Size matters: the non-universal density profile of subhaloes in SPH simulations and implications for the Milky Way's dSphs

Abstract

We use dark matter only and full hydrodynamical Constrained Local UniversE Simulations (CLUES) of the formation of the Local Group to study the density profile of subhaloes of the simulated Milky Way and Andromeda galaxies. We show that the Einasto model provides the best description of the subhaloes' density profile, as opposed to the more commonly used NFW profile or any generalisation of it. We further find that the Einasto shape parameter \nEin\ is strongly correlated with the total subhalo mass, pointing towards the notion of a non-universality of the subhaloes' density profile. We observe that the effect of mass loss due to tidal stripping, in both the dark matter only and the hydrodynamical run, is the reduction of the shape parameter \nEin\ between the infall and the present time. Assuming now that the dSphs of our Galaxy follow the Einasto profile and using the maximum and minimum values of \nEin\ from our hydrodynamical simulation as a gauge, we can improve the observational constraints on the \Rmax-\Vmax\ pairs obtained for the brightest satellite galaxies of the Milky Way. When considering only the subhaloes with $-13.2\lesssim M_V\lesssim -8.8$, i.e. the range of luminosity of the classical dwarfs, we find that all our simulated objects are consistent with the observed dSphs if their haloes follow the Einasto model with $1.6\lesssim n_{\mathrm{E}}\lesssim 5.3$. The numerically motivated Einasto profile for the observed dSphs will alleviate the recently presented "massive failures" problem.

11 pages, 5 figs, MNRAS accepted version, figures added, section 4 expanded

References in corpus (18)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• The Milky Way's bright satellites as an apparent failure of LCDM
• A Method for Measuring (Slopes of) the Mass Profiles of Dwarf Spheroidal Galaxies
• Cuspy No More: How Outflows Affect the Central Dark Matter and Baryon Distribution in Lambda CDM Galaxies
• Subhaloes in Self-Interacting Galactic Dark Matter Haloes
• The redshift dependence of the structure of massive LCDM halos
• Baryons Matter: Why Luminous Satellite Galaxies Have Reduced Central Masses
• A Baryonic Solution to the Missing Satellites Problem
• The Missing Massive Satellites of the Milky Way
• Understanding the shape of the halo-mass and galaxy-mass cross-correlation functions
• The cold veil of the Milky Way stellar halo
• The dark matter halos of dwarf galaxies: a challenge for the LCDM paradigm?
• Not too big, not too small: the dark halos of the dwarf spheroidals in the Milky Way
• Improved Modeling of the Mass Distribution of Disk Galaxies by the Einasto Halo Model
• The Cosmic Abundance of Classical Milky Way Satellites
• Statistical properties of the dark matter haloes of dwarf galaxies and correlations with the environment
• Dark matter concentrations and a search for cores in Milky Way dwarf satellites

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