scholarly journals Neutron star mergers as a probe of modifications of general relativity with finite-range scalar forces

2018 ◽  
Vol 97 (6) ◽  
Author(s):  
Laura Sagunski ◽  
Jun Zhang ◽  
Matthew C. Johnson ◽  
Luis Lehner ◽  
Mairi Sakellariadou ◽  
...  
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Finite Range

Merger of black hole and neutron star in general relativity

2008 ◽  
Author(s):  
Masaru Shibata ◽  
Keisuke Taniguchi ◽  
Koji Uryū ◽  
Ye-Fei Yuan ◽  
Xiang-Dong Li ◽  
...  
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Neutron Star

scholarly journals Radio emission from a pulsar’s magnetic pole revealed by general relativity

Science ◽  
2019 ◽  
Vol 365 (6457) ◽  
pp. 1013-1017 ◽  
Author(s):  
Gregory Desvignes ◽  
Michael Kramer ◽  
Kejia Lee ◽  
Joeri van Leeuwen ◽  
Ingrid Stairs ◽  
...  
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Radio Emission ◽  
Neutron Stars ◽  
Geometrical Model ◽  
Spin Axis ◽  
Magnetic Pole ◽  
Polarization Model ◽  
Binary Pulsars ◽  
Relativistic Treatment

Binary pulsars are affected by general relativity (GR), causing the spin axis of each pulsar to precess. We present polarimetric radio observations of the pulsar PSR J1906+0746 that demonstrate the validity of the geometrical model of pulsar polarization. We reconstruct the (sky-projected) polarization emission map over the pulsar’s magnetic pole and predict the disappearance of the detectable emission by 2028. Two tests of GR are performed using this system, including the spin precession for strongly self-gravitating bodies. We constrain the relativistic treatment of the pulsar polarization model and measure the pulsar beaming fraction, with implications for the population of neutron stars and the expected rate of neutron star mergers.

THE DOUBLE PULSAR SYSTEM J0737–3039

2005 ◽  
Vol 20 (29) ◽  
pp. 7035-7044 ◽  
Author(s):  
D. R. LORIMER
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Gravitational Wave ◽  
Detection Rate ◽  
Order Effects ◽  
Gravitational Wave Detector ◽  
High Detection Rate ◽  
Wave Detector ◽  
High Detection ◽  
Order Of Magnitude

The double pulsar system J0737 – 3039 – a 22.7 ms pulsar in a compact 2.4 hr orbit about a 2.7 s pulsar was one of the long-awaited "holy grails" of pulsar astronomy. After only two years of timing, the system is close to surpassing the original Hulse-Taylor binary as a test of general relativity. On-going timing should soon reveal second-order effects in the post-Newtonian parameters. In addition, the observed interactions of the radio beams of the two pulsars provide a unique laboratory for probing neutron star magnetospheres and relativistic winds. Finally, a revised estimate of the cosmic rate of double neutron star mergers including J0737 – 3039 boosts previous estimates by an order of magnitude and suggests a high detection rate for the advanced LIGO gravitational wave detector.

scholarly journals FINITE-RANGE GRAVITY AND ITS ROLE IN GRAVITATIONAL WAVES, BLACK HOLES AND COSMOLOGY

2003 ◽  
Vol 12 (10) ◽  
pp. 1905-1959 ◽  
Author(s):  
S. V. BABAK ◽  
L. P. GRISHCHUK
Keyword(s):  
General Relativity ◽  
Field Experiments ◽  
Small Mass ◽  
Weak Field ◽  
Static Field ◽  
Accelerated Expansion ◽  
Finite Range ◽  
Theoretical Formulation ◽  
Perfect Agreement ◽  
Mass Terms

Theoretical considerations of fundamental physics, as well as certain cosmological observations, persistently point out to permissibility, and maybe necessity, of macroscopic modifications of the Einstein general relativity. The field theoretical formulation of general relativity helped us to identify the phenomenological seeds of such modifications. They take place in the form of very specific mass terms, which appear in addition to the field theoretical analog of the usual Hilbert–Einstein Lagrangian. We derive and study exact nonlinear equations of the theory, along with its linear approximation. We interpret the added terms as masses of spin-2 and spin-0 gravitons. The arising finite-range gravity is a fully consistent theory, which smoothly approaches general relativity in the massless limit, that is, when both masses tend to zero and the range of gravity tends to infinity. We show that all local weak-field predictions of the theory are in perfect agreement with the available experimental data. However, some other conclusions of the nonlinear massive theory are in a striking contrast with those of general relativity. We show in detail how the arbitrarily small mass terms eliminate the black hole event horizon and replace a permanent power-law expansion of a homogeneous isotropic universe with an oscillatory behaviour. One variant of the theory allows the cosmological scale factor to exhibit an 'accelerated expansion' instead of slowing down to a regular maximum of expansion. We show in detail why the traditional, Fierz–Pauli, massive gravity is in conflict not only with the static-field experiments, but also with the available indirect gravitational-wave observations. At the same time, we demonstrate the incorrectness of the widely held belief that the non-Fierz–Pauli theories possess "negative energies" and "instabilities."

Dynamical evolution of black hole-neutron star binaries in general relativity: Simulations of tidal disruption

2006 ◽  
Vol 73 (2) ◽  
Author(s):  
Joshua A. Faber ◽  
Thomas W. Baumgarte ◽  
Stuart L. Shapiro ◽  
Keisuke Taniguchi ◽  
Frederic A. Rasio
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Neutron Star ◽  
Dynamical Evolution ◽  
Tidal Disruption

General relativity and neutron stars

2016 ◽  
Vol 31 (02n03) ◽  
pp. 1641017
Author(s):  
D. G. Yakovlev
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Mass Measurements ◽  
Einstein Theory ◽  
Superdense Matter ◽  
Compact Binaries ◽  
Star Models ◽  
Neutron Star Mass

General Relativity affects all major aspects of neutron star structure and evolution including radiation from the surface, neutron star models, evolution in compact binaries. It is widely used for neutron star mass measurements and for studying properties of superdense matter in neutron stars. Observations of neutron stars help testing General Relativity and planning gravitational wave experiments. No deviations from Einstein Theory of Gravity have been detected so far from observations of neutron stars.

scholarly journals Binary pulsars and tests of general relativity

2009 ◽  
Vol 5 (S261) ◽  
pp. 218-227 ◽  
Author(s):  
I. H. Stairs
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
White Dwarf ◽  
Strong Field ◽  
Binding Energies ◽  
Tests Of General Relativity ◽  
Binary Pulsars ◽  
The Difference

AbstractBinary pulsars are a valuable laboratory for gravitational experiments. Double-neutron-star systems such as the double pulsar provide the most stringent tests of strong-field gravity available to date, while pulsars with white-dwarf companions constrain departures from general relativity based on the difference in gravitational binding energies in the two stars. Future observations may open up entirely new tests of the predictions of general relativity.

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