A5066864672- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Statistical Mechanics and Entropy
- Advanced Statistical Methods and Models
- Stellar, planetary, and galactic studies
- Gaussian Processes and Bayesian Inference
- Astrophysics and Cosmic Phenomena
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- Statistical and numerical algorithms
- Dark Matter and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Astronomical Observations and Instrumentation
- Remote Sensing in Agriculture
- Black Holes and Theoretical Physics
- Scientific Research and Discoveries
- Computational Drug Discovery Methods
- Spectroscopy and Chemometric Analyses
- Meteorological Phenomena and Simulations
- Analytical Chemistry and Chromatography
- Fault Detection and Control Systems
Ruhr University Bochum
2021-2024
University of Bonn
2024
University of Hull
2023
Technion – Israel Institute of Technology
2019-2021
Open University of Israel
2019-2021
Heidelberg University
2015-2021
Karlsruhe Institute of Technology
2019-2021
We present a simulation-based inference (SBI) cosmological analysis of cosmic shear two-point statistics from the fourth weak gravitational lensing data release ESO Kilo-Degree Survey (KiDS-1000). KiDS-SBI efficiently performs non-Limber projection matter power spectrum via Levin 's method and constructs log-normal random fields on curved sky for arbitrary cosmologies, including effective prescriptions intrinsic alignments baryonic feedback. The forward model samples realistic galaxy...
Fast radio bursts (FRBs) are very short and bright transients visible over extragalactic distances. The pulse undergoes dispersion caused by free electrons along the line of sight, most which associated with large-scale structure (LSS). total measure therefore increases sight provides a distance estimate to source. We present first measurement Hubble constant using -- redshift relation FRBs identified host counterpart corresponding information. A sample nine currently available yields...
We introduce OneCovariance an open-source software designed to accurately compute covariance matrices for arbitrary set of two-point summary statistics across a variety large-scale structure tracers. Utilising the halo model, we estimated statistical properties matter and biased tracer fields, incorporating all Gaussian, non-Gaussian, super-sample terms. The flexible configuration permits user-specific parameters, such as complexity survey geometry, occupation distribution employed define...
ABSTRACT We present constraints on Horndeski gravity from a combined analysis of cosmic shear, galaxy–galaxy lensing and galaxy clustering $450\, \mathrm{deg}^2$ the Kilo-Degree Survey Galaxy And Mass Assembly survey.The class dark energy/modified models includes majority universally coupled extensions to ΛCDM with one scalar field in addition metric. study functions time that fully describe evolution linear perturbations gravity. Our results are compatible throughout model. By imposing...
We present constraints on the flat $\Lambda$CDM cosmological model through a joint analysis of galaxy abundance, clustering and galaxy-galaxy lensing observables with Kilo-Degree Survey. Our theoretical combines flexible conditional stellar mass function, to describe galaxy-halo connection, N-body simulation-calibrated halo non-linear matter field. magnitude-limited bright sample 9-band optical-to-near-infrared photometry an extensive complete spectroscopic training provide accurate redshift...
We present refined cosmological parameter constraints derived from a cosmic shear analysis of the fourth data release Kilo-Degree Survey (KiDS-1000). Our main improvements include enhanced galaxy shape measurements made possible by an updated version lens fit code and improved calibration achieved with newly developed suite multi-band image simulations. Additionally, we incorporated recent advancements in inference joint Dark Energy Year 3 KiDS-1000 analysis. Assuming spatially flat standard...
ABSTRACT Developing analysis pipelines based on statistics beyond two-point functions is critical for extracting a maximal amount of cosmological information from current and upcoming weak lensing surveys. In this paper, we study the impact intrinsic alignment galaxies (IA) three promising probes measured aperture mass maps – peaks, minima, full PDF. Our 2D IA infusion method converts light-cone-projected sheets into projected tidal tensors, which are then linearly coupled to an ellipticity...
Fast Radio Bursts (FRBs) are a sensitive probe of the electron distribution in both large-scale structure and their host galaxies through dispersion measure (DM) radio pulse. Baryonic feedback models crucial for modelling small scales ongoing cosmological surveys that expected to change way can be probed by FRB observations. In this paper, we explore impact baryonic on hosts using numerical simulations make detailed study galaxy as function redshift, type, model how these properties vary...
Cosmic shear is one of the primary probes to test gravity with current and future surveys. There are two main techniques analyse a cosmic survey; tomographic method, where correlations between lensing signal in different redshift bins used recover information, 3D approach, full information carried through entire analysis. Here we compare methods, by forecasting cosmological constraints for surveys like Euclid. We extend formalism first time theories beyond standard model, belonging Horndeski...
We present a simulation-based inference (SBI) cosmological analysis of cosmic shear two-point statistics from the fourth weak gravitational lensing data release ESO Kilo-Degree Survey (KiDS-1000). KiDS-SBI efficiently performs non-Limber projection matter power spectrum via Levin's method, and constructs log-normal random fields on curved sky for arbitrary cosmologies, including effective prescriptions intrinsic alignments baryonic feedback. The forward model samples realistic galaxy...
The rapidly increasing statistical power of cosmological imaging surveys requires us to reassess the regime validity for various approximations that accelerate calculation relevant theoretical predictions. In this paper, we present results 'N5K non-Limber integration challenge', goal which was quantify performance different approaches calculating angular spectrum galaxy number counts and cosmic shear data without invoking so-called 'Limber approximation', in context Rubin Observatory Legacy...
Photometric galaxy surveys, despite their limited resolution along the line of sight, encode rich information about large-scale structure (LSS) Universe thanks to high number density and extensive depth data. However, complicated selection effects in wide deep surveys can potentially cause significant bias angular two-point correlation function (2PCF) measured from those surveys. In this paper, we measure 2PCF newly published KiDS-Legacy sample. Given an r-band $5σ$ magnitude limit $24.8$...
Integrals involving highly oscillatory Bessel functions are notoriously challenging to compute using conventional integration techniques. While several methods available, they predominantly cater integrals with at most a single function, resulting in specialised yet optimised solutions. Here we present pylevin, Python package efficiently containing up three of arbitrary order and arguments. The implementation makes use Levin's method allows for accurate fast these integrals. In benchmarking...
Future observations of the large-scale structure have potential to investigate cosmological models with a high degree complexity, including properties gravity on large scales, presence complicated dark energy component, and addition neutrinos changing structures small scales. Here we study Horndeski theories gravity, most general minimally coupled scalar-tensor second order. While background evolution can be described by an effective equation state, perturbations are characterised four free...
We assume that dark matter is comprised of axion-like particles (ALPs) generated by the realignment mechanism in post-inflationary scenario. This leads to isocurvature fluctuations with an amplitude order one for scales comparable horizon at time when ALP field starts oscillating. The power spectrum these flat small wave numbers, extending relevant cosmological observables. Denoting relative $k_*$ = 0.05 Mpc$^{-1}$ $f_{\rm iso}$, Planck observations cosmic microwave background (CMB) yield...
Fast Radio Bursts (FRBs) are short astrophysical transients of extragalactic origin. Their burst signal is dispersed by the free electrons in large-scale-structure (LSS), leading to delayed arrival times at different frequencies. Another potential source time delay well known Shapiro delay, which measures space-space and time-time metric perturbations along line-of-sight. If photons frequencies follow trajectories, i.e. if universality fall guaranteed weak equivalence principle (WEP)...
Fast radio bursts (FRBs) are astrophysical transients of currently unknown origin, and so far several events have been detected at extragalactic distances. The dispersion measure (DM) the signal is a probe integrated electron density along line sight therefore allows to map distribution within large-scale structure. Since fraction electrons gets expelled from galaxies by feedback, they anticorrelated with halos large scales hence angular DM correlations show scale-dependent bias caused...
The superposition of many astrophysical gravitational wave (GW) signals below typical detection thresholds baths detectors in a stochastic background (SGWB). In this work, we present Fourier space approach to compute the frequency-domain distribution backgrounds produced by discrete sources. Expressions for moment-generating function and observed (discrete) modes are provided. results first applied signal originating from all mergers compact stellar remnants (black holes neutron stars)...
We present the final data release of Kilo-Degree Survey (KiDS-DR5), a public European Southern Observatory (ESO) wide-field imaging survey optimised for weak gravitational lensing studies. combined matched-depth multi-wavelength observations from VLT Telescope and VISTA Kilo-degree INfrared Galaxy (VIKING) to create nine-band optical-to-near-infrared spanning 1347 deg 2 . The median r -band 5 σ limiting magnitude is 24.8 with seeing 0.7″. main footprint includes 4 overlap existing deep...
The statistics of peaks in weak gravitational lensing maps is a promising technique to constrain cosmological parameters present and future surveys. Here we investigate its power when using general extreme value which very sensitive the exponential tail halo mass function. To this end, use an analytic method quantify number caused by galaxy clusters, large-scale structures observational noise. Doing so, further improve regime high signal-to-noise ratios dominated non-linear accounting for...
The coalescence of compact binary stars is expected to produce a stochastic background gravitational waves (GWs) observable with future GW detectors. Such backgrounds are usually characterized by their power spectrum as function the frequency. Here, we present method calculate full one-point distribution strain fluctuations. We focus on time series data, but our approach generalizes frequency domain. illustrate how this probability can be evaluated numerically. In addition, derive accurate...
We determine the error introduced in a joint halo model analysis of galaxy-galaxy lensing and galaxy clustering observables when adopting standard approximation linear bias. Considering Kilo-Degree Survey, we forecast that ignoring non-linear bias would result up to 5$\sigma$ offsets recovered cosmological parameters describing structure growth, $S_8$, matter density parameter, $\Omega_{\mathrm{m}}$. include scales $10^{-1.3}<r_{\rm{p}} \ / h^{-1}\, \mathrm{Mpc}<10$ data vector, direction...
The likelihood function for cosmological parameters, given by e.g. weak lensing shear measurements, depends on contributions to the covariance induced non-linear evolution of cosmic web. As highly clustering date has only been described numerical N-body simulations in a reliable and sufficiently precise way, necessary computational costs estimating those covariances at different points parameter space are tremendous. In this work, we describe change matter matrix as parameters constructing...
Forecasts in cosmology, both with Monte-Carlo Markov-chain methods and the Fisher matrix formalism, depend on choice of fiducial model because signal strength any observable as well nonlinearities linking observables to cosmological parameters vary general case. In this paper we propose a method for extrapolating Fisher-forecasts across space by constructing suitable ba- sis. We demonstrate validity our constraints standard dark energy extrapolated from {\Lambda}CDM-model, can be expected...
We study the spherical collapse model in presence of external gravitational tidal shear fields for different dark energy scenarios and investigate impact on mass function cluster number counts. While previous studies influence rotation δc have been performed with heuristically motivated models, we try to avoid this dependence sample values directly from statistics underlying linearly evolved density field based first-order Lagrangian perturbation theory. Within self-consistent approach,...