GEPI

A large proportion of barred galaxies are known to display characteristic boxy/peanut (B/P in short) or X-shaped stellar structures observed in close to edge-on orientation of the disc. These features, sometimes referred to as B/P ’bulges’, arise as a consequence of secular processes whereby the bar becomes vertically unstable and ’buckles’ outside of the plane of the disc. In this seminar I will discuss ways to quantitatively characterise these stellar structures, and what insight we have gained from nearby galaxy observations and N-body simulations, with a focus on peculiar systems where the B/P feature appears twice in the same galaxy, at different radii. Finally I will discuss how our own Galaxy fits into this picture, with hopes that Gaia data might soon deepen our understanding of the Milky Way’s B/P bulge, and bar.