s0218271813410125 ◽

2013 ◽

Vol 22 (01) ◽

pp. 1341012 ◽

Cited By ~ 17

Author(s):

K. G. ARUN ◽

ARCHANA PAI

Keyword(s):

General Relativity ◽

Gravitational Wave ◽

Strong Field ◽

Information Matrix ◽

Simons Theory ◽

Alternative Theories Of Gravity ◽

Newtonian Theory ◽

Theories Of Gravity ◽

Model Independent ◽

Alternative Theories

Gravitational wave (GW) observations of coalescing compact binaries will be unique probes of strong-field, dynamical aspects of relativistic gravity. We present a short review of various schemes proposed in the literature to test general relativity (GR) and alternative theories of gravity using inspiral waveforms. Broadly these schemes may be classified into two types: model dependent and model independent. In the model dependent category, GW observations are compared against a specific waveform model representative of a particular theory or a class of theories such as scalar-tensor theories, dynamical Chern–Simons theory and massive graviton theories. Model independent tests are attempts to write down a parametrized gravitational waveform where the free parameters take different values for different theories and (at least some of) which can be constrained by GW observations. We revisit some of the proposed bounds in the case of downscaled LISA configuration (eLISA) and compare them with the original LISA configuration. We also compare the expected bounds on alternative theories of gravity from ground-based and space-based detectors and find that space-based GW detectors can test GR and other theories of gravity with unprecedented accuracies. We then focus on a recent proposal to use singular value decomposition of the Fisher information matrix to improve the accuracies with which post-Newtonian theory can be tested. We extend those results to the case of space-based detector eLISA and discuss its implications.

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The Polarizations of Gravitational Waves

Universe ◽

10.3390/universe4080085 ◽

2018 ◽

Vol 4 (8) ◽

pp. 85 ◽

Cited By ~ 15

Author(s):

Yungui Gong ◽

Shaoqi Hou

Keyword(s):

General Relativity ◽

Gravitational Wave ◽

Gravitational Waves ◽

High Speed ◽

Strong Field ◽

Alternative Theories Of Gravity ◽

Pulsar Timing ◽

Theories Of Gravity ◽

Alternative Theories

The gravitational wave provides a new method to examine General Relativity and its alternatives in the high speed, strong field regime. Alternative theories of gravity generally predict more polarizations than General Relativity, so it is important to study the polarization contents of theories of gravity to reveal the nature of gravity. In this talk, we analyze the polarization contents of Horndeski theory and f(R) gravity. We find out that in addition to the familiar plus and cross polarizations, a massless Horndeski theory predicts an extra transverse polarization, and there is a mix of pure longitudinal and transverse breathing polarizations in the massive Horndeski theory and f(R) gravity. It is possible to use pulsar timing arrays to detect the extra polarizations in these theories. We also point out that the classification of polarizations using Newman–Penrose variables cannot be applied to massive modes. It cannot be used to classify polarizations in Einstein-æther theory or generalized Tensor-Vector-Scalar (TeVeS) theory, either.

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SCIENTIFIC POTENTIAL OF DECIGO PATHFINDER AND TESTING GR WITH SPACE-BORNE GRAVITATIONAL WAVE INTERFEROMETERS

International Journal of Modern Physics D ◽

10.1142/s0218271813410137 ◽

2013 ◽

Vol 22 (01) ◽

pp. 1341013 ◽

Cited By ~ 34

Author(s):

KENT YAGI

Keyword(s):

Solar System ◽

Gravitational Wave ◽

Strong Field ◽

Alternative Theories Of Gravity ◽

Black Hole Binaries ◽

Future Space ◽

Stringent Constraint ◽

Scientific Potential ◽

Theories Of Gravity ◽

Alternative Theories

Deci-Hertz Interferometer Gravitational Wave Observatory (DECIGO) Pathfinder (DPF) has an ability to detect gravitational waves (GWs) from galactic intermediate mass black hole binaries. If the signal is detected, it would be possible to determine parameters of the binary components. Furthermore, by using future space-borne GW interferometers, it would be possible to test alternative theories of gravity in the strong field regime. In this review paper, we first explain how the detectors like DPF and DECIGO/BBO work and discuss the expected event rates. Then, we review how the observed gravitational waveforms from precessing compact binaries with slightly eccentric orbits can be calculated both in general relativity and in alternative theories of gravity. For the latter, we focus on Brans–Dicke (BD) and massive gravity (MG) theories. After reviewing these theories, we show the results of the parameter estimation with DPF using the Fisher analysis. We also discuss a possible joint search of DPF and ground-based interferometers. Then, we show the results of testing alternative theories of gravity using future space-borne interferometers. DECIGO/BBO would be able to place 4–5 orders of magnitude stronger constraint on BD theory than the solar system experiment. This is still 1–2 orders of magnitude stronger than the future solar system mission such as ASTROD I. On the other hand, LISA should be able to put four orders of magnitude more stringent constraint on the mass of the graviton than the current solar system bound. DPF may be able to place comparable constraint on the MG theories as the solar system bound. We also discuss the prospects of using eLISA and ASTROD-GW in testing alternative theories of gravity. The bounds using eLISA are similar to the LISA ones, but ASTROD-GW performs the best in constraining MG theories among all the GW detectors considered in this paper.

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Slowly rotating topological neutron stars: universal relations and epicyclic frequencies

The European Physical Journal C ◽

10.1140/epjc/s10052-020-08473-y ◽

2020 ◽

Vol 80 (9) ◽

Author(s):

Victor I. Danchev ◽

Daniela D. Doneva ◽

Stoytcho S. Yazadjiev

Keyword(s):

General Relativity ◽

Neutron Stars ◽

Strong Field ◽

Compact Objects ◽

X Ray ◽

Tests Of General Relativity ◽

New Type ◽

Theories Of Gravity ◽

Scalar Theories ◽

The Moment

AbstractIn the modern era of abundant X-ray detections and the increasing momentum of gravitational waves astronomy, tests of general relativity in strong field regime become increasingly feasible and their importance for probing gravity cannot be understated. To this end, we study the characteristics of slowly rotating topological neutron stars in the tensor-multi-scalar theories of gravity following the static study of this new type of compact objects by two of the authors. We explore the moment of inertia and verify that universal relations known from general relativity hold for this new class of compact objects. Furthermore, we study the properties of their innermost stable circular orbits and the epicyclic frequencies due to the latter’s hinted link to observational quantities such as quasi-periodic X-ray spectrum features.

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Scope Out Multiband Gravitational-Wave Observations of GW190521-Like Binary Black Holes with Space Gravitational Wave Antenna B-DECIGO

Universe ◽

10.3390/universe7030053 ◽

2021 ◽

Vol 7 (3) ◽

pp. 53

Author(s):

Hiroyuki Nakano ◽

Ryuichi Fujita ◽

Soichiro Isoyama ◽

Norichika Sago

Keyword(s):

Black Holes ◽

Gravitational Wave ◽

Frequency Band ◽

Strong Field ◽

Signal To Noise Ratio ◽

Low Frequency ◽

Next Generation ◽

Estimation Errors ◽

Tests Of General Relativity ◽

Wave Signal

The gravitational wave event, GW190521, is the most massive binary black hole merger observed by ground-based gravitational wave observatories LIGO/Virgo to date. While the observed gravitational wave signal is mainly in the merger and ringdown phases, the inspiral gravitational wave signal of the GW190521-like binary will be more visible to space-based detectors in the low-frequency band. In addition, the ringdown gravitational wave signal will be louder in the next generation (3G) of ground-based detectors in the high-frequency band, displaying the great potential of multiband gravitational wave observations. In this paper, we explore the scientific potential of multiband observations of GW190521-like binaries with a milli-Hz gravitational wave observatory: LISA; a deci-Hz observatory: B-DECIGO; and (next generation of) hecto-Hz observatories: aLIGO and ET. In the case of quasicircular evolution, the triple-band observations of LISA, B-DECIGO, and ET will provide parameter estimation errors of the masses and spin amplitudes of component black holes at the level of order of 1–10%. This would allow consistency tests of general relativity in the strong field at an unparalleled precision, particularly with the “B-DECIGO + ET” observation. In the case of eccentric evolution, the multiband signal-to-noise ratio found in “B-DECIGO + ET” observation would be larger than 100 for a five-year observation prior to coalescence, even with high final eccentricities.

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