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Scientists ditch approximations,begin modeling universe with Einstein’s full theory of General Relativity
Scientists ditch approximations modeling universe Einstein’s full theory General Relativity
2016/7/4
Research teams on both sides of the Atlantic have shown that precise modeling of the universe and its contents will change the detailed understanding of the evolution of the universe and the growth of...
Investigation of symmetries and conserved charges in general relativity
The vector of gravity The black hole mechanics The first law Accelerate the black hole A black hole. Static fixation Bubble time and space
2014/12/9
This thesis presents a series of results relating to conserved charges in general relativity. In particular, we give a general expression for a gravitational charge corresponding to a boost Killing ve...
8th IVS General Meeting
8th IVS General Meeting
2013/10/30
The International VLBI Service for Geodesy and Astrometry (IVS) holds a General Meeting every two years. The purpose of the General Meeting is to assemble representatives from all IVS components to sh...
Inflationary non-Gaussianities in the most general second-order scalar-tensor theories
Inflationary non-Gaussianities in the most general second-order scalar-tensor theories
2011/10/14
For very general scalar-field theories in which the equations of motion are at second-order, we evaluate the three-point correlation function of primordial scalar perturbations generated during inflat...
The Kepler characterization of the variability among A- and F-type stars. I. General overview
Asteroseismology - Stars: oscillations - Stars: variables: δ Scuti - Stars: fundamental parameters - binaries: general - Stars: statistics
2011/9/27
The Kepler spacecraft is providing time series of photometric data with micromagnitude precision for hundreds of A-F type stars. We present a first general characterization of the pulsational behaviou...
Large-scale clustering of galaxies in general relativity
Large-scale clustering galaxies general relativity
2011/10/17
Several recent studies have shown how to properly calculate the observed clustering of galaxies in a relativistic context, and uncovered corrections to the Newtonian calculation that become significan...
A More General Model for the Intrinsic Scatter in Type Ia Supernova Distance Moduli
General Model Intrinsic Scatter Supernova Distance Moduli
2011/10/13
We describe a new formalism to fit the parameters $\alpha$ and $\beta$ that are used in the SALT2 model to determine the standard magnitudes of Type Ia supernovae. The new formalism describes the intr...
On the redundancy of operators and the bispectrum in the most general second-order scalar-tensor theory
redundancy operators bispectrum general second-order scalar-tensor theory
2011/10/19
In this short note we explain how to use the linear equation of motions to simplify the third-order action for the cosmological fluctuations. No field redefinition is needed in this exact procedure wh...
Isotropic extensions of the vacuum solutions in general relativity
Isotropic extensions of the vacuum solutions in general relativity
2011/10/17
In this work we obtain isotropic extensions of the usual spherically symmetric vacuum geometries in general relativity. Exact and perturbative solutions are derived. The classes of geometries obtained...
Astroinformatics of galaxies and quasars: a new general method for photometric redshifts estimation
cosmology: observations galaxies: redshifts methods: data mining surveys
2011/10/10
With the availability of the huge amounts of data produced by current and future large multi-band photometric surveys, photometric redshifts have become a crucial tool for extragalactic astronomy and ...
Enlargement of the Transformation Group of General Relativity: Spherically Symmetric Solutions
Gravity theory, transformation groups Lagrangians fi eld equations stellar model external spherically symmetric solutions
2011/10/18
A theory has been presented previously in which the geometrical structure of a real four-dimensional space time manifold is expressed by a real orthonormal tetrad, and the group of diffeomorphisms is ...
Odyssey 2 : A mission toward Neptune and Triton to test General Relativity
Odyssey mission Neptune Triton General Relativity
2011/10/18
Odyssey 2 will be proposed in December 2010 for the next call of M3 missions for Cosmic Vision 2015-2025. This mission, under a Phase 0 study performed by CNES, will aim at Neptune and Triton. Two set...
General conditions for scale-invariant perturbations in an expanding universe
General conditions scale-invariant perturbations expanding universe
2011/9/29
We investigate the general properties of expanding cosmological models which generate scale-invariant curvature perturbations in the presence of a variable speed of sound. We show that in an expanding...
GRAVITAS : General Relativistic Astrophysics VIa Timing And Spectroscopy: An ESA M3 mission proposal
General Relativistic Astrophysics Spectroscopy mission proposal
2011/9/28
GRAVITAS is an X-ray observatory, designed and optimised to address the ESA Cosmic Vision theme of "Matter under extreme conditions". It was submitted as a response to the call for M3 mission proposal...
General-relativistic model of hot accretion flows with global Compton cooling
accretion, accretion discs – black hole physics – X-rays: binaries – X-rays:general
2011/9/28
We present a model of optically thin, two-temperature, accretion flows using an exact Monte Carlo treatment of global Comptonization, with seed photons from synchrotron and bremsstrahlung emission, as...