The Diffuse Light Envelope of Luminous Red Galaxies

TL;DR

This study uses stacking to analyze the extended light profiles of luminous red galaxies at two different redshifts, revealing a consistent profile shape with a small excess light component beyond 60 kpc.

Contribution

It provides the first detailed measurement of the diffuse light envelope of LRGs out to 200 kpc at two redshifts, showing profile stability over time.

Findings

LRG profiles are well fitted by a single Sersic profile.

Excess light beyond 60 kpc accounts for about 10% of total flux.

No significant evolution in LRG profiles between the two redshifts.

Abstract

We use a stacking method to study the radial light profiles of luminous red galaxies (LRGs) at redshift $\sim 0.62$ and $\sim 0.25$, out to a radial range of 200 kpc. We do not find noticeable evolution of the profiles at the two redshifts. The LRG profiles appear to be well approximated by a single Sersic profile, although some excess light can be seen outside 60 kpc. We quantify the excess light by measuring the integrated flux and find that the excess is about 10\% -- a non-dominant but still nonnegligible component.