Publications by Georges Meylan

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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 ...

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 ...

We present detailed modelling of the recently discovered, quadruply lensed quasar J0408-5354, with the aim of interpreting its remarkable configuration: besides three quasar images (A, B, D) around the main deflector (G1), a fourth image (C) is significant ...

The Near-Infrared Spectrometer and Photometer (NISP) on board the Euclid satellite provides multiband photometry and R âÂ ³ 450 slitless grism spectroscopy in the 950- 2020 nm wavelength range. In this reference article, we illuminate the background of NIS ...

We present new measurements of the time delays of WFI2033-4723. The data sets used in this work include 14 years of data taken at the 1.2 m Leonhard Euler Swiss telescope, 13 years of data from the SMARTS 1.3 m telescope at Las Campanas Observatory and a s ...

In physically realistic, scalar-field-based dynamical dark energy models (including, e.g., quintessence), one naturally expects the scalar field to couple to the rest of the model's degrees of freedom. In particular, a coupling to the electromagnetic secto ...

We present the results of the first long-term (2.2 years) spectroscopic monitoring of a gravitationally lensed quasar, namely the Einstein Cross QSO 2237+0305. The goal of this paper is to present the observational facts to be compared in follow-up papers ...

The Euclid space mission will cover over 14 000 deg2 with two optical and near-infrared spectro-photometric instruments, and is expected to detect around ten million active galactic nuclei (AGN). This unique data set will make a considerable impact on our ...

Euclid will provide deep near-infrared (NIR) imaging to ∼26.5 AB magnitude over ∼59 deg2 in its deep and auxiliary fields. The Cosmic DAWN survey combines dedicated and archival UV- NIR observations to provide matched depth multiwavelength imaging of the E ...

This paper presents optical R-band light curves and the time delay of the doubly imaged gravitationally lensed quasar SDSS J1001+5027 at a redshift of 1.838. We have observed this target for more than six years, between March 2005 and July 2011, using the ...

Extragalactic globular clusters (EGCs) are an abundant and powerful tracer of galaxy dynamics and formation, and their own formation and evolution is also a matter of extensive debate. The compact nature of globular clusters means that they are hard to spa ...

We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. 2 per cent level accurate emulation is now supported in the eight-dimensional paramet ...

Core ellipticals, which are massive early-type galaxies with almost constant inner surface brightness profiles, are the result of dry mergers. During these events, a binary black hole (BBH) is formed, destroying the original cuspy central regions of the me ...

Aims. We quantify the intrinsic width of the red giant branches of three massive globular clusters in M31 in a search for metallicity spreads within these objects. ...

We present the results from nine years of optically monitoring the gravitationally lensed z(QSO) = 0.658 quasar RX J1131-1231. The R-band light curves of the four individual images of the quasar were obtained using deconvolution photometry for a total of 7 ...

In this paper we present the framework for measuring angular power spectra in the Euclid mission. The observables in galaxy surveys, such as galaxy clustering and cosmic shear, are not continuous fields, but discrete sets of data, obtained only at the posi ...

We present the results of the first strong lens time delay challenge. The motivation, experimental design, and entry level challenge are described in a companion paper. This paper presents the main challenge, TDC1, which consisted of analyzing thousands of ...

We present a new infrared survey covering the three Euclid deep fields and four other Euclid calibration fields using Spitzer Space Telescope's Infrared Array Camera (IRAC). We combined these new observations with all relevant IRAC archival data of these f ...

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 ...

Intracluster light (ICL) provides a record of the dynamical interactions undergone by clusters, giving clues on cluster formation and evolution. Here, we analyse the properties of ICL in the massive cluster Abell 2390 at redshift z = 0.228. Our analysis is ...

Georges Meylan

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

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

Models of the strongly lensed quasar DES J0408-5354

Euclid: III. The NISP Instrument

COSMOGRAIL XVIII. time delays of the quadruply lensed quasar WFI2033-4723

Euclid: Constraining dark energy coupled to electromagnetism using astrophysical and laboratory data

Microlensing variability in the gravitationally lensed quasar QSO 2237+0305 equivalent to the Einstein Cross - I. Spectrophotometric monitoring with the VLT

Euclid preparation: XLIX. Selecting active galactic nuclei using observed colours

Euclid preparation: LXIV. The Cosmic Dawn Survey (DAWN) of the Euclid Deep and Auxiliary Fields

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XIV. Time delay of the doubly lensed quasar SDSS J1001+5027

Euclid preparation: LVIII. Detecting extragalactic globular clusters in the Euclid survey

Euclid preparation: IX. EuclidEmulator2-power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

Euclid: The rb−M* relation as a function of redshift I. The 5 × 109 M☉ black hole in NGC 1272

Evidence for metallicity spreads in three massive M31 globular clusters

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses XIII. Time delays and 9-yr optical monitoring of the lensed quasar RX J1131-1231

Euclid preparation: LIX. Angular power spectra from discrete observations

Strong Lens Time Delay Challenge. Ii. Results Of Tdc1

Euclid preparation XVII. Cosmic Dawn Survey: Spitzer Space Telescope observations of the Euclid deep fields and calibration fields

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

Euclid: Early Release Observations The intracluster light of Abell 2390