Gaussian random field power spectrum and the S\'ersic law

The surface-brightness profiles of galaxies are well described by the S\'ersic law: systems with high S\'ersic index m have steep central profiles and shallow outer profiles, while systems with low m have shallow central profiles and steep outer profiles. R. Cen (2014, ApJL, 790, L24) has conjectured that these profiles arise naturally in the standard cosmological model with initial density fluctuations represented by a Gaussian random field (GRF). We explore and confirm this hypothesis with N-body simulations of dissipationless collapses in which the initial conditions are generated from GRFs with different power spectra. The numerical results show that GRFs with more power on small scales lead to systems with higher m. In our purely dissipationless simulations the S\'ersic index is in the range 2
Comment: 6 pages, 2 figures, accepted for publication in the ApJL