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Frédéric Courbin

Cette personne a quitté l’EPFL

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Publications associées (220)

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A sharp look at the gravitationally lensed quasar SDSS J0806+2006 with laser guide star adaptive optics at the VLT

Frédéric Courbin, Georges Meylan, Alexander Patrick Eigenbrod

We present the first VLT near-IR observations of a gravitationally lensed quasar, using adaptive optics and laser guide star. These observations can be considered as a test bench for future systematic observations of lensed quasars with adaptive optics, ev ...

2008

First case of strong gravitational lensing by a QSO: SDSS J0013+1523 at z=0.120

Frédéric Courbin, Georges Meylan, Malte Tewes, François Henri Ambroise Rérat

We present the first case of strong gravitational lensing by a QSO: SDSS J0013 + 1523 at z = 0.120. The discovery is the result of a systematic search for emission lines redshifted behind QSOs, among 22 298 spectra of the SDSS data release 7. Apart from th ...

2010

Euclid preparation: XLVII. Improving cosmological constraints using a new multi-tracer method with the spectroscopic and photometric samples

Frédéric Courbin, Georges Meylan

Future data provided by the Euclid mission will allow us to better understand the cosmic history of the Universe. A metric of its performance is the figure-of-merit (FoM) of dark energy, usually estimated with Fisher forecasts. The expected FoM has previou ...

2024

The Third Gravitational Lensing Accuracy Testing (Great3) Challenge Handbook

Frédéric Courbin, Marc Gentile

The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is the third in a series of image analysis challenges, with a goal of testing and facilitating the development of methods for analyzing astronomical images that will be used to measure weak gr ...

University of Chicago Press2014

Interpolating point spread function anisotropy

Frédéric Courbin, Georges Meylan, Marc Gentile

Planned wide-field weak lensing surveys are expected to reduce the statistical errors on the shear field to unprecedented levels. In contrast, systematic errors like those induced by the convolution with the point spread function (PSF) will not benefit fro ...

Edp Sciences S A2013

J1721+8842: a gravitationally lensed binary quasar with a proximate damped Lyman-alpha absorber

Frédéric Courbin, Martin Raoul Robert Millon, Hung-Hsu Chan, Eric Gérard Guy Paic, Cameron Alexander Campbell Lemon

High-redshift binary quasars provide key insights into mergers and quasar activity, and are useful tools for probing the spatial kinematics and chemistry of galaxies along the line of sight. However, only three sub-10-kpc binaries have been confirmed above ...

EDP SCIENCES S A2022

Search of strong lens systems in the Dark Energy Survey using convolutional neural networks

Frédéric Courbin, Hung-Hsu Chan, Cameron Alexander Campbell Lemon, Georgios Vernardos, Benjamin Yvan Alexandre Clement, Aymeric Alexandre Galan, Karina Alexandra Rojas Olate, Elodie Marie Charlène Savary

We present our search for strong lens, galaxy-scale systems in the first data release of the Dark Energy Survey (DES), based on a color-selected parent sample of 18 745 029 luminous red galaxies (LRGs). We used a convolutional neural network (CNN) to grade ...

EDP SCIENCES S A2022

H0LiCOW-V. New COSMOGRAIL time delays of HE 0435-1223: H-0 to 3.8 per cent precision from strong lensing in a flat Lambda CDM model

Frédéric Courbin, Georges Meylan, Vivien François Bonvin, Malte Tewes

We present a new measurement of the Hubble Constant H-0 and other cosmological parameters based on the joint analysis of three multiply imaged quasar systems with measured gravitational time delays. First, we measure the time delay of HE 0435-1223 from 13- ...

Oxford Univ Press2017

Euclid: Early Release Observations – The intracluster light and intracluster globular clusters of the Perseus cluster

Frédéric Courbin, Georges Meylan, Yannick Michael Bahé

We study the intracluster light (ICL) and intracluster globular clusters (ICGCs) in the nearby Perseus cluster of galaxies using Euclid’s Early Release Observations. By modelling the isophotal and iso-density contours, we mapped the distributions and prope ...

2025

Euclid preparation XLIII. Measuring detailed galaxy morphologies for Euclid with machine learning

Frédéric Courbin, Georges Meylan, Austin Chandler Peel

The Euclid mission is expected to image millions of galaxies at high resolution, providing an extensive dataset with which to study galaxy evolution. Because galaxy morphology is both a fundamental parameter and one that is hard to determine for large samp ...

2024

COSMOGRAIL: the COSmological MOnitoring of GRAvItational lenses - VII. Time delays and the Hubble constant from WFI J2033-4723

Frédéric Courbin, Georges Meylan, Christel Vuissoz

Gravitationally lensed quasars can be used to map the mass distribution in lensing galaxies and to estimate the Hubble constant H-0 by measuring the time delays between the quasar images. Here we report the measurement of two independent time delays in the ...

2008

Euclid preparation XXX. Performance assessment of the NISP red grism through spectroscopic simulations for the wide and deep surveys

Maurizio Martinelli, Frédéric Courbin, Georges Meylan, Michaela Hirschmann, Gianluca Castignani

This work focusses on the pilot run of a simulation campaign aimed at investigating the spectroscopic capabilities of the Euclid NearInfrared Spectrometer and Photometer (NISP), in terms of continuum and emission line detection in the context of galaxy evo ...

EDP SCIENCES S A2023

Constraining the low-mass end of the initial mass function with gravitational lensing

Frédéric Courbin

The low-mass end of the stellar initial mass function (IMF) is constrained by focusing on the baryon-dominated central regions of strong lensing galaxies. We study in this Letter the Einstein Cross (Q2237+0305), a z = 0.04 barred galaxy whose bulge acts as ...

2010

LensWatch. I. Resolved HST Observations and Constraints on the Strongly Lensed Type Ia Supernova 2022qmx ("SN Zwicky")

Frédéric Courbin

Supernovae (SNe) that have been multiply imaged by gravitational lensing are rare and powerful probes for cosmology. Each detection is an opportunity to develop the critical tools and methodologies needed as the sample of lensed SNe increases by orders of ...

IOP Publishing Ltd2023

Modeling lens potentials with continuous neural fields in galaxy-scale strong lenses

Frédéric Courbin, Georgios Vernardos

Strong gravitational lensing is a unique observational tool for studying the dark and luminous mass distribution both within and between galaxies. Given the presence of substructures, current strong lensing observations demand more complex mass models than ...

EDP SCIENCES S A2023

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

Euclid preparation: LXVIII. Extracting physical parameters from galaxies with machine learning

Frédéric Courbin, Georges Meylan, Olivia Mueller

The Euclid mission is generating a vast amount of imaging data in four broadband filters at a high angular resolution. This data will allow for the detailed study of mass, metallicity, and stellar populations across galaxies that will constrain their forma ...

2025

COSMOGRAIL: XIX. Time delays in 18 strongly lensed quasars from 15 years of optical monitoring star

Frédéric Courbin, Georges Meylan, Hung-Hsu Chan, Vivien François Bonvin, Malte Tewes, Martin Raoul Robert Millon, Aymeric Alexandre Galan, Rémy Elie Joseph, Eric Gérard Guy Paic, Cameron Alexander Campbell Lemon, Olga Tihhonova

We present the results of 15 years of monitoring lensed quasars, which was conducted by the COSMOGRAIL programme at the Leonhard Euler 1.2 m Swiss Telescope. The decade-long light curves of 23 lensed systems are presented for the first time. We complement ...

EDP SCIENCES S A2020

A SHARP view of H0LiCOW: H-0 from three time-delay gravitational lens systems with adaptive optics imaging

Frédéric Courbin, Hung-Hsu Chan, Vivien François Bonvin, Martin Raoul Robert Millon

We present the measurement of the Hubble constant, H-0, with three strong gravitational lens systems, We describe a blind analysis of both PG 1115+080 and 11E0435-1223 as well as an extension of our previous analysis of RXJ 1131-1231. For each lens, we com ...

OXFORD UNIV PRESS2019

Stellar classification from single-band imaging using machine learning

Frédéric Courbin, Malte Tewes, Thibault Adrien Kuntzer

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