Related papers: Extragalactic Proper Motions: Gravitational Waves …
Gravitational waves sourced by amplified scalar perturbations are a common prediction across a wide range of cosmological models. These scalar curvature fluctuations are inherently nonlinear and typically non-Gaussian. We argue that the…
Since the very beginning of astronomy the location of objects on the sky has been a fundamental observational quantity that has been taken for granted. While precise two dimensional positional information is easy to obtain for observations…
The conjecture is considered that every body induces the wave field which imposes oscillations on the gravitational potential of a body. The function for oscillations is chosen to prevent the gravitational collapse of the matter at the…
Gravitational theories differing from General Relativity may explain the accelerated expansion of the Universe without a cosmological constant. However, to pass local gravitational tests, a "screening mechanism" is needed to suppress, on…
Our understanding of stellar atmospheres and our ability to infer architectures of extrasolar planetary systems rely on understanding the emission of stars at submillimeter to centimeter wavelengths. In this chapter we describe how…
In this paper we consider the Extra-solar Planetary Systems recently discovered in our Galaxy as potential sources of gravitational waves. We estimate the frequency and characteristic amplitude of the radiation they emit due to the orbital…
We compute the effects of a stochastic background of gravitational waves on multiply imaged systems or on weak lensing. There are two possible observable effects, a static relative deflection of images or shear, and an induced time…
We investigate the influence of random variations of the Galactic gravitational field on the apparent celestial positions of extragalactic sources. The basic statistical characteristics of a stochastic process (first-order moments, an…
We obtain the angular distribution of the cosmic rays reaching an observer from an individual source and after propagation through a turbulent magnetic field, for different ratios between the source distance and the diffusion length. We…
The Gaia mission offers a new opportunity to search for the low frequency gravitational wave background using astrometric measurements. In this paper, the astrometric effect of gravitational waves is reviewed, with a particular focus on the…
It was recently proposed that the effects usually attributed to particle dark matter on galaxy scales are due to the displacement of dark energy by baryonic matter, a paradigm known as emergent gravity. This formalism leads to predictions…
We consider thermal effects in the propagation of gravitational waves on a cosmological background. In particular, we consider scalar field cosmologies and study gravitational modes near cosmological singularities. We point out that the…
In the last two decades an anomalous variation in the asymptotic velocity of spacecraft performing a flyby manoeuvre around Earth has been discovered through careful Doppler tracking and orbital analysis. No viable hypothesis for a…
This paper describes some interesting properties of waves in, and oscillations of, the interstellar medium in the direction normal to the plane of the Galaxy. Our purpose is to examine possible reasons for four observed phenomena: the…
Long-wavelength gravitational waves can induce significant temperature anisotropy in the cosmic microwave background. Distinguishing this from anisotropy induced by energy density fluctuations is critical for testing inflationary cosmology…
There is some inconclusive evidence that measurement devices sensitive to local gravitation exhibit anomalous behaviour during solar eclipses. We investigate if these findings can be incorporated into the standard general relativistic model…
We show that the time-dependent Doppler effect should induce measureable deviations of the time history of the projected orbit of a star around the supermassive black hole in the Galactic center (SgrA*) from the expected Keplerian history.…
This work investigates alternative theories of gravity, the solutions to their field equations and the constraints that can be imposed upon them from observation and experiment. Specifically, we consider the cosmologies and spherically…
Gravitational waves can act like gravitational lenses, affecting the observed positions, brightnesses, and redshifts of distant objects. Exact expressions for such effects are derived here in general relativity, allowing for…
We discuss the influence of the cosmological constant $\Lambda$ on the gravitational equations of motion of bodies with arbitrary masses and eventually solve the two-body problem. Observational constraints are derived from measurements of…