A5055882641- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Dark Matter and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Blind Source Separation Techniques
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Spectroscopy and Laser Applications
- Adaptive optics and wavefront sensing
- Medical Image Segmentation Techniques
- Advanced Thermodynamics and Statistical Mechanics
- Astrophysics and Star Formation Studies
- Quantum Mechanics and Applications
- Optical measurement and interference techniques
- Advanced Image Processing Techniques
- Solar and Space Plasma Dynamics
- Advanced Vision and Imaging
- Astronomical Observations and Instrumentation
- Stochastic processes and financial applications
- Differential Equations and Numerical Methods
- Historical Astronomy and Related Studies
- Relativity and Gravitational Theory
University of Bonn
2021-2023
Durham University
2019-2023
University of Sussex
2015-2019
University of Göttingen
2012-2015
We present a joint likelihood analysis of the real-space power spectrum and bispectrum measured from variety halo galaxy mock catalogs. A novel aspect this work is inclusion nonlinear triangle configurations for bispectrum, made possible by complete next-to-leading order ("one-loop") description bias, as already common practice spectrum. Based on goodness-of-fit unbiasedness parameter posteriors, we accomplish stringent validation model compared to leading ("tree-level") bispectrum. Using...
We present the analysis of full shape anisotropic clustering measurement from extended Baryon Oscillation Spectroscopic Survey (eBOSS) quasar sample together with combined galaxy (BOSS), re-analysed using an updated recipe for non-linear matter power spectrum and non-local bias parameters. obtain constraints flat $\Lambda$CDM cosmologies, focusing on cosmological parameters that are independent Hubble parameter $h$. Our recovered value RMS linear perturbation theory variance as measured...
We analyse the full shape of anisotropic clustering measurements from extended Baryon Oscillation Spectroscopic survey (eBOSS) quasar sample together with combined galaxy Survey (BOSS). obtain constraints on cosmological parameters independent Hubble parameter $h$ for extensions $\Lambda$CDM models, focusing cosmologies free dark energy equation state $w$. combine those latest CMB data Planck to joint these $w$ and additional extension - its time evolution $w_{\rm{a}}$, physical curvature...
We present the analysis of halo bispectrum in redshift-space terms its multipoles, monopole, quadrupole and hexadecapole, measured from a large set simulations. fit such measurements with tree-level model perturbation theory that depends on linear nonlinear bias parameters as well growth rate $f$ density fluctuations. The likelihood takes advantage very mock catalogs, enabling robust estimation covariance properties for all multipoles. compare numerical estimate matrix to Gaussian prediction...
Combination of the power spectrum and bispectrum is a powerful way breaking degeneracies between galaxy bias cosmological parameters, enabling us to maximize constraining from surveys. Recent constraints treat on an uneven footing: they include one-loop corrections for but not bispectrum. To bridge this gap, we develop description up fourth order in perturbation theory, conveniently expressed through basis Galilean invariants that clearly split contributions are local nonlocal second...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
Our current understanding of the Universe is established through pristine measurements structure in cosmic microwave background (CMB) and distribution shapes galaxies tracing large scale (LSS) Universe. One key ingredient that underlies cosmological observables field sources observed assumed to be initially Gaussian with high precision. Nevertheless, a minimal deviation from Gaussianityis perhaps most robust theoretical prediction models explain Universe; itis necessarily present even...
Abstract Shortly after its discovery, General Relativity (GR) was applied to predict the behavior of our Universe on largest scales, and later became foundation modern cosmology. Its validity has been verified a range scales environments from Solar system merging black holes. However, experimental confirmations GR cosmological have so far lacked accuracy one would hope for — applications those being largely based extrapolation there sometimes questioned in shadow discovery unexpected cosmic...
Abstract Redshift-space distortions (RSDs) present a significant challenge in building models for the three-point correlation function (3PCF). We compare two possible lines of attack: streaming model and standard perturbation theory (SPT). The approaches differ their treatment non-linear mapping from real to redshift space: SPT expands this perturbatively, while retains its form but relies on simplifying assumptions about probability density (PDF) line-of-sight velocity differences between...
We test the regime of validity one-loop galaxy bias for a wide variety biased tracers. Our most stringent asks model to simultaneously match galaxy-galaxy and galaxy-mass spectrum, using measured nonlinear matter spectrum from simulations effects expansion alone. In addition, we investigate relevance short-range nonlocality halo exclusion through higher-derivative scale-dependent noise terms, as well impact co-evolution relations reduce number free fitting parameters. From comparing merit...
We investigate the accuracy of perturbative galaxy bias expansion in view forthcoming analysis Euclid spectroscopic samples. compare performance a Eulerian using state-of-the-art prescriptions from effective field theory large-scale structure (EFTofLSS) with hybrid approach based on Lagrangian perturbation and high-resolution simulations. These models are benchmarked against comoving snapshots flagship I N -body simulation at z = (0.9, 1.2, 1.5, 1.8), which have been populated H α galaxies...
Redshift-space distortions (RSD), caused by the peculiar velocities of galaxies, are a key modelling challenge in galaxy clustering analyses, limiting scales from which cosmological information can be reliably extracted. Unlike dynamical or bias effects, RSD imprint features that sensitive to non-linearities across all scales. Yet, no distinction between these effects is made state-of-the-art analytical approach - effective field theory (EFT) applies same perturbative expansion each them....
Over the next decade, improvements in cosmological parameter constraints will be driven by surveys of large-scale structure. Its inherent non-linearity suggests that significant information embedded higher correlations beyond two-point function. Extracting this is extremely challenging: it requires accurate theoretical modelling and computational resources to estimate covariance matrix describing between different Fourier configurations. We investigate whether possible reduce without loss...
ABSTRACT In this series of papers, we present an emulator-based halo model for the non-linear clustering galaxies in modified gravity cosmologies. first paper, emulators following properties: mass function, concentration–mass relation and halo-matter cross-correlation function. The are trained on data extracted from forge bridge suites N-body simulations, respectively, two (MG) theories: f(R) gravity, DGP model, varying three standard cosmological parameters Ωm0, H0, σ8, one MG parameter,...
ABSTRACT In this series of papers, we present a simulation-based model for the non-linear clustering galaxies based on separate modelling in real space and velocity statistics. first paper, an emulator real-space correlation function galaxies, whereas real-to-redshift mapping statistics is presented second paper. Here, show that neural network galaxy trained data extracted from dark quest suite N-body simulations achieves sub-per cent accuracies scales 1 < r 30 $h^{-1} \,...
Abstract The study of higher-order statistics, particularly 3-point the Large Scale Structure (LSS) Universe provides us with unique information on biasing relation between luminous and dark matter deviations from primordial Gaussianity. As a result, much effort has been put into improving measurement techniques as well theoretical modelling, especially in Fourier space. Comparatively, little progress made, instead, configuration space analyses. This work represents first step towards...
To understand the nature of accelerated expansion Universe, we need to combine constraints on rate and growth structure. The is usually extracted from three dimensional galaxy maps by exploiting effects peculiar motions clustering. However, theoretical models probability distribution function (PDF) pairwise velocities are not accurate enough small scales reduce error predictions level required match precision expected for measurements future surveys. Here, improve modelling velocity using...
This is the third paper in an extended study (see Phys. Rev. D 102, 103530 and 103, 123550) of impact galaxy bias modeling on extraction cosmological parameters from large scale structure. Galaxy describes possibility that galaxies do not faithfully trace distribution mass Universe this relationship. The authors comprehensively goodness range validity different models go beyond leading order by testing them against simulated samples have clustering properties several real data catalogs....
We consider an alternative to conventional three-point statistics such as the bispectrum, which is purely based on Fourier phases of density field: line correlation function. This statistic directly probes non-linear clustering regime and contains information highly complementary that contained in power spectrum. In this work, we determine, for first time, its potential constrain cosmological parameters detect baryon acoustic oscillations (hereafter BAOs). show how compute function a...
We propose an anisotropic generalization of the line correlation function (ALCF) to separate and quantify phase information in large-scale structure galaxies. The probes strictly non-linear regime formation since drops out power spectrum, provides a complementary tool commonly used techniques based on two-point statistics. Furthermore, it is independent linear bias as well Gaussian variance modulus density field thus may also prove be advantageous compared bispectrum or similar higher order...
ABSTRACT In this paper, we present COMET, a Gaussian process emulator of the galaxy power spectrum multipoles in redshift space. The model predictions are based on one-loop perturbation theory and consider two alternative descriptions redshift-space distortions: one that performs full expansion real- to mapping, as recent effective field models, another preserves non-perturbative impact small-scale velocities by means an damping function. outputs COMET can be obtained at arbitrary redshifts,...
The expansion of the Universe is understood to have accelerated during two epochs: in its very first moments a period Inflation and much more recently, at $z < 1$, when Dark Energy hypothesized drive cosmic acceleration. undiscovered mechanisms behind these epochs represent some most important open problems fundamental physics. large cosmological volume $2 z 5$, together with ability efficiently target high-$z$ galaxies known techniques, enables gains study Energy. A future spectroscopic...
ABSTRACT The coming generation of galaxy surveys will provide measurements clustering with unprecedented accuracy and data size, which allow us to test cosmological models at much higher precision than achievable previously. This means that we must have more accurate theoretical predictions compare future observational data. As a first step towards modelling the redshift space distortions (RSD) small-scale in modified gravity (MG) cosmologies, investigate validity so-called Skew-T (ST)...