Three-dimensional decomposition of galaxies with bulge and long bar

TL;DR

This study uses 3D decomposition of galaxy images to detect misalignments between bulge and bar components, revealing that at least three out of six studied galaxies exhibit significant misalignments similar to the Milky Way.

Contribution

It introduces a 3D decomposition method to analyze bulge and bar orientations in external galaxies, extending Milky Way findings to other barred galaxies.

Findings

Detected significant bulge-bar misalignments in three galaxies.

Confirmed that misalignments greater than 20 degrees are observable.

Demonstrated the effectiveness of 3D decomposition in galaxy structure analysis.

Abstract

Some observations indicate that the Milky Way has two inner components, a bulge and a long bar, which present a misalignment of about 20 degrees that is against the predictions of some theoretical models that are based on numerical simulations. In this paper, we wish to determine whether this misalignment between the bar and the bulge can be observed in barred galaxies other than the Milky Way. For that, each galaxy of our sample was decomposed based on its Ks-band 2MASS image by fitting and modelling in a three-dimensional (3D) space the following components: a disc, a bar, and a bulge. The chi-square goodness-of-fit estimation allowed retrieving the best-fit angle values for the bar and the bulge to detect any misalignment. From the 3D decomposition of six barred galaxies, we have detected at least three galaxies (NGC 2217, NGC 3992, and NGC 4593) that present a significant misalignment between the bar and the bulge of more than 20 degrees.