A5019510510- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Solar and Space Plasma Dynamics
- Relativity and Gravitational Theory
- Geophysics and Gravity Measurements
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
- Computational Physics and Python Applications
- Gamma-ray bursts and supernovae
- Particle physics theoretical and experimental studies
- French Urban and Social Studies
- Psychoanalysis and Psychopathology Research
- Astrophysics and Star Formation Studies
- Advanced Thermodynamics and Statistical Mechanics
- History and Developments in Astronomy
- Advanced Differential Geometry Research
- Noncommutative and Quantum Gravity Theories
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Atomic and Subatomic Physics Research
- Space Science and Extraterrestrial Life
- Astro and Planetary Science
Centre National de la Recherche Scientifique
2009-2024
Laboratoire Univers et Théories
2008-2024
Université Paris Sciences et Lettres
2020-2024
Université Paris Cité
2008-2023
Janssen (France)
1989-2023
Institut d'Astrophysique de Paris
2015-2020
Sorbonne Université
2014-2020
Observatoire de Paris
1999-2017
Délégation Paris 7
2007-2015
University of Namur
2009-2010
We propose to use alternative cosmic tracers measure the dark energy equation of state and matter content Universe [w(z)&Ωm]. Our proposed method consists two components: (a) tracing Hubble relation using HII galaxies which can be detected up very large redshifts, z∼4, as an supernovae type Ia, (b) measuring clustering pattern X‐ray selected AGN at a median redshift ∼1. Each component in itself provide interesting constraints on cosmological parameters, especially under our anticipation that...
The universality of the halo mass function is investigated in context dark energy cosmologies. This widely used approximation assumes that can be expressed as a matter density omega_m and rms linear fluctuation sigma only, with no explicit dependence on properties or redshift. In order to test this hypothesis we run series 15 high-resolution N-body simulations for different cosmological models. These consists three LCDM cosmologies best fitting WMAP-1, 3 5 years data, toy-models...
view Abstract Citations (173) References (11) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Precollapse Scale Invariance in Gravitational Instability Moutarde, F. ; Alimi, J. -M. Bouchet, R. Pellat, Ramani, A. The transition to the very nonlinear regime during gravitational collapse of collisionless matter an Omega = 1 expanding universe is numerically and analytically investigated. Numerical simulations with different initial conditions are used show that...
In order to quantitatively test the ability of averaged inhomogeneous cosmologies correctly describe observations large-scale properties Universe, we introduce a smoothed template metric corresponding constant spatial curvature model at any time, but with an evolving parameter. This is used compute quantities along approximate effective light cone Universe. As opposed standard Friedmann model, parametrize this by exact scaling cosmology, and also motivate form results on geometrical...
Spatially averaged inhomogeneous cosmologies in classical general relativity can be written the form of effective Friedmann equations with sources that include backreaction terms. In this paper, we propose to describe these terms help a homogeneous scalar field evolving potential; call it 'morphon field'. This new links cosmologies, allowing reinterpret, e.g., quintessence scenarios by routing physical origin source inhomogeneities universe. We investigate one-parameter family scaling...
In the context of ESA M5 (medium mission) call we proposed a new satellite mission, Theia, based on relative astrometry and extreme precision to study motion very faint objects in Universe. Theia is primarily designed local dark matter properties, existence Earth-like exoplanets our nearest star systems physics compact objects. Furthermore, about 15 $\%$ mission time was dedicated an open observatory for wider community propose complementary science cases. With its unique metrology system...
The upcoming generation of galaxy surveys will probe the distribution matter in Universe with unprecedented accuracy. Measurements power spectrum at different scales and red shifts provide stringent constraints on cosmological parameters. However, non-linear this require an accurate evaluation covariance matrix. Here, we compute matrix three-dimensional density for concordance ΛCDM cosmology from ensemble N-body simulations Dark Energy Simulation – Parallel Runs (DEUS-PUR). This consists 12...
Dark energy as a quintessence component causes typical modification of the background cosmic expansion, which in addition to its clustering properties, can leave potentially distinctive signature on large scale structures. Many previous studies have investigated this topic, particularly relation non-linear regime structure formation. However, no careful pre-selection viable models with high precision cosmological data was performed. Here we show that has led misinterpretation (and...
We investigate the non-linear evolution of Baryon Acoustic Oscillations (BAO) in low-redshift matter power spectrum from DEUS-FUR $\Lambda$CDM model simulation. This is first cosmological N-body simulation encompassing full observable cosmic volume, thus allowing variance limited predictions at BAO scales. control effect numerical systematic errors using a series large volume high-resolution simulations. The combined analysis allows us to measure between $z=0$ and $1$ 1% over entire range,...
It is possible to provide a thermodynamic interpretation for the field equations in any diffeomorphism invariant theory of gravity. This insight, turn, leads us possibility deriving gravitational from another variational principle without using metric as dynamical variable. I review this approach and discuss its implications.
We analyze the qualitative behavior of scalar-tensor cosmologies with an arbitrary monotonic \ensuremath{\omega}(\ensuremath{\Phi}) function. In particular, we are interested in theories distinguishable at early epochs from general relativity (GR) but leading to predictions compatible solar-system experiments. After extending method developed by Lorentz-Petzold and Barrow, establish conditions required for convergence towards GR t\ensuremath{\rightarrow}\ensuremath{\infty}. Then, obtain all...
We discuss various types of exotic (non-standard) singularities in the Universe: a Big-Rip (BR or type I), Sudden Future Singularity (SFS II), Generalized Singularity, Finite Scale Factor singularity (FSF III), Big-Separation (BS IV) and $w$-singularity. They are characterized by violation all some energy conditions which results blow-up physical quantities: scale factor, density, pressure, barotropic index. relate emergence these with theories (superstring, brane, higher-order gravity, loop...
We study the imprint of dark energy on density profile matter haloes using a set high-resolution large volume cosmological N-body simulations from Dark Energy Universe Simulation Series. first focus analysis goodness fit Navarro–Frenk–White (NFW) which we find to vary with halo mass and redshift. also that fraction ill-fitted by NFW varies cosmology, thus indicating assembly perturbed profiles carries characteristic signature energy. To access this information independently any parametric...
In this "Invisible Universe" proceedings, we introduce the Dark Energy Universe Simulation Series (DEUSS) which aim at investigating imprints of realistic dark energy models on cosmic structure formation. It represents largest dynamical simulation suite to date in term spatial dynamics. We first present 3 (calibrated latest SNIa and CMB data): LambdaCDM, quintessence with Ratra-Peebles potential, Sugra potential. then isolate various contributions for non-linear matter power spectra from a...
We have performed the first-ever numerical N- body simulation of full observable universe (DEUS "Dark Energy Universe Simulation" FUR "Full Run"). This has evolved 550 billion particles on an Adaptive Mesh Refinement grid with more than two trillion computing points along entire evolutionary history and across 6 order magnitudes length scales, from size Milky Way to that whole universe. To date, this is largest most advanced cosmological ever run. It provides unique information formation...
Observations of colliding galaxy clusters with high relative velocity probe the tail halo pairwise distribution potential providing a powerful test cosmology. As an example it has been argued that discovery Bullet Cluster challenges standard $\Lambda$CDM model predictions. Halo catalogs from N-body simulations have used to estimate probability Bullet-like clusters. However, due simulation volume effects previous studies had rely on Gaussian extrapolation velocities. Here, we perform detail...
I describe the MOND paradigm, which posits a departure from standard physics below certain acceleration scale. This as deduced dynamics in galaxies is found mysteriously to agree with cosmic scales defined by present day expansion rate and density of `dark energy'. put special emphasis on phenomenology critical comparison competing paradigm based classical plus cold dark matter. also briefly nonrelativistic relativistic theories.
We present a detailed calculation of the light element production in framework scalar-tensor theories gravitation. The coupling function \ensuremath{\omega} is described by an appropriate form which reproduces all possible asymptotic behaviors at early times viable cosmological models with monotonic \ensuremath{\omega}(\ensuremath{\Phi}). This gives exact representation for most particular proposed literature, but also first-order approximation to many other theories. In theories, comparison...
We investigate the possibility that dark energy does not couple to gravitation in same way as ordinary matter, yielding a violation of weak and strong equivalence principles on cosmological scales. build transient mechanism which is pushed away from general relativity by Born-Infeld gauge interaction acting an abnormally weighting (dark) energy. This accounts for Hubble diagram far-away supernovae cosmic acceleration time variation gravitational constant while accounting naturally present...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation S. V. Ketov; F(R) SUPERGRAVITY. AIP Conference Proceedings 23 June 2010; 1241 (1): 613–619. https://doi.org/10.1063/1.3462693 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown Menu input auto suggest filter your All ContentAIP...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Daniel G. Figueroa; Preheating the Universe from Standard Model Higgs. AIP Conference Proceedings 23 June 2010; 1241 (1): 578–587. https://doi.org/10.1063/1.3462688 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown Menu input...
The non-Abelian Einstein-Born-Infeld-dilaton theory, which rules the dynamics of tensor-scalar gravitation coupled to a $su(2)$-valued gauge field ruled by Born-Infeld Lagrangian, is studied in cosmological framework. microscopic energy exchange between and dilaton results from nonuniversality coupling gravity modifies usual behavior theories matter fluids. General evolutions are derived for different couplings comparison universal highlighted. Evidences cosmic acceleration presented when...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation P. J. E. Peebles; Phenomenology of the Invisible Universe. AIP Conf. Proc. 23 June 2010; 1241 (1): 175–182. https://doi.org/10.1063/1.3462631 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Dropdown Menu input auto suggest filter...
Taking into account the experimental results of HiRes and AUGER collaborations, present status bounds on Lorentz symmetry violation (LSV) patterns is discussed. Although significant constraints will emerge, a wide range models values parameters still be left open. Cosmological implications allowed LSV are discussed focusing origin our Universe, cosmological constant, dark matter energy. Superbradyons (superluminal preons) may actual constituents vacuum standard particles, form equally sea...