2010/10/12 by Neal Dalal, Yoram Lithwick, Dalal, Neal +3 · 2 citations
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.48550/arxiv.1010.2539
v2: updated references, submitted to ApJ
arxiv created 2010/10/22 · arxiv updated 2010/10/25
A longstanding puzzle of fundamental importance in modern cosmology has been the origin of the nearly universal density profiles of dark matter halos found in N-body simulations -- the so-called NFW profile. We show how this behavior may be understood, simply, by applying adiabatic contraction to peaks of Gaussian random fields. We argue that dynamical friction acts to reduce enormously the effect of random scatter in the properties of initial peaks, providing a key simplification. We compare our model predictions with results of the ultra-high resolution Via Lactea-II N-body simulation, and find superb agreement. We show how our model may be used to predict the distribution of halo properties like concentration. Our results suggest that many of the basic properties of halo structure may be understood using extremely simple physics.