Theoretical Estimates of 2-point Shear Correlation Functions Using Tangled Magnetic Field Power Spectrum

TL;DR

This paper provides theoretical estimates of how primordial magnetic fields influence the two-point shear correlation function in gravitational lensing, offering constraints on magnetic field parameters and prospects for future detection.

Contribution

It introduces a theoretical framework linking tangled magnetic field spectra to shear correlation functions and derives constraints from observational data.

Findings

Primordial magnetic fields affect shear correlation at small angular scales.

CFHTLS data constrains magnetic field strength and spectral index.

Future missions could detect sub-nano Gauss magnetic fields.

Abstract

The existence of primordial magnetic fields can induce matter perturbations with additional power at small scales as compared to the usual $\Lambda$CDM model. We study its implication within the context of two-point shear correlation function from gravitational lensing. We show that primordial magnetic field can leave its imprints on the shear correlation function at angular scales $\lesssim \hbox{a few arcmin}$. The results are compared with CFHTLS data, which yields some of the strongest known constraints on the parameters (strength and spectral index) of the primordial magnetic field. We also discuss the possibility of detecting sub-nano Gauss fields using future missions such as SNAP.