Results 21 to 30 of about 206 (178)
An Unbiased Method of Measuring the Ratio of Two Data Sets
The Astrophysical Journal Supplement Series, 2023 In certain cases of astronomical data analysis, the meaningful physical quantity to extract is the ratio R between two data sets. Examples include the lensing ratio, the interloper rate in spectroscopic redshift samples, and the decay rate of ...
Zeyang Sun +7 more
doaj +1 more source
Weak gravitational lensing shear measurement with FPFS: analytical mitigation of noise bias and selection bias [PDF]
Monthly Notices of the Royal Astronomical Society, 2022 ABSTRACT Dedicated ‘Stage IV’ observatories will soon observe the entire extragalactic sky, to measure the ‘cosmic shear’ distortion of galaxy shapes by weak gravitational lensing. To measure the apparent shapes of those galaxies, we present an improved version of the Fourier Power Function Shapelets (FPFS) shear measurement method. This
Xiangchong Li, Yin Li, Richard Massey
openaire +4 more sources
Means of confusion: how pixel noise affects shear estimates for weak gravitational lensing [PDF]
Monthly Notices of the Royal Astronomical Society, 2012 integrated the origin of the moment correlation (thanks to Alan Heavens).
Melchior, P., Viola, M.
openaire +4 more sources
Monthly Notices of the Royal Astronomical Society, 2022 ABSTRACT We investigate the performance of the metacalibration shear calibration framework using simulated imaging data for the Nancy Grace Roman Space Telescope (Roman) reference High-Latitude Imaging Survey (HLIS). The weak lensing programme of Roman requires the mean weak lensing shear estimate to be calibrated within about 0.03 per ...
Masaya Yamamoto +7 more
openaire +3 more sources
The Astrophysical Journal, 2022 Abstract We study the gravitational lensing influence of a massive object in a dark matter halo, using a simple model of a point mass embedded in a spherical Navarro–Frenk–White halo. Building on the analysis of critical curves and caustics presented in the first part of this work, we proceed to explore the geometry of images formed by ...
Michal Karamazov, David Heyrovský
openaire +2 more sources
Gravitational lensing shear by an exotic lens object with negative convergence or negative mass [PDF]
Physical Review D, 2013 Gravitational lens models with negative convergence(surface mass density projected onto the lens plane) inspired by modified gravity theories, exotic matter and energy have been recently discussed in such a way that a static and spherically-symmetric modified spacetime metric depends on the inverse distance to the power of positive $n$(n=1 for ...
Izumi, Koji +4 more
openaire +2 more sources
The imprint of f(R) gravity on weak gravitational lensing – II. Information content in cosmic shear statistics [PDF]
Monthly Notices of the Royal Astronomical Society, 2016 We investigate the information content of various cosmic shear statistics on the theory of gravity. Focusing on the Hu-Sawicki-type $f(R)$ model, we perform a set of ray-tracing simulations and measure the convergence bispectrum, peak counts and Minkowski functionals.
Shirasaki, Masato +3 more
openaire +3 more sources
Metadetection Weak Lensing for the Vera C. Rubin Observatory
The Open Journal of Astrophysics, 2023 Forthcoming astronomical imaging surveys will use weak gravitational lensing shear as a primary probe to study dark energy, with accuracy requirements at the 0.1% level.
Erin S. Sheldon +4 more
doaj +1 more source
Simulations of weak gravitational lensing – II. Including finite support effects in cosmic shear covariance matrices [PDF]
Monthly Notices of the Royal Astronomical Society, 2015 (Abridged) We investigate and quantify the impact of finite simulation volume on weak lensing two- and four-point statistics. These {\it finite support} (FS) effects are modelled for several estimators, simulation box sizes and source redshifts, and validated against a new large suite of 500 $N$-body simulations.
Harnois-Déraps, J, van Waerbeke, L
openaire +2 more sources
Source Distributions of Cosmic Shear Surveys in Efficiency Space
The Open Journal of Astrophysics, 2020 We show that the lensing efficiency of cosmic shear generically has a simple shape, even in the case of a tomographic survey with badly behaved photometric redshifts.
Nicolas Tessore, Ian Harrison
doaj +1 more source