Maximum likelihood method for fitting the Fundamental Plane of the 6dF Galaxy Survey

TL;DR

This paper introduces a maximum likelihood method to accurately fit the Fundamental Plane of early-type galaxies using the 6dF Galaxy Survey, accounting for observational biases and revealing dependencies on stellar populations and environment.

Contribution

The paper presents a novel maximum likelihood fitting technique for the Fundamental Plane that effectively handles selection effects and observational errors, improving parameter estimation.

Findings

Accurate Fundamental Plane parameters derived from over 10,000 galaxies.

Method accounts for selection effects, censoring, and errors.

Reveals dependencies of the Fundamental Plane on stellar populations and environment.

Abstract

We have used over 10,000 early-type galaxies from the 6dF Galaxy Survey (6dFGS) to construct the Fundamental Plane across the optical and near-infrared passbands. We demonstrate that a maximum likelihood fit to a multivariate Gaussian model for the distribution of galaxies in size, surface brightness and velocity dispersion can properly account for selection effects, censoring and observational errors, leading to precise and unbiased parameters for the Fundamental Plane and its intrinsic scatter. This method allows an accurate and robust determination of the dependencies of the Fundamental Plane on variations in the stellar populations and environment of early-type galaxies.