Shape, Color and Distance in Weak Gravitational Flexion

TL;DR

This study investigates the impact of galaxy morphology on gravitational flexion measurements, finding that early-type galaxies exhibit lower intrinsic flexion noise, which can be reduced significantly, improving flexion analysis accuracy.

Contribution

The paper introduces a new analysis of galaxy flexion signals using the Lenser code and demonstrates the correlation between galaxy type and flexion noise reduction.

Findings

Early-type galaxies have lower flexion noise than late-type galaxies.

Flexion noise can be reduced by more than a factor of two.

Morphological characteristics influence flexion measurement precision.

Abstract

Canonically, elliptical galaxies might be expected to have a perfect rotational symmetry, making them ideal targets for flexion studies - however, this assumption hasn't been tested. We have undertaken an analysis of low and high redshift galaxy catalogs of known morphological type with a new gravitational lensing code, Lenser. Using color measurements in the u-r band and fit Sersic index values, objects with characteristics consistent with early-type galaxies are found to have a lower intrinsic scatter in flexion signal than late-type galaxies. We find this measured flexion noise can be reduced by more than a factor of two at both low and high redshift.