Virginia Ajani
A5085739976- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Statistical and numerical algorithms
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Spaceflight effects on biology
- Particle physics theoretical and experimental studies
- Radio Astronomy Observations and Technology
- Neutrino Physics Research
- Scientific Research and Discoveries
- Monetary Policy and Economic Impact
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
ETH Zurich
2022-2025
Netherlands Institute for Radio Astronomy
2025
Astrophysique, Instrumentation et Modélisation
2020-2024
CEA Paris-Saclay
2020-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2020-2024
Université Paris-Saclay
2020-2023
Université Paris Cité
2020-2023
Centre National de la Recherche Scientifique
2020-2023
Sorbonne Paris Cité
2020-2021
Délégation Paris 7
2020
The current standard model of cosmology successfully describes a variety measurements, but the nature its main ingredients, dark matter and energy, remains unknown. is medium-class mission in Cosmic Vision 2015--2025 programme European Space Agency (ESA) that will provide high-resolution optical imaging, as well near-infrared imaging spectroscopy, over about 14\,000\,deg$^2$ extragalactic sky. In addition to accurate weak lensing clustering measurements probe structure formation half age...
Recent cosmic shear studies have shown that higher-order statistics (HOS) developed by independent teams now outperform standard two-point estimators in terms of statistical precision thanks to their sensitivity the non-Gaussian features large-scale structure. The aim Higher-Order Weak Lensing Statistics (HOWLS) project is assess, compare, and combine constraining power ten different HOS on a common set $Euclid$-like mocks, derived from N-body simulations. In this first paper HOWLS series,...
Beyond-two-point statistics contain additional information on cosmological as well astrophysical and observational (systematics) parameters. In this methodology paper we provide an end-to-end simulation-based analysis of a set Gaussian non-Gaussian weak lensing using detailed mock catalogs the Dark Energy Survey (DES). We implement: 1) second third moments; 2) wavelet phase harmonics (WPH); 3) scattering transform (ST). Our is fully based simulations, it spans space seven νwCDM parameters,...
We present a simulation-based cosmological analysis using combination of Gaussian and non-Gaussian statistics the weak lensing mass (convergence) maps from first three years (Y3) Dark Energy Survey (DES). implement: 1) second third moments; 2) wavelet phase harmonics; 3) scattering transform. Our is fully based on simulations, spans space seven $\nu w$CDM parameters, forward models most relevant sources systematics inherent in data: masks, noise variations, clustering sources, intrinsic...
ABSTRACT We measure the impact of source galaxy clustering on higher order summary statistics weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not underlying density field, we show this effect can exceed measurement uncertainties for common certain analysis choices. evaluate different observables, finding third moments and wavelet phase harmonics are more affected than peak count statistics. Using Dark Energy Survey (DES) Year 3 (Y3) data,...
Widefield surveys of the sky probe many clustered scalar fields -- such as galaxy counts, lensing potential, gas pressure, etc. that are sensitive to different cosmological and astrophysical processes. Our ability constrain processes from these depends crucially on statistics chosen summarize field. In this work, we explore cumulative distribution function (CDF) at multiple scales a summary convergence Using suite N-body lightcone simulations, show CDFs' constraining power is modestly better...
Massive neutrinos influence the background evolution of Universe as well growth structure. Being able to model this effect and constrain sum their masses is one key challenges in modern cosmology. Weak-lensing cosmological constraints will also soon reach higher levels precision with next-generation surveys like LSST, WFIRST Euclid. In context, we use massivenus simulations derive on neutrino ${M}_{\ensuremath{\nu}}$, present-day total matter density ${\mathrm{\ensuremath{\Omega}}}_{m}$,...
The next generation of weak lensing surveys will measure the matter distribution local Universe with unprecedented precision, allowing resolution non-Gaussian features convergence field. This encourages use higher-order mass-map statistics for cosmological parameter inference. We extend forward-modelling based methodology introduced in a previous forecast paper to match these new requirements. provide multiple forecasts wCDM constraints that can be expected from stage 3 and 4 surveys....
Context. The Ultraviolet Near-Infrared Optical Northern Survey (UNIONS) is an ongoing deep photometric multiband survey of the northern sky. As part UNIONS, Canada-France Imaging (CFIS) provides r -band data, which we use to study weak-lensing peak counts for cosmological inference. Aims. We assess systematic effects and their impact on parameters UNIONS survey. In particular, present results local calibration, metacalibration shear bias, baryonic feedback, source galaxy redshift estimate,...
We present a first application to photometric galaxy clustering and weak lensing of wavelet based multi-scale higher order summary statistics: starlet peak counts $\ell_1$-norm. Peak are the local maxima in map $\ell_1$-norm is computed via sum absolute values (wavelet) decomposition coefficients map, providing fast calculation pixel distribution, encoding information all pixels map. employ cosmo-SLICS simulations sources lenses catalogues we compute statistics context combined probes their...
We demonstrate and measure the impact of source galaxy clustering on higher-order summary statistics weak gravitational lensing data. By comparing simulated data with galaxies that either trace or do not underlying density field, we show this effect can exceed measurement uncertainties for common certain analysis choices. Source effects are larger at small scales applied to combinations low high redshift samples, diminish redshift. evaluate different observables, finding third moments...
The next generation of weak lensing surveys will measure the matter distribution local Universe with unprecedented precision, allowing resolution non-Gaussian features convergence field. This encourages use higher-order mass-map statistics for cosmological parameter inference. We extend forward-modelling based methodology introduced in a previous forecast paper to match these new requirements. provide multiple forecasts wCDM constraints that can be expected from stage 3 and 4 surveys....
Beyond-two-point statistics contain additional information on cosmological as well astrophysical and observational (systematics) parameters. In this methodology paper we provide an end-to-end simulation-based analysis of a set Gaussian non-Gaussian weak lensing using detailed mock catalogues the Dark Energy Survey. We implement: 1) second third moments; 2) wavelet phase harmonics (WPH); 3) scattering transform (ST). Our is fully based simulations, it spans space seven $\nu w$CDM parameters,...
UNIONS is an ongoing deep photometric multi-band survey of the Northern sky. As part UNIONS, CFIS provides r-band data which we use to study weak-lensing peak counts for cosmological inference. We assess systematic effects and their impact on parameters survey. In particular, present results local calibration, metacalibration shear bias, baryonic feedback, source galaxy redshift estimate, intrinsic alignment, cluster member dilution. For each uncertainty effect, describe our mitigation...
We present a new summary statistic for weak lensing observables, higher than second order, suitable extracting non-Gaussian cosmological information and inferring parameters. name this the 'starlet $\ell_1$-norm' as it is computed via sum of absolute values starlet (wavelet) decomposition coefficients map. In comparison to state-of-the-art higher-order statistics -- peak counts minimum counts, or combination two $\ell_1$-norm provides fast multi-scale calculation full void distribution,...