Three-dimensional decomposition of galaxies with bulge and long bar

¹ Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife Spain
e-mail: paulc@iac.es
² Universidad de La Laguna, Dpto. Astrofísica, 38206, La Laguna, Tenerife, Spain

Received: 9 July 2014
Accepted: 13 October 2014

Abstract

Context. Some observations indicate that the Milky Way has two inner components, a bulge and a long bar, which present a misalignment of Δα ≃ 20° that is against the predictions of some theoretical models that are based on numerical simulations.

Aims. We wish to determine whether this misalignment between the bar and the bulge can be observed in barred galaxies other than the Milky Way.

Methods. Each galaxy of our sample was decomposed based on its K_s-band 2MASS image by fitting and modelling in a three-dimensional (3D) space the following components: a disc, a bar, and a bulge. The χ² goodness-of-fit estimation allowed retrieving the best-fit angle values for the bar and the bulge to detect any misalignment.

Results. 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 Δα> 20°.