Publications associées à MASS-CONCENTRATION RELATION OF CLUSTERS OF GALAXIES FROM CFHTLenS

Euclid: Validation of the MontePython forecasting tools

Slobodan Ilic, Georges Meylan, Frédéric Courbin, Julien Lesgourgues, Richard Massey, Maurizio Martinelli, Jean-Luc Starck, Yi Wang

Context. The Euclid mission of the European Space Agency will perform a survey of weak lensing cosmic shear and galaxy clustering in order to constrain cosmological models and fundamental physics. Aims. We expand and adjust the mock Euclid likelihoods of t ...

Edp Sciences S A2024

CURLING - I. The influence of point-like image approximation on the outcomes of cluster strong lens modelling

Nan Li, Jean-Paul Richard Kneib, Huanyuan Shan

Cluster-scale strong lensing is a powerful tool for exploring the properties of dark matter and constraining cosmological models. However, due to the complex parameter space, pixelized strong lens modelling in galaxy clusters is computationally expensive, ...

Oxford Univ Press2024

Strong gravitational lensing's 'external shear' is not shear

Richard Massey, David Richard Harvey, Mathilde Jauzac

The distribution of mass in galaxy-scale strong gravitational lenses is often modelled as an elliptical power-law plus 'external shear', which notionally accounts for neighbouring galaxies and cosmic shear along our line of sight. A small amount of externa ...

Oxford Univ Press2024

XXXIV. The effect of linear redshift-space distortions in photometric galaxy clustering and its cross-correlation with cosmic shear

Slobodan Ilic, Malte Tewes, Georges Meylan, Frédéric Courbin, Fabio Finelli, Richard Massey, Maurizio Martinelli, Alessandro Pezzotta, Gianluca Castignani, Marcello Farina, Yi Wang

Context. The cosmological surveys that are planned for the current decade will provide us with unparalleled observations of the distribution of galaxies on cosmic scales, by means of which we can probe the underlying large-scale structure (LSS) of the Univ ...

Edp Sciences S A2024

Time-Delay Cosmography: Measuring the Hubble Constant and Other Cosmological Parameters with Strong Gravitational Lensing

Frédéric Courbin, Martin Raoul Robert Millon

Multiply lensed images of a same source experience a relative time delay in the arrival of photons due to the path length difference and the different gravitational potentials the photons travel through. This effect can be used to measure absolute distance ...

Springer2024

Hydrodynamical simulations of merging galaxy clusters: giant dark matter particle colliders, powered by gravity

Richard Massey, David Richard Harvey

Terrestrial particle accelerators collide charged particles, then watch the trajectory of outgoing debris - but they cannot manipulate dark matter. Fortunately, dark matter is the main component of galaxy clusters, which are continuously pulled together by ...

Oxford Univ Press2024

Euclid: The search for primordial features

Georges Meylan, Frédéric Courbin, Fabio Finelli, Richard Massey, Marcello Farina, Yiming Li, Yi Wang

Primordial features, in particular oscillatory signals, imprinted in the primordial power spectrum of density perturbations represent a clear window of opportunity for detecting new physics at high-energy scales. Future spectroscopic and photometric measur ...

Edp Sciences S A2024

The Origins of Gas Accreted by Supermassive Black Holes: The Importance of Recycled Gas

Michaela Hirschmann

We investigate the fueling mechanisms of supermassive black holes (SMBHs) by analyzing 10 zoom-in cosmological simulations of massive galaxies, with stellar masses 1011-12 M circle dot and SMBH masses 108.9-9.7 M circle dot at z = 0, featuring various majo ...

Iop Publishing Ltd2024

Euclid: Improving the efficiency of weak lensing shear bias calibration

Malte Tewes, Georges Meylan, Frédéric Courbin, Richard Massey, Marcello Farina, Yi Wang

To obtain an accurate cosmological inference from upcoming weak lensing surveys such as the one conducted by Euclid, the shear measurement requires calibration using galaxy image simulations. As it typically requires millions of simulated galaxy images and ...

Edp Sciences S A2024

Validation of the Scientific Program for the Dark Energy Spectroscopic Instrument

Eduardo Sanchez, Zhifeng Ding, Sun Hee Kim, Hua Zhang, Stewart Cole, Jiangyan Yang, Jean-Paul Richard Kneib, Anand Stéphane Raichoor, Andrei Variu, Ting Tan, Daniel Felipe Forero Sanchez, Cheng Zhao, Arjun Dey, David Schlegel, Zheng Zheng, Xin Chen

The Dark Energy Spectroscopic Instrument (DESI) was designed to conduct a survey covering 14,000 deg(2) over 5 yr to constrain the cosmic expansion history through precise measurements of baryon acoustic oscillations (BAO). The scientific program for DESI ...

Iop Publishing Ltd2024

Gibbs sampling the posterior of neural networks

Giovanni Piccioli, Lenka Zdeborová, Emanuele Troiani

In this paper, we study sampling from a posterior derived from a neural network. We propose a new probabilistic model consisting of adding noise at every pre- and post-activation in the network, arguing that the resulting posterior can be sampled using an ...

Iop Publishing Ltd2024

Weak gravitational lensing measurements of Abell 2744 using JWST and shear measurement algorithm pyRRG-JWST

Richard Massey, David Richard Harvey

We update the publicly available weak lensing shear measurement algorithm pyRRG for the JWST, and apply it to UNCOVER DR1 imaging of galaxy cluster Abell 2744. At short wavelengths (

Oxford Univ Press2024

Small-amplitude Red Giants Elucidate the Nature of the Tip of the Red Giant Branch as a Standard Candle

Richard Irving Anderson, Nolan Wayne Koblischke

The tip of the red giant branch (TRGB) is an important standard candle for determining luminosity distances. Although several 105 small-amplitude red giant stars (SARGs) have been discovered, variability was previously considered irrelevant for the TRGB as ...

Iop Publishing Ltd2024

Live-cell imaging powered by computation

Suliana Manley, Florian Jug

The proliferation of microscopy methods for live-cell imaging offers many new possibilities for users but can also be challenging to navigate. The prevailing challenge in live-cell fluorescence microscopy is capturing intra-cellular dynamics while preservi ...

Nature Portfolio2024

The phase-space distribution of the M 81 satellite system

Oliver Müller, Nick Heesters

The spatial distribution of dwarf galaxies around their host galaxies is a critical test for the standard model of cosmology because it probes the dynamics of dark matter halos and is independent of the internal baryonic processes of galaxies. Comoving pla ...

Edp Sciences S A2024

Spectral Estimators for High-Dimensional Matrix Inference

Farzad Pourkamali

A key challenge across many disciplines is to extract meaningful information from data which is often obscured by noise. These datasets are typically represented as large matrices. Given the current trend of ever-increasing data volumes, with datasets grow ...

EPFL2024

Euclid preparation XXXVI. Modelling the weak lensing angular power spectrum

Georges Meylan, Frédéric Courbin, Fabio Finelli, Richard Massey, Maurizio Martinelli, Gianluca Castignani, Marcello Farina, Austin Chandler Peel, Yi Wang

This work considers which higher order modeling e ffects on the cosmic shear angular power spectra must be taken into account for Euclid. We identified the relevant terms and quantified their individual and cumulative impact on the cosmological parameter i ...

Edp Sciences S A2024

Euclid preparation XXXVII. Galaxy colour selections with Euclid and ground photometry for cluster weak-lensing analyses

Matthias Wiesmann, Georges Meylan, Frédéric Courbin, Fabio Finelli, Richard Massey, Maurizio Martinelli, Gianluca Castignani, Marcello Farina, Yi Wang

Aims. We derived galaxy colour selections from Euclid and ground-based photometry, aiming to accurately define background galaxy samples in cluster weak-lensing analyses. These selections have been implemented in the Euclid data analysis pipelines for gala ...

Edp Sciences S A2024

Searching for Strong Gravitational Lenses

Frédéric Courbin, Cameron Alexander Campbell Lemon

Strong gravitational lenses provide unique laboratories for cosmological and astrophysical investigations, but they must first be discovered - a task that can be met with significant contamination by other astrophysical objects and asterisms. Here we revie ...

Springer2024

A continuous-wave and pulsed X-band electron spin resonance spectrometer operating in ultra-high vacuum for the study of low dimensional spin ensembles

Giovanni Boero, Fabio Donati, Soyoung Oh

We report the development of a continuous-wave and pulsed X-band electron spin resonance (ESR) spectrometer for the study of spins on ordered surfaces down to cryogenic temperatures. The spectrometer operates in ultra-high vacuum and utilizes a half-wavele ...

Aip Publishing2024