54 research outputs found
Scalar-tensor propagation of light in the inner solar system at the millimetric level
In a recent paper [1], motivated by forthcoming space experiments involving
propagation of light in the Solar System, we have proposed an extention of the
IAU metric equations at the c-4 level in General Relativity. However,
scalar-tensor theories may induce corrections numerically comparable to the c-4
general relativistic terms. Accordingly, one first proposes in this paper an
extension of [1] to the scalar-tensor case. The case of a hierarchized system
(such as the Solar system) is emphasized. In this case, the relevant metric
solution is proposed. Then, the geodesic solution relevant for propagation of
light in the inner solar system at the millimetric level is given in explicit
form.Comment: 18 pages, This article can be regarded as an extension of "eprint
arXiv:1003.1889
Relativistic analysis of an earth-satellite time transfer
Analytical treatment of time transfer problem for Earth-Satellite system is
presented. The development was made in a complete relativistic framework. In
accordance with modern clock precision and for low altitude orbits, we neglect
the other bodies and consider only the 1/c^2 Earth potential developed up to
the J_2 term in spherical harmonics.Comment: 4 pages, conferenc
Scalar-Tensor gravity with system-dependent potential and its relation with Renormalization Group extended General Relativity
We show that Renormalization Group extensions of the Einstein-Hilbert action
for large scale physics are not, in general, a particular case of standard
Scalar-Tensor (ST) gravity. We present a new class of ST actions, in which the
potential is not necessarily fixed at the action level, and show that this
extended ST theory formally contains the Renormalization Group case. We also
propose here a Renormalization Group scale setting identification that is
explicitly covariant and valid for arbitrary relativistic fluids.Comment: 29 pages, 2 figs. v2: small changes in text and ref's. v3: further
details on the relation between this work and others on the Renormalization
Group. Version to appear in JCA
Brans-Dicke gravity and the capture of stars by black holes: some asymptotic results
In the context of star capture by a black hole, a new noticeable difference
between Brans-Dicke theory and general relativity gravitational radiation is
pointed out. This feature stems from the non-stationarity of the black hole
state, barring Hawking's theorem.Comment: 4 pages. Submitted to Classical and Quantum Gravit
Relativistic analysis of the LISA long range optical links
The joint ESA/NASA LISA mission consists in three spacecraft on heliocentric
orbits, flying in a triangular formation of 5 Mkm each side, linked by infrared
optical beams. The aim of the mission is to detect gravitational waves in a low
frequency band. For properly processing the science data, the propagation
delays between spacecraft must be accurately known. We thus analyse the
propagation of light between spacecraft in order to systematically derive the
relativistic effects due to the static curvature of the Schwarzschild spacetime
in which the spacecraft are orbiting with time-varying light-distances. In
particular, our analysis allows to evaluate rigorously the Sagnac effect, and
the gravitational (Einstein) redshift.Comment: 6 figures; accepted for publication in PR
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