Bursting and quenching in massive galaxies without major mergers or AGNs |
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| Authors: | Yuval Birnboim Avishai Dekel Eyal Neistein |
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| Institution: | Instituto de Astrofisica de Andalucia (CSIC), E18008 Granada, Spain;Instituto de Astrofisica de Canarias, C/Via Lactea s/n, Tenerife E38200, Spain;Facultad de Fisica, Universidad de La Laguna, Astrofisico Francisco Sanchez, s/n, La Laguna, Tenerife E38200, Spain |
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| Abstract: | In this work, we study the formation and evolution of dark matter haloes by means of the spherical infalling model with shell-crossing. We present a framework to tackle this effect properly based on the numerical follow-up, with time, of that individual shell of matter that contains always the same fraction of mass with respect to the total mass. In this first step, we do not include angular momentum, velocity dispersion or triaxiality. Within this framework – named as the spherical shell tracker – we investigate the dependence of the evolution of the halo with virial mass, with the adopted mass fraction of the shell, and for different cosmologies. We find that our results are very sensitive to a variation of the halo virial mass or the mass fraction of the shell that we consider. However, we obtain a negligible dependence on cosmology. Furthermore, we show that the effect of shell-crossing plays a crucial role in the way that the halo reaches the stabilization in radius and the virial equilibrium. We find that the values currently adopted in the literature for the actual density contrast at the moment of virialization, δvir , may not be accurate enough. In this context, we stress the problems related to the definition of a virial mass and a virial radius for the halo. The question of whether the results found here may be obtained by tracking the shells with an analytic approximation remains to be explored. |
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| Keywords: | methods: numerical cosmology: theory dark matter large-scale structure of Universe |
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