Delayed Formation of Bulges by Dynamical Processes
Abstract
Two mechanisms involving purely dynamical processes can lead to the formation of a bulge after its disc: 1) small bulges (1-2 kpc), including box-shaped bulges and mildly triaxial bulges, can result from the formation and destruction of a bar; 2) big bulges (>2 kpc) a la Sombrero can grow following the accretion of small satellites. Fully consistent N-body simulations show that the fraction of galaxy mass accreted in this way needs to be larger than about 5%. Less accretion does not create smaller bulges, but heats the whole disc. These dynamical effects transforming Hubble types from SB to SA and vice-versa over ~ 1-2 Gyr also indicate, by the secular growth of bulges, a general sense of galactic evolution from Sd to Sa.
- Publication:
-
Galactic Bulges
- Pub Date:
- 1993
- Bibcode:
- 1993gabu.symp..387P
- Keywords:
-
- BULGE FORMATION;
- GALAXY EVOLUTION;
- N-BODY SIMULATION