J. M. Alimi | Searcharxiv

arXiv2010

Primordial non-Gaussianity in density fluctuations

We present N-body cosmological numerical simulations including a primordial non-Gaussianity in the density fluctuation field quantified by the non-linear parameter $f_{NL}$. We have used MPGRAFIC code to produce initial conditions and the Adaptive Mesh Refinement (AMR) code RAMSES to evolve the large scale structure formation. We estimated the higher order momenta of the initial distribution of density fluctuations, investigated the redshift evolution of the non-linear power spectrum and estimated the discrepancy introduced by the primordial non-Gaussianity in the non-linear power spectrum.

astro-ph.CO↗

arXiv1993

Subclustering and Luminous-Dark Matter Segregation in Galaxy Clusters

We have performed a series of N-body experiments on Connection Machine-5 in order to simulate the formation of galaxy clusters gravitationally dominated by a massive dark background. In accordance with previous authors we find an extremely inhomogeneous evolution where subcondensations are continually formed and merged. The final distribution of galaxies is more centrally condensed than that of dark matter particles. We have analyzed the origin of this galaxy-dark matter segregation and also the origin of subclustering leading to this effect. We have then analysed, analytically and numerically, the dependence of final segregation on the physical parameters characterizing the model of protocluster. We also find that such a segregation persists even when inelastic encounters of dark halos around galaxies are taken into account. We conclude that this effect cannot be in general avoided in any hierarchical clustering scenario.

astro-ph↗