On the nature of bulges in general and of box/peanut bulges in particular: input from N-body simulations
Abstract
Objects designated as bulges in disc galaxies do not form a homogeneous class. I distinguish three types: the classical bulges, the properties of which are similar to those of ellipticals and which form by collapse or merging; boxy and peanut bulges, which are seen in near-edge-on galaxies and which are in fact just a part of the bar seen edge-on; and, finally, disc-like bulges, which result from the inflow of (mainly) gas to the centre-most parts, and subsequent star formation. I make a detailed comparison of the properties of boxy and peanut bulges with those of N-body bars seen edge-on, and answer previously voiced objections about the links between the two. I also present and analyse simulations where a boxy/peanut feature is present at the same time as a classical spheroidal bulge, and compare them with observations. Finally, I propose a nomenclature that can help to distinguish between the three types of bulges and avoid considerable confusion.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2005
- DOI:
- 10.1111/j.1365-2966.2005.08872.x
- arXiv:
- arXiv:astro-ph/0502316
- Bibcode:
- 2005MNRAS.358.1477A
- Keywords:
-
- methods: N-body simulations;
- galaxies: bulges;
- galaxies: evolution;
- galaxies: kinematics and dynamics;
- galaxies: photometry;
- galaxies: structure;
- Astrophysics
- E-Print:
- 13 pages, 7 figures, accepted for publication in MNRAS