Combining strong and weak lensing estimates in the Cosmos field

TL;DR

This paper combines strong and weak lensing measurements in the COSMOS field to detect their cross-correlation, providing a framework for future systematic checks and small-scale shear power-spectrum analysis.

Contribution

It introduces a novel framework to predict the covariance between strong and weak lensing measurements based on the small scale matter power-spectrum.

Findings

2-sigma detection of the cross-correlation signal

Framework for covariance prediction between lensing probes

Potential for systematic checks with future large samples

Abstract

We present a combined cosmic shear analysis of the modeling of line-of-sight distortions on strongly lensed extended arcs and galaxy shape measurements in the COSMOS field. We develop a framework to predict the covariance of strong lensing and galaxy shape measurements of cosmic shear on the basis of the small scale matter power-spectrum. The weak lensing measurement is performed using data from the COSMOS survey calibrated with a cloning scheme using the Ultra Fast Image Generator UFig (Berge 2013). The strong lensing analysis is performed by forward modeling the lensing arcs with a main lensing deflector and external shear components from the same Hubble Space Telescope imaging data set. With a sample of three strong lensing shear measurements we present a 2-sigma detection of the cross-correlation signal between the two complementary measurements of cosmic shear along the identical line of sight. With large samples of lenses available with the next generation ground and space based observatories, the covariance of the signal of the two probes with large samples of lenses allows for systematic checks, cross-calibration of either of the two measurement and the measurement of the small scale shear power-spectrum.