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Inferring cosmological parameters from time-delay strong lenses requires a significant investment of telescope time; it is therefore tempting to focus on the systems with the brightest sources, the highest image multiplicities and the…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-07 Thomas E. Collett , Steven D. Cunnington

Gravitational lensing causes a correlation between a population of foreground large-scale structures and the observed number density of the background distant galaxies as a consequence of the flux magnification and the lensing area…

Astrophysics · Physics 2009-11-06 Takashi Hamana

We report a measurement of cosmic shear correlations using an effective area of 6.5 sq. deg. of the VIRMOS deep imaging survey in progress at the Canada-France-Hawaii Telescope. We measured various shear correlation functions, the aperture…

Weak lensing experiments are a powerful probe of cosmology through their measurement of the mass distribution of the universe. A challenge for this technique is to control systematic errors that occur when measuring the shapes of distant…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Alexandre Refregier , Tomasz Kacprzak , Adam Amara , Sarah Bridle , Barnaby Rowe

The ability to remove features from the input of machine learning models is very important to understand and interpret model predictions. However, this is non-trivial for vision models since masking out parts of the input image typically…

Computer Vision and Pattern Recognition · Computer Science 2023-10-31 Sriram Balasubramanian , Soheil Feizi

This paper presents the first application of 3D cosmic shear to a wide-field weak lensing survey. 3D cosmic shear is a technique that analyses weak lensing in three dimensions using a spherical harmonic approach, and does not bin data in…

In this paper we derive a full expression for the propagation of weak lensing shape measurement biases into cosmic shear power spectra including the effect of missing data. We show using simulations that terms higher than first order in…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-16 T. D. Kitching , A. C. Deshpande , P. L. Taylor

The VST Optical Imaging of the CDFS and ES1 Fields (VOICE) Survey is proposed to obtain deep optical $ugri$ imaging of the CDFS and ES1 fields using the VLT Survey Telescope (VST). At present, the observations for the CDFS field have been…

We use statistical inference theory to explore the constraints from future galaxy weak lensing (cosmic shear) surveys combined with the current CMB constraints on cosmological parameters, focusing particularly on the running of the spectral…

Astrophysics · Physics 2009-11-10 Mustapha Ishak , Christopher M. Hirata , Patrick McDonald , Uros Seljak

Upcoming weak lensing surveys will survey large cosmological volumes to measure the growth of cosmological structure with time and thereby constrain dark energy. One major systematic uncertainty in this process is the calibration of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Arun Kannawadi , Rachel Mandelbaum , Claire Lackner

Deep learning is a powerful analysis technique that has recently been proposed as a method to constrain cosmological parameters from weak lensing mass maps. Due to its ability to learn relevant features from the data, it is able to extract…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-26 Janis Fluri , Tomasz Kacprzak , Aurelien Lucchi , Alexandre Refregier , Adam Amara , Thomas Hofmann

The ratio between the CMB lensing/galaxy counts and the galaxy shear/galaxy counts cross-correlations combines the information from different cosmological probes to infer cosmographic measurements that are less dependent on astrophysical…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-08 José Ramón Bermejo-Climent , Mario Ballardini , Fabio Finelli , Vincenzo Fabrizio Cardone

We present a cosmic shear analysis of the 100 square degree weak lensing survey, combining data from the CFHTLS-Wide, RCS, VIRMOS-DESCART and GaBoDS surveys. Spanning ~100 square degrees, with a median source redshift z~0.78, this combined…

Accurate knowledge of the effect of feedback from galaxy formation on the matter distribution is a key requirement for future weak lensing experiments. Recent studies using hydrodynamic simulations have shown that different baryonic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Elisabetta Semboloni , Henk Hoekstra , Joop Schaye

We present a mitigation strategy to reduce the impact of non-linear galaxy bias on the joint `$3 \times 2 $pt' cosmological analysis of weak lensing and galaxy surveys. The $\Psi$-statistics that we adopt are based on Complete Orthogonal…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-16 Marika Asgari , Indiarose Friswell , Mijin Yoon , Catherine Heymans , Andrej Dvornik , Benjamin Joachimi , Patrick Simon , Joe Zuntz

We apply a mass reconstruction technique to simulated large-scale structure gravitational distortion maps, from 2.5' to 10 degree scales, for different cosmological scenarii. The projected mass is reconstructed using a non-parametric least…

Astrophysics · Physics 2007-05-23 L. Van Waerbeke , F. Bernardeau , Y. Mellier

Owing to their more extensive sky coverage and tighter control on systematic errors, future deep weak lensing surveys should provide a better statistical picture of the dark matter clustering beyond the level of the power spectrum. In this…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Dipak Munshi , Joseph Smidt , Alan Heavens , Peter Coles , Asantha Cooray

We quantify two main pathways through which baryonic physics biases cluster count cosmology. We create mock cluster samples that reproduce the baryon content inferred from X-ray observations. We link clusters to their counterparts in a dark…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-22 Stijn N. B. Debackere , Joop Schaye , Henk Hoekstra

We use matter power spectra from cosmological hydrodynamic simulations to quantify the effect of baryon physics on the weak gravitational lensing shear signal. The simulations consider a number of processes, such as radiative cooling, star…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Elisabetta Semboloni , Henk Hoekstra , Joop Schaye , Marcel P. van Daalen , Ian G. McCarthy

Convolutional Neural Networks (CNNs) have recently been applied to cosmological fields -- weak lensing mass maps and galaxy maps. However, cosmological maps differ in several ways from the vast majority of images that CNNs have been tested…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-05 Kunhao Zhong , Marco Gatti , Bhuvnesh Jain
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