Home

Person

Georges Meylan

About
Privacy
Disclaimer

Graph Chatbot

Related publications (182)

Euclid: Cosmology forecasts from the void-galaxy cross-correlation function with reconstruction

Georges Meylan, Frédéric Courbin, Richard Massey, Yi Wang

We have investigated the cosmological constraints that can be expected from measurement of the cross-correlation of galaxies with cosmic voids identified in the Euclid spectroscopic survey, which will include spectroscopic information for tens of millions ...

EDP SCIENCES S A2023

Euclid: modelling massive neutrinos in cosmology a code comparison

Georges Meylan, Richard Massey, Bo Li, Yi Wang

The measurement of the absolute neutrino mass scale from cosmological largescale clustering data is one of the key science goals of the Euclid mission. Such a measurement relies on precise modelling of the impact of neutrinos on structure formation, which ...

Iop Publishing Ltd2023

Euclid preparation - XXIII. Derivation of galaxy physical properties with deep machine learning using mock fluxes and H-band images

Robin Humphry-Baker, Georges Meylan, Frédéric Courbin, Richard Massey, Maurizio Martinelli, Gianluca Castignani, Marcello Farina, Austin Chandler Peel, Yi Wang

Next-generation telescopes, like Euclid, Rubin/LSST, and Roman, will open new windows on the Universe, allowing us to infer physical properties for tens of millions of galaxies. Machine-learning methods are increasingly becoming the most efficient tools to ...

OXFORD UNIV PRESS2023

Euclid preparation XXV. The Euclid Morphology Challenge: Towards model-fitting photometry for billions of galaxies

Georges Meylan, Frédéric Courbin

The European Space Agency's Euclid mission will provide high-quality imaging for about 1.5 billion galaxies. A software pipeline to automatically process and analyse such a huge amount of data in real time is being developed by the Science Ground Segment o ...

EDP SCIENCES S A2023

Euclid preparation XX. The Complete Calibration of the Color-Redshift Relation survey: LBT observations and data release

Georges Meylan, Frédéric Courbin

The Complete Calibration of the Color-Redshift Relation survey (C3R2) is a spectroscopic program designed to empirically calibrate the galaxy color-redshift relation to the Euclid depth (I-E = 24.5), a key ingredient for the success of Stage IV dark energy ...

EDP SCIENCES S A2022

Euclid: Searching for pair-instability supernovae with the Deep Survey

Georges Meylan, Frédéric Courbin, Giovanni Longo, Richard Massey, Yi Wang

Pair-instability supernovae are theorized supernovae that have not yet been observationally confirmed. They are predicted to exist in low-metallicity environments. Because overall metallicity becomes lower at higher redshifts, deep near-infrared transient ...

EDP SCIENCES S A2022

KiDS and Euclid: Cosmological implications of a pseudo angular power spectrum analysis of KiDS-1000 cosmic shear tomography

Georges Meylan, Huanyuan Shan, Richard Massey, Jean-Luc Starck, Yi Wang

We present a tomographic weak lensing analysis of the Kilo Degree Survey Data Release 4 (KiDS-1000), using a new pseudo angular power spectrum estimator (pseudo-C-l) under development for the ESA Euclid mission. Over 21 million galaxies with shape informat ...

EDP SCIENCES S A2022

Euclid preparation XIII. Forecasts for galaxy morphology with the Euclid Survey using deep generative models

Georges Meylan

We present a machine learning framework to simulate realistic galaxies for the Euclid Survey, producing more complex and realistic galaxies than the analytical simulations currently used in Euclid. The proposed method combines a control on galaxy shape par ...

EDP SCIENCES S A2022

Euclid preparation I. The Euclid Wide Survey

Georges Meylan, Frédéric Courbin

Euclid is a mission of the European Space Agency that is designed to constrain the properties of dark energy and gravity via weak gravitational lensing and galaxy clustering. It will carry out a wide area imaging and spectroscopy survey (the Euclid Wide Su ...

EDP SCIENCES S A2022

Euclid preparation XV. Forecasting cosmological constraints for the Euclid and CMB joint analysis

Georges Meylan

The combination and cross-correlation of the upcoming Euclid data with cosmic microwave background (CMB) measurements is a source of great expectation since it will provide the largest lever arm of epochs, ranging from recombination to structure formation ...

EDP SCIENCES S A2022

Euclid preparation XXI. Intermediate-redshift contaminants in the search for z > 6 galaxies within the Euclid Deep Survey

Georges Meylan, Frédéric Courbin, Hakim Atek, Richard Massey, Maurizio Martinelli, Jean-Luc Starck, Gianluca Castignani, Marcello Farina, Austin Chandler Peel, Yi Wang

Context. The Euclid mission is expected to discover thousands of z > 6 galaxies in three deep fields, which together will cover a similar to 50 deg(2) area. However, the limited number of Euclid bands (four) and the low availability of ancillary data could ...

EDP SCIENCES S A2022

Euclid: Cosmological forecasts from the void size function

Georges Meylan, Frédéric Courbin

The Euclid mission - with its spectroscopic galaxy survey covering a sky area over 15 000 deg(2) in the redshift range 0.9 < z < 1.8 - will provide a sample of tens of thousands of cosmic voids. This paper thoroughly explores for the first time the constra ...

EDP SCIENCES S A2022

Euclid preparation XIX. Impact of magnification on photometric galaxy clustering

Georges Meylan, Frédéric Courbin

Aims. We investigate the importance of lensing magnification for estimates of galaxy clustering and its cross-correlation with shear for the photometric sample of Euclid. Using updated specifications, we study the impact of lensing magnification on the con ...

EDP SCIENCES S A2022

Euclid: Fast two-point correlation function covariance through linear construction

Georges Meylan

We present a method for fast evaluation of the covariance matrix for a two-point galaxy correlation function (2PCF) measured with the Landy-Szalay estimator. The standard way of evaluating the covariance matrix consists in running the estimator on a large ...

EDP SCIENCES S A2022

Euclid: Forecasts from redshift-space distortions and the Alcock-Paczynski test with cosmic voids

Georges Meylan

Euclid is poised to survey galaxies across a cosmological volume of unprecedented size, providing observations of more than a billion objects distributed over a third of the full sky. Approximately 20 million of these galaxies will have their spectroscopy ...

EDP SCIENCES S A2022

Euclid: Covariance of weak lensing pseudo-C-l estimates Calculation, comparison to simulations, and dependence on survey geometry

Georges Meylan

An accurate covariance matrix is essential for obtaining reliable cosmological results when using a Gaussian likelihood. In this paper we study the covariance of pseudo-C-l estimates of tomographic cosmic shear power spectra. Using two existing publicly av ...

EDP SCIENCES S A2022

Euclid: Constraining ensemble photometric redshift distributions with stacked spectroscopy

Georges Meylan

Context. The ESA Euclid mission will produce photometric galaxy samples over 15 000 square degrees of the sky that will be rich for clustering and weak lensing statistics. The accuracy of the cosmological constraints derived from these measurements will de ...

EDP SCIENCES S A2022

Euclid preparation XVIII. The NISP photometric system

Georges Meylan, Frédéric Courbin, Austin Chandler Peel

Euclid will be the first space mission to survey most of the extragalactic sky in the 0.95-2.02 mu m range, to a 5 sigma point-source median depth of 24.4 AB mag. This unique photometric dataset will find wide use beyond Euclid's core science. In this pape ...

EDP SCIENCES S A2022

Euclid: Forecast constraints on consistency tests of the ?CDM model

Georges Meylan, Frédéric Courbin

Context. The standard cosmological model is based on the fundamental assumptions of a spatially homogeneous and isotropic universe on large scales. An observational detection of a violation of these assumptions at any redshift would immediately indicate th ...

EDP SCIENCES S A2022

EAS 2022 takes positive steps forward for sustainable astronomy

Georges Meylan

2022

Page 5 of 10