Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-08-13
Astrophys.J. 613 (2004) L29-L32
Astronomy and Astrophysics
Astrophysics
7 pages, 4 figures, ApJ Letters, in press
Scientific paper
10.1086/424876
Young stellar bars in disk galaxies experience a vertical buckling instability which terminates their growth and thickens them, resulting in a characteristic peanut/boxy shape when viewed edge on. Using N-body simulations of galactic disks embedded in live halos, we have analyzed the bar structure throughout this instability and found that the outer third of the bar dissolves completely while the inner part (within the vertical inner Lindblad resonance) becomes less oval. The bar acquires the frequently observed peanut/boxy-shaped isophotes. We also find that the bar buckling is responsible for a mass injection above the plane, which is subsequently trapped by specific 3-D families of periodic orbits of particular shapes explaining the observed isophotes, in line with previous work. Using a 3-D orbit analysis and surfaces of sections, we infer that the outer part of the bar is dissolved by a rapidly widening stochastic region around its corotation radius -- a process related to the bar growth. This leads to a dramatic decrease in the bar size, decrease in the overall bar strength and a mild increase in its pattern speed, but is not expected to lead to a complete bar dissolution. The buckling instability appears primarily responsible for shortening the secular diffusion timescale to a dynamical one when building the boxy isophotes. The sufficiently long timescale of described evolution, ~1 Gyr, can affect the observed bar fraction in local universe and at higher redshifts, both through reduced bar strength and the absence of dust offset lanes in the bar.
Martinez-Valpuesta Inma
Shlosman Isaac
No associations
LandOfFree
Why Buckling Stellar Bars Weaken in Disk Galaxies 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 Why Buckling Stellar Bars Weaken in Disk Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Why Buckling Stellar Bars Weaken in Disk Galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-200277