2D Surface Brightness Modelling of Large 2MASS Galaxies I: Photometry and Structural Parameters

TL;DR

This study performs detailed 2D surface brightness photometric decomposition of 101 nearby 2MASS galaxies across three bands, deriving structural parameters and distinguishing bulge types, confirming known trends and providing new insights into galaxy morphology.

Contribution

It offers a comprehensive multi-component photometric analysis of large nearby galaxies, including a novel classification of bulges and comparison of photometric data sources.

Findings

Early-type galaxy magnitudes are ~0.35 mag dimmer in LGA mosaics.

Approximately 40% of galaxies host pseudobulges, mainly in late-type galaxies.

Results confirm known trends in Sersic index, B/T, and q ratios.

Abstract

We have studied a sample of 101 bright 2MASS galaxies from the Large Galaxy Atlas (LGA), whose morphologies span from early to late-types. We have generated estimates for structural parameters through a two-dimensional (2D) surface brightness photometric decomposition in the three 2MASS bands (J, H, Ks). This work represents a detailed multi-component photometric study of nearby galaxies. We report total magnitudes, effective radii, concentration indices, among other parameters, in the three 2MASS bands. We found that the integrated total magnitudes of early-type galaxies (ETGs) measured on 2MASS LGA mosaics are ~0.35 mag dimmer, when compared with images generated from IRSA image tiles service; nevertheless, when comparing late-type galaxies (LTGs) we did not find any difference. Therefore, for ETGs we present the results derived on IRSA image tiles, while for LTGs we used data from the LGA mosaics. Additionally, by combining these structural parameters with scaling relations and kinematic data, we separated classical bulges from pseudobulges. We found that ~40 % of the objects in our sample are classified as pseudobulges, which are found preferentially in LTGs. Also, our findings confirm trends reported earlier in the distributions for some physical parameters, such as S\'ersic index, B/T and q ratios. In general, our results are in agreement with previous one-dimensional studies. In a companion paper, we revise some of the scaling relations among global galaxy properties, as well as their interrelation with Supermassive Black Holes.