Publications de Thibault Adrien Kuntzer

Weak-lensing shear measurement with machine learning Teaching artificial neural networks about feature noise

Frédéric Courbin, Thibault Adrien Kuntzer, Malte Tewes, Nicolai Hildebrandt

Cosmic shear, that is weak gravitational lensing by the large-scale matter structure of the Universe, is a primary cosmological probe for several present and upcoming surveys investigating dark matter and dark energy, such as Euclid or WFIRST. The probe re ...

EDP SCIENCES S A2019

Deep convolutional neural networks as strong gravitational lens detectors

Jean-Paul Richard Kneib, Thibault Adrien Kuntzer

2018

Machine-learning methods for weak lensing analysis of the ESA Euclid sky survey

Thibault Adrien Kuntzer

A clear picture has emerged from the last three decades of research: our Universe is expanding at an accelerated rate. The cause of this expansion remains elusive, but in essence acts as a repulsive force. This so-called dark energy represents about 69% of ...

EPFL2018

Detecting unresolved binary stars in Euclid VIS images

Frédéric Courbin, Thibault Adrien Kuntzer

Measuring a weak gravitational lensing signal to the level required by the next generation of space-based surveys demands exquisite reconstruction of the point-spread function (PSF). However, unresolved binary stars can significantly distort the PSF shape. ...

Edp Sciences S A2017

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XV. Assessing the achievability and precision of time-delay measurements

Frédéric Courbin, Georges Meylan, Thibault Adrien Kuntzer, Malte Tewes, Vivien François Bonvin

COSMOGRAIL is a long-term photometric monitoring of gravitationally lensed quasars aimed at implementing Refsdal's time-delay method to measure cosmological parameters, in particular H-0. Given the long and well sampled light curves of strongly lensed quas ...

Edp Sciences S A2016

Stellar classification from single-band imaging using machine learning

Frédéric Courbin, Thibault Adrien Kuntzer, Malte Tewes

Information on the spectral types of stars is of great interest in view of the exploitation of space-based imaging surveys. In this article, we investigate the classification of stars into spectral types using only the shape of their diffraction pattern in ...

Edp Sciences S A2016

Evaluating the effect of stellar multiplicity on the point spread function of space-based weak lensing surveys

Frédéric Courbin, Georges Meylan, Thibault Adrien Kuntzer

The next generation of space-based telescopes used for weak lensing surveys will require exquisite point spread function (PSF) determination. Previously negligible effects may become important in the reconstruction of the PSF, in part because of the improv ...

Edp Sciences S A2016

GREAT3 results - I. Systematic errors in shear estimation and the impact of real galaxy morphology

Frédéric Courbin, Thibault Adrien Kuntzer, Jean-Luc Starck, Malte Tewes, Huanyuan Shan, Marc Gentile, Guldariya Nurbaeva, Jun Zhang

We present first results from the third GRavitational lEnsing Accuracy Testing (GREAT3) challenge, the third in a sequence of challenges for testing methods of inferring weak gravitational lensing shear distortions from simulated galaxy images. GREAT3 was ...

Oxford University Press2015

SALSA: a tool to estimate the stray light contamination for low-Earth orbit observatories

Thibault Adrien Kuntzer

Stray light contamination reduces considerably the precision of photometric of faint stars for low altitude space-borne observatories. When measuring faint objects, the necessity of coping with stray light contamination arises in order to avoid systematic ...

Spie-Int Soc Optical Engineering2014