Related papers: Pulsar Constraints on Screened Modified Gravity
The timing of millisecond pulsars has long been used as an exquisitely precise tool for testing the building blocks of general relativity, including the strong equivalence principle and Lorentz symmetry. Observations of binary systems…
We present a unifying treatment for metric and scalar perturbations across different energy regimes in scalar-tensor theories of gravity. To do so, we introduce two connected symmetry-breaking patterns: one due to the acquisition of…
Scalar fields are crucial components in high energy physics and extensions of General Relativity. The fact they are not observed in the solar system may be due to a mechanism which screens their presence in high dense regions. We show how…
Modified gravity theories often contain a scalar field of gravitational strength which interacts with matter. We examine constraints on the range and the coupling strength of a scalar gravitational degree of freedom using a subset of…
Stars are stretched by tidal interactions in tight binaries, and changes to their projected areas introduce photometric variations twice per orbit. Hermes et al. (2014, ApJ, 792, 39) utilized measurements of these ellipsoidal variations to…
We study black holes in shift-symmetric scalar Gauss-Bonnet gravity extended by a cubic Galileon interaction with a distinct energy scale. Introducing this hierarchy profoundly modifies the theory's phenomenology. The cubic interaction…
Observations of the TeV halos associated with nearby pulsars indicate that these objects inject significant fluxes of very high-energy electron-positrons pairs into the interstellar medium (ISM), thereby likely providing the dominant…
In this paper we use Delta P = -1.772341 +/- 13.153788 s between the phenomenologically determined orbital period P_b of the PSR J0737-3039 double pulsar system and the purely Keplerian period P^(0)=2\pi\sqrt{a^3/G(m_A+m_B)} calculated with…
The space-time metric is widely believed to be subject to stochastic fluctuations induced by quantum gravity at the Planck scale. This work is based on two different phenomenological approaches being currently made to this topic, and…
Recently published results \citep{kijak2011b} indicated the evidence for a new aspect in radio pulsars spectra. We studied the radio spectrum of PSR B1259-63 in an unique binary with Be star LS 2883 and showed that this pulsar undergoes a…
We explore scalar radiation from neutron star-black hole binaries in scalar-tensor theories with kinetic screening ($K$-essence). Using 3+1 numerical relativity simulations in the decoupling limit, we investigate scalar dipole and…
Relativistic phenomena (orbital precession, Shapiro delay, and/or orbital decay) have been measured in Arecibo timing observations of four pulsar-white dwarf binaries, leading to constraints on the neutron star masses. We have detected the…
A novel constraint on $f(R)$ theories of gravity is obtained from the gravitational wave signal emitted from the binary neutron star merger event GW170817. The $f(R)$ theories possess an additional massive scalar degree of freedom apart…
The recent observations of neutron star mergers have changed our perspective on scalar- tensor theories of gravity, favouring models where gravitational waves travel at the speed of light. In this work we consider a scalar-tensor set-up…
We extend the chameleon models by considering Scalar-Fluid theories where the coupling between matter and the scalar field can be represented by a quadratic effective potential with density-dependent minimum and mass. In this context, we…
Binary pulsars allow us to carry out precision tests of gravity and have placed stringent bounds on a broad class of theories beyond general relativity. Current and future radio telescopes, such as FAST, SKA, and MeerKAT, may find a new…
We present a statistical study of pulsars and millisecond pulsars (MSPs) based on multiwavelength observations in the Galactic Field and Globular Clusters. We examine their emission properties, timing behavior, and spatial distributions,…
We study linear cosmological perturbations in a previously introduced family of deformations of general relativity characterized by the absence of new degrees of freedom. The homogeneous and isotropic background in this class of theories is…
We investigate the propagation of gravitational waves in the context of fourth order gravity nonminimally coupled to a massive scalar field. Using the damping of the orbital period of coalescing stellar binary systems, we impose constraints…
This talk reviews the constraints imposed by binary-pulsar data on gravity theories, and notably on "scalar-tensor" theories which are the most natural alternatives to general relativity. Because neutron stars have a strong gravitational…