Concept

Dark energy

Related publications (306)

Abell 2744: too much substructure for Lambda CDM?

David Richard Harvey, Mathilde Jauzac, Richard Massey

The massive substructures found in Abell 2744 by Jauzac et al. present a challenge to the cold dark matter paradigm due to their number and proximity to the cluster centre. We use one of the biggest N-body simulations, the Millennium XXL, to investigate th ...

Oxford Univ Press2017

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, Malte Tewes, Vivien François Bonvin

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

A detection of wobbling brightest cluster galaxies within massive galaxy clusters

Jean-Paul Richard Kneib, Frédéric Courbin, David Richard Harvey

A striking signal of dark matter beyond the standard model is the existence of cores in the centre of galaxy clusters. Recent simulations predict that a brightest cluster galaxy ( BCG) inside a cored galaxy cluster will exhibit residual wobbling due to pre ...

Oxford Univ Press2017

The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: tomographic BAO analysis of DR12 combined sample in configuration space

Jean-Paul Richard Kneib, Yuting Wang

We perform a tomographic baryon acoustic oscillations (BAOs) analysis using the two-point galaxy correlation function measured from the combined sample of Baryon Oscillation Spectroscopic Survey Data Release 12 (BOSS DR12), which covers the redshift range ...

Oxford Univ Press2017

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

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: single-probe measurements from CMASS anisotropic galaxy clustering

Jean-Paul Richard Kneib, David Schlegel, Yuting Wang

With the largest spectroscopic galaxy survey volume drawn from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), we can extract cosmological constraints from the measurements of redshift and geometric distortions at quasi-linear scales (e.g. abo ...

Oxford Univ Press2016

The extended Baryon Oscillation Spectroscopic Survey: a cosmological forecast

Jean-Paul Richard Kneib, Johan Comparat, Timothée Guy Olivier Delubac, Yuting Wang, Hanyu Zhang

We present a science forecast for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) survey. Focusing on discrete tracers, we forecast the expected accuracy of the baryonic acoustic oscillation (BAO), the redshift-space distortion (RSD) measureme ...

Oxford Univ Press2016

A 24 mm diameter fibre positioner for spectroscopic surveys

Hannes Bleuler, Jean-Paul Richard Kneib, Mohamed Bouri, Luzius Gregor Kronig, Philipp Hörler

One of the big research topics in modern cosmology is the mystery of dark Energy. To unveil the secret, cosmologists want to measure precisely the evolution of large scale structures in the universe. One way of doing so is to measure the 3D location of a h ...

Spie-Int Soc Optical Engineering2016

Time-sliced perturbation theory II: baryon acoustic oscillations and infrared resummation

Sergey Sibiryakov, Diego Blas Temino, Mikhail Ivanov

We use time-sliced perturbation theory (TSPT) to give an accurate description of the infrared non-linear effects affecting the baryonic acoustic oscillations (BAO) present in the distribution of matter at very large scales. In TSPT this can be done via a s ...

Iop Publishing Ltd2016

The DESI fiber positioner system

Jean-Paul Richard Kneib, Philipp Hörler

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the baryon acoustic oscillation technique. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5,000 fi ...

Spie-Int Soc Optical Engineering2016

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