2D kinematic signatures of boxy/peanut bulges

TL;DR

This study investigates how boxy/peanut bulges in disk galaxies influence 2D kinematic signatures, aiding in their identification through IFU observations, by analyzing simulated models with varying structural parameters.

Contribution

It extends previous work to 2D kinematic analysis, exploring effects of bulge strength, buckling, and inclination on observable kinematic features in simulated galaxies.

Findings

Strong boxy/peanut structures show characteristic kinematic features away from the midplane.

Second buckling induces deeper minima in the fourth Gauss-Hermite moment.

Inclination affects the visibility of kinematic signatures of bulges.

Abstract

We study the imprints of boxy/peanut structures on the 2D line-of-sight kinematics of simulated disk galaxies. The models under study belong to a family with varying initial gas fraction and halo triaxiality, plus few other control runs with different structural parameters; the kinematic information was extracted using the Voronoi-binning technique and parametrised up to the fourth order of a Gauss-Hermite series. Building on a previous work for the long-slit case, we investigate the 2D kinematic behaviour in the edge-on projection as a function of the boxy/peanut strength and position angle; we find that for the strongest structures the highest moments show characteristic features away from the midplane in a range of position angles. We also discuss the masking effect of a classical bulge and the ambiguity in discriminating kinematically this spherically-symmetric component from a boxy/peanut bulge seen end-on. Regarding the face-on case, we extend existing results to encompass the effect of a second buckling and find that this phenomenon spurs an additional set of even deeper minima in the fourth moment. Finally, we show how the results evolve when inclining the disk away from perfectly edge-on and face-on. The behaviour of stars born during the course of the simulations is discussed and confronted to that of the pre-existing disk. The general aim of our study is providing a handle to identify boxy/peanut structure and their properties in latest generation IFU observations of nearby disk galaxies.