Search Publications
Space test of the equivalence principle: first results of the MICROSCOPE mission
Bergé, Joel; Chhun, Ratana; Métris, Gilles +31 more
The weak equivalence principle (WEP), stating that two bodies of different compositions and/or mass fall at the same rate in a gravitational field (universality of free fall), is at the very foundation of general relativity. The MICROSCOPE mission aims to test its validity to a precision of 10-15, two orders of magnitude better than cur…
Light propagation in 2PN approximation in the field of one moving monopole II. Boundary value problem
Zschocke, Sven
In this investigation the boundary value problem of light propagation in the gravitational field of one arbitrarily moving body with monopole structure is considered in the second post-Newtonian approximation. The solution of the boundary value problem comprises a set of altogether three transformations: , , and . Analytical solutions of these tra…
Gaia-like astrometry and gravitational waves
Klioner, Sergei A.
This paper discusses the effects of gravitational waves on high-accuracy astrometric observations such as those delivered by Gaia. Depending on the frequency of gravitational waves, two regimes for the influence of gravitational waves on astrometric data are identified: the regime when the effects of gravitational waves directly influence the deri…
Light propagation in 2PN approximation in the field of one moving monopole I. Initial value problem
Zschocke, Sven
In this investigation the light propagation in the gravitational field of one arbitrarily moving body with monopole structure is considered in the second post-Newtonian approximation. It is found that the light trajectory depends on the acceleration of the body. Some of these acceleration terms are important in order to get well-defined logarithmi…
Measuring fN force variations in the presence of constant nN forces: a torsion pendulum ground test of the LISA Pathfinder free-fall mode
Russano, G.; Cavalleri, A.; Cesarini, A. +11 more
LISA Pathfinder is a differential accelerometer with the main goal being to demonstrate the near perfect free-fall of reference test masses, as is needed for an orbiting gravitational wave observatory, with a target sensitivity of 30 fm s-2 Hz-1/2 at 1 mHz. Any lasting background differential acceleration between the two test…
Model-independent analyses of non-Gaussianity in Planck CMB maps using Minkowski functionals
Buchert, Thomas; France, Martin J.; Steiner, Frank
Despite the wealth of Planck results, there are difficulties in disentangling the primordial non-Gaussianity of the Cosmic Microwave Background (CMB) from the secondary and the foreground non-Gaussianity (NG). For each of these forms of NG the lack of complete data introduces model-dependences. Aiming at detecting the NGs of the CMB temperature an…
Constraints on LISA Pathfinder’s self-gravity: design requirements, estimates and testing procedures
Mendes, L.; Madden, S.; Russano, G. +96 more
LISA Pathfinder satellite was launched on 3 December 2015 toward the Sun-Earth first Lagrangian point (L1) where the LISA Technology Package (LTP), which is the main science payload, will be tested. LTP achieves measurements of differential acceleration of free-falling test masses (TMs) with sensitivity below 3× {10}-14 {{m}} {{{s}}}
On the running of the spectral index to all orders: a new model-dependent approach to constrain inflationary models
Zarei, Moslem
In conventional model-independent approaches, the power spectrum of primordial perturbations is characterized by such free parameters as the spectral index, its running, the running of running, and the tensor-to-scalar ratio. In this work we show that, at least for simple inflationary potentials, one can find the primordial scalar and tensor power…
Composite Inflation in the light of 2015 Planck data
Channuie, Phongpichit
In this work, we examine cosmological constraints on models of composite inflation based on the slow-roll approximation by using the recent Planck measurement. We compare the spectral index of curvature perturbation (and its running) and the tensor-to-scalar ratio predicted by such models with Planck 2015 data. We find that the predictions of tech…
The ray tracing analytical solution within the RAMOD framework. The case of a Gaia-like observer
Lattanzi, M. G.; Crosta, M.; Vecchiato, A. +1 more
This paper presents the analytical solution of the inverse ray tracing problem for photons emitted by a star and collected by an observer located in the gravitational field of the Solar System. This solution has been conceived to suit the accuracy achievable by the ESA Gaia satellite (launched on 19 December 2013) consistently with the measurement…