Boxy/peanut/X bulges, barlenses and the thick part of galactic bars: What are they and how did they form?

Abstract

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 viewed face-on it is referred to as a barlens. These components are due to disc and bar instabilities and are composed of disc material. I review here their formation, evolution and dynamics, using simulations, orbital structure theory and comparisons to observations.

21 pages, 7 figures, invited review to appear in "Galactic Bulges", E. Laurikainen, R. Peletier, D. Gadotti, (eds.), Springer

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Cited by in corpus (30)

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• Barlenses and X-shape features compared: different manifestations of Boxy/Peanut bulges
• The Bar and Spiral Arms in the Milky Way: Structure and Kinematics
• Quantifying the (X/Peanut)-Shaped Structure in Edge-on Disc Galaxies: Length, Strength, and Nested Peanuts
• Structural and photometric properties of barred galaxies from the Auriga cosmological simulations
• Quantifying the (X/peanut)-shaped Structure of the Milky Way - New Constraints on the Bar Geometry
• Tidally induced bars in dwarf galaxies on different orbits around a Milky Way-like host
• Boxy/Peanut/X-shape bulges: steep inner rotation curve leads to barlens face-on morphology
• Orbital classification in an N-body bar
• The Effect of Dark Matter Halo Shape on Bar Buckling and Boxy/Peanut Bulges
• Face-on structure of barlenses and boxy bars: an insight from spectral dynamics
• The origin of the LMC stellar bar: clues from the SFH of the bar and inner disk
• Tidally induced bars in gas-rich dwarf galaxies orbiting the Milky Way
• Origin of Non-axisymmetric Features of Virgo Cluster Early-type Dwarf Galaxies. I. Bar Formation and Recurrent Buckling
• Building the peanut: simulations and observations of peanut-shaped structures and ansae in face-on disk galaxies
• Buckling bars in nearly face-on galaxies observed with MaNGA
• Galactic Orbits of Globular Clusters in the Region of the Galactic Bulge
• IllustrisTNG Insights: Factors Affecting the Presence of Bars in Disk Galaxies
• Bars and boxy/peanut bulges in thin and thick discs III. Boxy/peanut bulge formation and evolution in presence of thick discs
• Double X/Peanut Structures in Barred Galaxies -- Insights from an $N$--body Simulation
• Unravelling stellar populations in the Andromeda Galaxy
• Growth of disc-like pseudo-bulges in SDSS DR7 since z = 0.1
• First direct identification of the barlens vertical structure in galaxy models
• The diverse physical origins of stars in the dynamically hot bulge: CALIFA vs. IllustrisTNG
• NGC 7457: Evidence for merger-driven cylindrical rotation in disc galaxies
• Orbit evolution in growing stellar bars: Bar-supporting orbits at the vertical ILR region
• Asteroseismology of red giants & galactic archaeology