A5029557191- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Black Holes and Theoretical Physics
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Statistical and numerical algorithms
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Relativity and Gravitational Theory
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Scientific Research and Discoveries
- Astrophysics and Star Formation Studies
- Climate variability and models
- Plant Water Relations and Carbon Dynamics
- Grey System Theory Applications
- Seismology and Earthquake Studies
- Remote-Sensing Image Classification
- Monetary Policy and Economic Impact
- Seismic Waves and Analysis
- Indoor and Outdoor Localization Technologies
- Advanced Differential Geometry Research
- Astrophysical Phenomena and Observations
Excellence Cluster Origins
2021-2023
Ludwig-Maximilians-Universität München
2021-2023
Max Planck Institute for Astrophysics
2015-2021
Durham University
2012-2016
Max Planck Society
2015-2016
Universidade do Porto
2011-2012
Georgia Institute of Technology
2012
We present high signal-to-noise galaxy–galaxy lensing measurements of the Baryon Oscillation Spectroscopic Survey constant mass (CMASS) sample using 250 deg2 weak-lensing data from Canada–France–Hawaii Telescope Lensing and Stripe 82 Survey. compare this signal with predictions mock catalogues trained to match observables including stellar function projected two-dimensional clustering CMASS. show that CMASS, together standard models galaxy–halo connection, robustly predicts a is 20–40 per...
Cosmological models with Galileon gravity are an alternative to the standard ΛCDM paradigm testable predictions at level of its self-accelerating solutions for expansion history, as well large-scale structure formation. Here, we place constraints on full parameter space these using data from cosmic microwave background (CMB) (including lensing), baryonic acoustic oscillations (BAO) and Integrated Sachs-Wolfe (ISW) effect. We pay special attention ISW effect which use cross-spectra, CℓTg, CMB...
We model the linear and nonlinear growth of large scale structure in Cubic Galileon gravity model, by running a suite N-body cosmological simulations using {\tt ECOSMOG} code. Our include Vainshtein screening effect, which reconciles with local tests gravity. In regime, amplitude matter power spectrum increases $\sim 25%$ respect to standard $\Lambda$CDM today. The modified expansion rate accounts for 20%$ this enhancement, while fifth force is responsible only 5%$. This because effective...
Self-consistent N-body simulations of modified gravity models are a key ingredient to obtain rigorous constraints on deviations from general relativity using large-scale structure observations. This paper provides the first detailed comparison results different codes for f (R), Dvali–Gabadadze–Porrati and Symmetron models, starting same initial conditions. We find that fractional deviation matter power spectrum Λ cold dark agrees better than 1 per cent up k ∼ 5–10 h Mpc−1 between codes....
ABSTRACT We present a general method to compute the non-linear matter power spectrum for dark energy (DE) and modified gravity scenarios with per cent-level accuracy. By adopting halo model perturbation theory, we predict reaction of lambda cold (ΛCDM) physics an extended cosmological parameter space. comparing our predictions N-body simulations demonstrate that no-free parameters can recover wide range different w0–wa DE models better than 1 cent accuracy out k ≈ $h \,{\rm Mpc}^{-1}$....
We study lensing by voids in Cubic Galileon and Nonlocal gravity cosmologies, which are examples of theories that modify the potential. find dark matter halo density fields N-body simulations compute their signal analytically from void profiles, we show well fit a simple analytical formula. In model, modifications to inside not screened they approximately double size effects compared GR. The difference is largely determined direct fifth force on less so modified profiles. For this also...
Modern instruments and observational programs in astrophysics cosmology have opened new perspectives for probing general relativity on previously unexplored scales. This review provides both a methodological an survey of the constraints modified-gravity models using astrophysical objects cosmological, weak-field regime. It is embedded framework novel probes project, forum connecting observers theorists involved study tests dark sector interactions.
Abstract The scale-dependent bias effect on the galaxy power spectrum is a very promising probe of local primordial non-Gaussianity (PNG) parameter f NL , but amplitude proportional to b ϕ where linear PNG parameter. Our knowledge currently limited, yet nearly all existing constraints and forecasts assume precise for it. Here, we use BOSS DR12 illustrate how our uncertain prevents us from constraining with given statistical precision σ . Assuming different fixed choices relation between...
Abstract We use hydrodynamical separate universe simulations with the IllustrisTNG model to predict local primordial non-Gaussianity (PNG) bias parameters b ϕ and ϕδ , which enter at leading order in galaxy power spectrum bispectrum. This is first time that measured from either gravity-only or formation simulations. For dark matter halos, popular assumption of universality overpredicts ( 1 ) relation range ≲ 3 by up Δ ∼ linear density bias). The adequacy worse for simulated galaxies,...
Abstract We use N-body simulations to study halo assembly bias (i.e., the dependence of clustering on properties beyond total mass) in density and primordial non-Gaussianity (PNG) linear parameters b 1 ϕ , respectively. consider concentration, spin sphericity as secondary properties, for which we find a clear detection . At fixed mass, impact similar manner, roughly preserving shape ( ) relation satisfied by global population. Halo however, drives opposite directions. This induces...
We study the cosmology of Galileon modified gravity models in linear perturbation regime. derive fully covariant and gauge invariant perturbed field equations using two different methods, which give consistent results, solve them a version {\tt CAMB} code. find that, addition to modifying background expansion history therefore shifting positions acoustic peaks cosmic microwave (CMB) power spectrum, can cluster strongly from early times, causes Weyl gravitational potential grow, rather than...
We study spherical collapse in the Quartic and Quintic Covariant Galileon gravity models within framework of excursion set formalism. derive nonlinear spherically symmetric equations quasi-static weak-field limits, focusing on model parameters that fit current CMB, SNIa BAO data. demonstrate do not admit physical solutions fifth force high density regions, which prevents structure formation this model. For model, we show effective gravitational strength deviates from standard value at late...
We use the latest CMB data from Planck, together with BAO measurements, to constrain full parameter space of Galileon gravity. separately three main branches theory known as Cubic, Quartic and Quintic models, find that all yield a very good fit these data. Unlike in ΛCDM, model constraints are compatible local determinations Hubble predict nonzero neutrino masses at over 5σ significance. also identify low l part lensing spectrum may be able distinguish between ΛCDM models. In Cubic model,...
The velocity field of dark matter and galaxies reflects the continued action gravity throughout cosmic history. We show that low-order moments pairwise distribution ${v}_{12}$ are a powerful diagnostic laws on cosmological scales. In particular, projected line-of-sight galaxy dispersion ${\ensuremath{\sigma}}_{12}(r)$ is very sensitive to presence modified gravity. Using set high-resolution $N$-body simulations, we compute its for class theories: chameleon $f(R)$ Galileon (cubic quartic)....
We present the first constraints on full parameter space of Galileon modified gravity model, considering both cosmological parameters and coefficients which specify additional terms in Lagrangian due to field, we call parameters. use latest cosmic microwave background measurements, along with distance measurements from supernovae baryonic acoustic oscillations, performing a Monte Carlo Markov Chain exploration nine-dimensional space. The integrated Sachs-Wolfe signal can be very different...
We study the nonlinear growth of structure in nonlocal gravity models with aid N-body simulation and spherical collapse halo models. focus on a model which inverse-squared d'Alembertian operator acts Ricci scalar action. For fixed cosmological parameters, this differs from ΛCDM by having lower late-time expansion rate an enhanced time-dependent gravitational strength ∼ 6% larger today). Compared to today, model, massive haloes are slightly more abundant (by 10% at M 1014 M⊙/h) concentrated ≈...
We investigate the performance of semi-analytical modelling large-scale structure in Galileon gravity cosmologies using results from N-body simulations. focus on Cubic and Quartic models that provide a reasonable fit to CMB, SNIa BAO data. demonstrate Sheth-Tormen mass function linear halo bias can be calibrated very good our simulation results. also find concentration-mass relation is well fitted by power law. The nonlinear matter spectrum computed model approach found inaccurate mildly...
We study the impact that uncertainties on assumed relations between galaxy bias parameters have constraints of local PNG fNL parameter. focus relation linear density b1 and bϕ in an idealized forecast setup with multitracer power spectrum bispectrum data. consider two parametrizations bias: 1) one inspired by universality where = 2δc(b1 − p) p is a free parameter; 2) another which product fNL, like bϕ, directly fitted for. The fNL−p plane are markedly bimodal, both central value width...
We perform a validation of estimates the growth rate structure, described by parameter combination $f{\ensuremath{\sigma}}_{8}$, in modified gravity cosmologies. consider an analysis pipeline based on redshift-space distortion modeling clustering wedges statistic galaxy correlation function and apply it to mock catalogues Lambda cold dark matter ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$) normal branch Dvali-Gabadadze-Porrati (DGP) employ halo occupation distribution approach construct our...
We derive the complete super-sample covariance (SSC) of matter and weak lensing convergence power spectra using spectrum response formalism to accurately describe coupling super- sub-survey modes. The SSC term is completely characterized by survey window function, nonlinear full first-order which describes super-survey density tidal field perturbations. Generalized separate universe simulations can efficiently measure these responses in regime structure formation, necessary for applications....
We study the impact that large-scale perturbations of (i) matter density and (ii) primordial gravitational potential with local non-Gaussianity (PNG) have on galaxy formation using IllustrisTNG model. focus linear bias $b_1$ coefficient $b_\phi$ scale-dependent induced by PNG, which describe response number counts to these two types perturbations, respectively. perform our separate universe simulations, in effect is mimicked changes cosmological parameters: modified cosmic for amplitude...
We use field-level forward models of galaxy clustering and the EFT likelihood formalism to study, for first time self-consistently simulated galaxies, relations between linear $b_1$ second-order bias parameters $b_2$ $b_{K^2}$. The utilize all information available in distribution up a given order perturbation theory, which allows us infer these with high signal-to-noise, even from relatively small volumes ($L_{\rm box} = 205{\rm Mpc}/h$). consider galaxies IllustrisTNG simulations, our main...
Abstract We discuss the potential of multi-tracer technique to improve observational constraints local primordial non-Gaussianity (PNG) parameter f nl from galaxy power spectrum. For two samples A and B , constraining is ∝ | b 1 ϕ - |, where are linear PNG bias parameters. show this allows for significantly improved compared traditional expectation based on naive universality-like relations . Using IllustrisTNG simulation data, we find that different equal number splits full sample lead thus...
We compare Einstein-Boltzmann solvers that include modifications to general relativity and find that, for a wide range of models parameters, they agree high level precision. look at three purpose codes primarily model scalar-tensor theories, Jordan-Brans-Dicke (JBD) gravity, code $f(R)$ covariant Galileons, Ho\ifmmode \check{r}\else \v{r}\fi{}ava-Lifschitz two nonlocal gravity. Comparing predictions the angular power spectrum cosmic microwave background dark matter suite different models, we...
We develop a numerical algorithm to solve the high-order nonlinear derivative-coupling equation associated with quartic Galileon model, and implement it in modified version of ramses N-body code study effect field on large-scale matter clustering. The is tested for several configurations different symmetries, works very well. This enables us perform first simulations model which provides good fit cosmic microwave background (CMB) anisotropy, supernovae baryonic acoustic oscillations (BAO)...