Astronomy and Astrophysics – Astrophysics
Scientific paper
Sep 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993a%26a...277...27f&link_type=abstract
Astronomy and Astrophysics, Vol. 277, NO. 1/SEP(III), P. 27, 1993
Astronomy and Astrophysics
Astrophysics
231
Scientific paper
We review observations of spiral or lenticular barred galaxies having inside their primary bar either a misaligned inner (secondary) bar or a misaligned triaxial bulge. Some CCD near-IR images are presented. Galaxies with a nuclear ring, as well as our Galaxy, are considered as other likely candidates for having bars within bars. Some cases cannot be explained in terms of projection effects on two perpendicular bars. No favoured angle between the two stellar bars is found. The secondary bar either leads or trails the primary bar, strongly indicating time- dependent systems rotating with two different pattern speeds. Offsets between a stellar bar and a gaseous bar can be explained with identical pattern speeds under particular conditions. Models of embedded or nested bars, produced by self-consistent 3D N-body simulations with gas and stars, are presented and the necessary and specific conditions for them to be formed are given. Dissipation as well as a moderate inner Lindblad resonance play a major role to induce and maintain the decoupling between the central and outer galaxy parts. The double-barred systems are stable over more than 5 turns of the secondary bar which is also the faster one. In some cases, a nuclear gaseous ring is formed near the secondary bar end. The system of embedded bars transports amounts of gas closer to the galactic center and may be invoked as a likely mechanism to fuel active galactic nuclei. The two bar phase is followed by the dissolution of the secondary bar or even the two bars (depending on the model) which is induced by a broad and strong inner Lindblad resonance. The final central galaxy shape resulting from the two bar destruction is similar to observed triaxial bulges, suggesting that some of them are relics of destroyed bars. Thus, disc galaxies can be viewed as time-dependent systems, where secular evolution, especially due to dissipative effects, is strongly transforming their morphologies and their kinematics over less than a Hubble time. Secular evolution causes galaxies to change their Hubble type during their lifetimes.
Friedli Daniel
Martinet Louis
No associations
LandOfFree
Bars Within Bars in Lenticular and Spiral Galaxies - a Step in Secular Evolution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Bars Within Bars in Lenticular and Spiral Galaxies - a Step in Secular Evolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bars Within Bars in Lenticular and Spiral Galaxies - a Step in Secular Evolution will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1558920