First measurement of the cross-correlation of CMB lensing and galaxy lensing

Jean-Paul Richard Kneib, Huanyuan Shan
2015
Journal paper

Abstract

We measure the cross-correlation of cosmic microwave background (CMB) lensing convergence maps derived from Atacama Cosmology Telescope data with galaxy lensing convergence maps as measured by the Canada-France-Hawaii Telescope Stripe 82 Survey. The CMB-galaxy lensing cross power spectrum is measured for the first time with a significance of 4.2 sigma, which corresponds to a 12% constraint on the amplitude of density fluctuations at redshifts similar to 0.9. With upcoming improved lensing data, this novel type of measurement will become a powerful cosmological probe, providing a precise measurement of the mass distribution at intermediate redshifts and serving as a calibrator for systematic biases in weak lensing measurements.

Official source

https://infoscience.epfl.ch/record/207303?ln=en

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Ontological neighbourhood

Astronomy

Astrophysics: Physical cosmology

Related concepts (32)

While the presence of any mass bends the path of light passing near it, this effect rarely produces the giant arcs and multiple images associated with strong gravitational lensing. Most lines of sight in the universe are thoroughly in the weak lensing regime, in which the deflection is impossible to detect in a single background source. However, even in these cases, the presence of the foreground mass can be detected, by way of a systematic alignment of background sources around the lensing mass.

A gravitational lens is a distribution of matter (such as a cluster of galaxies) or a point particle between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity. Treating light as corpuscles travelling at the speed of light, Newtonian physics also predicts the bending of light, but only half of that predicted by general relativity.

The cosmic microwave background (CMB, CMBR) is microwave radiation that fills all space in the observable universe. It is a remnant that provides an important source of data on the primordial universe. With a standard optical telescope, the background space between stars and galaxies is almost completely dark. However, a sufficiently sensitive radio telescope detects a faint background glow that is almost uniform and is not associated with any star, galaxy, or other object.

Related publications (32)

Related MOOCs (5)

This course covers the principles and practices of radio astronomical observations, in particular with modern interferometers. Topics range from radio telescope technology to the measurement equation

Be captivated by the exotic objects that populate the Radio Sky and gain a solid understanding of their physics and the fundamental techniques we use to observe them.

Ce cours décrit les principaux concepts physiques utilisés en astrophysique. Il est proposé à l'EPFL aux étudiants de 2eme année de Bachelor en physique.

First measurement of the cross-correlation of CMB lensing and galaxy lensing

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

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