Near-infrared and optical broadband surface photometry of 86 face-on disk dominated galaxies. II. A two-dimensional method to determine bulge and disk parameters

TL;DR

This paper introduces a new two-dimensional galaxy decomposition method using exponential profiles for bulge and disk, tested for accuracy and compared with traditional one-dimensional techniques, demonstrating improved reliability in parameter estimation.

Contribution

The paper presents a novel 2D decomposition technique that models galaxy surface photometry with exponential profiles, offering more accurate bulge and disk parameters than existing 1D methods.

Findings

2D decomposition yields more reproducible parameters.

Maximum errors in parameters are about 20%.

Method performs well across optical and near-infrared data.

Abstract

In this paper I present a new two-dimensional decomposition technique, which models the surface photometry of a galaxy with an exponential light profile for both bulge and disk and, when necessary, with a Freeman bar. The new technique was tested for systematic errors on both artificial and real data and compared with widely used one-dimensional decomposition techniques, where the luminosity profile of the galaxy is used. The comparisons indicate that a decomposition of the two-dimensional image of the galaxy with an exponential light profile for both bulge and disk yields the most reproducible and representative bulge and disk parameters. An extensive error analysis was made to determine the reliability of the model parameters. If the model with an exponential bulge profile is a reasonable description of a galaxy, the maximum errors in the derived model parameters are of order 20%. The uncertainties in the model parameters will increase, if the exponential bulge function is replaced by other often used bulge functions as the de Vaucouleurs law. All decomposition methods were applied to the optical and near-infrared data set presented by de Jong & van der Kruit (1994), which comprises 86 galaxies in six passbands.