Related papers: Boxy/peanut bulges : formation, evolution and prop…
The class `bulges' contains objects with very different formation and evolution paths and very different properties. I review two types of `bulges', the boxy/peanut bulges (B/Ps) and the discy bulges. The former are parts of bars seen…
Boxy/peanut (b/p) bulges, the vertically extended inner parts of bars, are ubiquitous in barred galaxies in the local Universe, including our own Milky Way. At the same time, a majority of external galaxies and the Milky Way also possess a…
We present a systematic observational study of the relationship between bars and boxy/peanut-shaped (B/PS) bulges. We first review and discuss proposed mechanisms for their formation, focussing on accretion and bar-buckling scenarios. Using…
Prompted by work on the buckling instability in barred spiral galaxies, much effort has been devoted lately to the study of boxy/peanut-shaped (B/PS) bulges. Here, we present new bar diagnostics for edge-on spiral galaxies based on periodic…
Vertically thickened bars, observed in the form of boxy/peanut (B/P) bulges, are found in the majority of massive barred disc galaxies in the local Universe, including our own. B/P bulges indicate that their host bars have suffered violent…
Boxy/peanut (b/p) or X-shaped bulges have been extensively explored with theory and numerical simulations of isolated galaxies. However, it is only recently that advances in hydrodynamical cosmological simulations have made it possible to…
We review the observed morphological, photometric, and kinematic properties of boxy/peanut (B/P) shape bulges. Nearly half of the bulges in the nearby edge-on galaxies have these characteristics, which fraction is similar to the observed…
I discuss several aspects of secular evolution linked to bars and to boxy/peanut bulges, based on a very large number of high resolution, fully self-consistent $N$-body simulations. When the bar forms, it is as thin as the disc. Its…
Boxy, peanut- or X-shaped "bulges" are observed in a large fraction of barred galaxies viewed in, or close to, edge-on projection, as well as in the Milky Way. They are the product of dynamical instabilities occurring in stellar bars, which…
Bars have a complex three-dimensional shape. In particular their inner part is vertically much thicker than the parts further out. Viewed edge-on, the thick part of the bar is what is commonly known as a boxy-, peanut- or X- bulge and…
Boxy/peanut bulges in disk galaxies have been associated to stellar bars. In this talk, we discuss the different properties of such bulges and their relation with the corresponding bar, using a very large sample of a few hundred numerical…
It is well established that bars evolve significantly after they form in galaxy discs, often changing shape both in and out of the disc plane. In some cases they may bend or buckle out of the disc plane resulting in the formation of…
Boxy/peanut and X-shaped (BP/X) bulges are prominent features in edge-on disk galaxies and are believed to be vertically thickened bars. Despite their relevance in bar evolution, a statistically robust census of these structures in large…
We investigate whether the formation mechanism of boxy and peanut-shaped (B/PS) bulges could depend on the gas content of the galaxy. We have performed N-body simulations with and without a gaseous component. In the second case star…
Boxy/peanut bulges in disc galaxies have been associated to stellar bars. We analyse their properties in a large sample of $N$-body simulations, using different methods to measure their strength, shape and possible asymmetry, and then…
Angular momentum redistribution within barred galaxies drives their dynamical evolution. Angular momentum is emitted mainly by near-resonant material in the bar region and absorbed by resonant material mainly in the outer disc and in the…
The short-lived buckling instability is responsible for the formation of at least some box/peanut (B/P) shaped bulges, which are observed in most massive, $z=0$, barred galaxies. Nevertheless, it has also been suggested that B/P bulges form…
The majority of massive disk galaxies, including our own, have stellar bars with vertically thick inner regions -- so-called "boxy/peanut-shaped" (B/P) bulges. The most commonly suggested mechanism for the formation of B/P bulges is a…
It has been suggested that the peanut-shaped bulges seen in some edge-on disk galaxies are produced when bars in these galaxies buckle. This paper reviews the modelling which seeks to show how bars buckle, and I present a very simple new…
We examine the effects that the modelling of a Boxy/Peanut (B/P) bulge will have on the estimates of the stellar gravitational potential, forces, orbital structure and bar strength of barred galaxies. We present a method for obtaining the…