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E.A. Evstigneeva R.R. de Carvalho A.L. Ribeiro H.V. Capelato 《Astrophysics and Space Science》2003,284(2):487-490
We present the preliminary results of a study of how small stellar systems merge to form larger ones. As we display the families
of galaxies in the μe - Re plane (effective surface brightness versus effective radius) we realize that different morphological types occupy different
loci, evidencing the different physical mechanisms operating in each family. As proposed by Capaccioli et al. (1992) this
diagram is the logical equivalent of the HR diagram for stars. Here we take some initial steps in understanding of how we
can establish the evolutionary tracks, solely due to dynamical processes, in the μe - Re plane, ultimately making a dwarf elliptical to turn into a normal elliptical galaxy.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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D. Gerbal H.V. Capelato F. Durret G.B. Lima Neto I. Márquez 《Astrophysics and Space Science》2001,276(2-4):861-868
We suggest that elliptical galaxies, as stellar systems in a stage of quasi-equilibrium, may have a specific entropy. We use
the Sérsic law to describe the light profile. The specific entropy (the Boltzmann–Gibbs definition) is then calculated assuming
that the galaxy behaves as a spherical, isotropic, one-component system. We predict a relation between the three parameters
of the Sérsic law linked to the specific entropy, defining a surface in the parameter space, an ‘entropic plane’. We have
analysed a sample of simulated merging elliptical galaxies (virtual) and a sample of galaxies belonging to the Coma Cluster (real). Both virtual and realgalaxies are: 1) located in their own ‘entropic plane‘ and 2) in this plane, they are located on a straight line, indicating
constant entropy: another physical property A careful examination of the value of the specific entropy indicates a very small
increase in the specific entropy with the generation after merging (virtual sample). Although one cannot distinguish between various generations for real galaxies, the distribution of specific entropy in this sample is very similar to that in the virtual sample.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Using eigenmode expansion of the Mark III and SFI surveys of cosmological radial velocities, a goodness-of-fit analysis is applied on a mode-by-mode basis. This differential analysis complements the Bayesian maximum likelihood analysis that finds the most probable model given the data. Analyzing the surveys with their corresponding most likely models from the CMB-like family of models, as well as with the currently popular LambdaCDM model, reveals a systematic inconsistency of the data with these "best" models. There is a systematic trend of the cumulative chi(2) to increase with the mode number (where the modes are sorted by decreasing order of the eigenvalues). This corresponds to a decrease of the chi(2) with the variance associated with a mode and hence with its effective scale. It follows that the differential analysis finds that on small (large) scales the global analysis of all the modes "puts" less (more) power than actually required by the data. This observed trend might indicate one of the following: (1) the theoretical model (i.e., power spectrum) or the error model (or both) have an excess of power on large scales, (2) velocity bias, or (3) the velocity data suffers from systematic errors that have not yet been corrected. 相似文献
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H. V. Capelato G. Des Forets A. Mazure E. Salvador-Sole 《Astrophysics and Space Science》1985,108(2):363-368
The analysis of the luminosity segregation in the 0004.8–3450 cluster of galaxies is made which reinforces the assumption of merging mechanisms. 相似文献
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