On the dark matter haloes inner structure and galaxy morphology

Abstract

In the present paper, we extend the study of Del Popolo (2010) to determine the slope of the inner density profile of galaxy haloes with different morphologies. We study how galaxy morphology changes the relation between the inner slope of the galaxy halo density profile, $\alpha$, and the stellar mass, $M_{\ast }$, or rotation velocity $V_{\mathrm{rot}}$. For this, we use the model of Del Popolo (2009) in combination with observed data from the Romanowsky \& Fall (2012) sample of elliptical and spiral galaxies, the Local Group sample compiled by McConnachie (2012), and the simulation results by Cloet-Osselaer et al. (2014). We find that the slope $\alpha$ flattens monotonically, from $\alpha \simeq -1$ at $V_{\mathrm{rot}}\simeq 250$ km/s, to $\alpha \simeq 0$. After $V_{\mathrm{rot}}\simeq 25$ km/s the slope starts to steepen. The steepening happens in the mass range dominated by non-rotationally supported galaxies (e.g., dSphs) and depends on the level of offset in the angular momentum of rotationally and non-rotationally dominated galaxies. The steepening is a consequence of the decrease in baryons content, and angular momentum in spheroidal dwarf galaxies. We finally compare our result to the SPH simulations of Di Cintio. Our result is in qualitatively agreement with their simulations, with the main difference that the inner slope $\alpha$ at small stellar masses ($M_{\ast }\lesssim 10^8{M}_{\odot }$) is flatter than that in their simulations. As a result, the claim that finding a core in dwarf galaxies with masses slightly smaller than $\simeq 10^6{M}_{\odot }$, (as in the Di Cintio, or Governato, supernovae feedback mechanism) would be a problem for the $\Lambda$CDM model must be probably revised.

27 pages, 5 figures, published in Astronomy & Space Science

References in corpus (30)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Too big to fail? The puzzling darkness of massive Milky Way subhaloes
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• High-resolution mass models of dwarf galaxies from LITTLE THINGS
• Stellar Feedback in Dwarf Galaxy Formation
• Bulge Formation by the Coalescence of Giant Clumps in Primordial Disk Galaxies
• The kinematic status and mass content of the Sculptor dwarf spheroidal galaxy
• Cosmological puzzle resolved by stellar feedback in high redshift galaxies
• Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5<z<3
• The Galaxy and its stellar halo: insights on their formation from a hybrid cosmological approach
• Clumpy Galaxies in GOODS and GEMS: Massive Analogs of Local Dwarf Irregulars
• Erasing Dark Matter Cusps in Cosmological Galactic Halos with Baryons
• Baryonic Pinching of Galactic Dark Matter Halos
• Dynamical Centers and Non-Circular Motions in THINGS Galaxies: Implications for Dark Matter Halos
• The Kozai-Lidov Mechanism in Hydrodynamical Disks
• Dwarf Galaxy Dark Matter Density Profiles Inferred from Stellar and Gas Kinematics
• Dark Matter Heating and Early Core Formation in Dwarf Galaxies
• Dissecting Galaxy Formation: I. Comparison Between Pure Dark Matter and Baryonic Models
• Early flattening of dark matter cusps in dwarf spheroidal galaxies
• Dark matter and structure formation a review
• Determining the Nature of Dark Matter with Astrometry
• Shear and rotation in Chaplygin cosmology
• Nonlinear evolution of dark matter subhalos and applications to warm dark matter
• The internal dynamics of the Local Group dwarf elliptical galaxies NGC147, NGC185, and NGC205
• A unified solution to the small scale problems of the $\Lambda$CDM model II: introducing parent-satellite interaction
• Numerical simulations of dwarf galaxy merger trees
• The Dynamics and Metallicity Distribution of the Distant Dwarf Galaxy VV124
• Nearby Clumpy, Gas Rich, Star Forming Galaxies: Local Analogs of High Redshift Clumpy Galaxies
• The flat density profiles of massive, and relaxed galaxy clusters

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