Moderate Galaxy-Galaxy Lensing

TL;DR

This paper investigates moderate galaxy-galaxy lensing effects, such as isophotal distortions and shifts in galaxy relations, using simulations to understand how these can reveal galaxy mass profiles.

Contribution

It introduces a study of moderate lensing signatures in elliptical galaxies and uses Monte Carlo simulations to explore their potential for probing galaxy mass density slopes.

Findings

Moderate lensing causes measurable isophotal distortions.

Systematic shifts in fundamental plane and Kormendy relation are detectable.

Range of radius probed exceeds that of strong lensing.

Abstract

We study moderate gravitational lensing where a background galaxy is magnified substantially, but not multiply imaged, by an intervening galaxy. We focus on the case where both the lens and source are elliptical galaxies. The signatures of moderate lensing include isophotal distortions and systematic shifts in the fundamental plane and Kormendy relation, which can potentially be used to statistically determine the galaxy mass profiles. These effects are illustrated using Monte Carlo simulations of galaxy pairs where the foreground galaxy is modelled as a singular isothermal sphere model and observational parameters appropriate for the Large Synoptic Survey Telescope (LSST). The range in radius probed by moderate lensing will be larger than that by strong lensing, and is in the interesting regime where the density slope may be changing.