2D surface brightness modelling of large 2MASS galaxies – I: photometry and structural parameters

Abstract

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 surface brightness photometric decomposition in the three 2MASS bands (J, H, and Ks). This work represents a detailed multicomponent photometric study of nearby galaxies. We report total magnitudes, effective radii, and 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 tile 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 pseudo-bulges. We found that ${\sim} 40{{\ \rm per\ cent}}$ of the objects in our sample are classified as pseudo-bulges, which are found preferentially in LTGs. Also, our findings confirm trends reported earlier in the distributions for some physical parameters, such as Sérsic index and 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.