Astronomy and Astrophysics – Astrophysics
Scientific paper
2003-01-13
Astrophys.J. 590 (2003) 619-635
Astronomy and Astrophysics
Astrophysics
17 pages, 20 color figures, replaced with published version ApJ
Scientific paper
10.1086/375151
We examine in detail the dynamical structure of an elliptical galaxy simulated in the Lambda CDM scenario. The morphology of the galaxy evolves dramatically over time in response to the mode and timing of mass accretion; smooth deposition of cooled gas leads to the formation of centrifugally supported disks, whilst major mergers disperse stellar disks into spheroids. These two modes of accretion alternate successively until z~0.6, when the galaxy undergoes one last major (1:2) merger that consumes much of the remaining gas into stars. Little gas cools and accretes subsequently and, as a result, most stars at z=0 are in a spheroidal component that resembles present-day elliptical galaxies. Dynamically, the galaxy is well approximated by an E4 oblate rotator. Boxy isophotes are obtained when the galaxy is seen face-on and Vrot/sigma<<1. On the other hand, disky isophotes are found for inclinations which maximize Vrot/sigma. The line-of-sight velocity distribution is nearly Gaussian at all radii. The sign of the Gauss-Hermite skewness parameter h3 is anti-correlated with the apparent sense of rotation, in agreement with observed trends. The simulated galaxy has much higher effective surface brightness than normal ellipticals of similar luminosity, in a way reminiscent of the less common type of compact ellipticals. Our simulation shows that repeated episodes of dissipational collapse, followed by merger events, lead to stellar spheroids that are only mildly triaxial and of relatively simple kinematic structure. This is in better agreement with observation than earlier models based on dissipationless mergers of stellar disks, and a positive step towards reconciling the observed structure of ellipticals with the hierarchical merging scenario.
Eke Vincent R.
Meza Andres
Navarro Julio F.
Steinmetz Matthias
No associations
LandOfFree
Simulations of Galaxy Formation in a Lambda CDM Universe III: The Dissipative Formation of an Elliptical Galaxy 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 Simulations of Galaxy Formation in a Lambda CDM Universe III: The Dissipative Formation of an Elliptical Galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Simulations of Galaxy Formation in a Lambda CDM Universe III: The Dissipative Formation of an Elliptical Galaxy will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-219512