In the present paper, we extend the study of Del Popolo (Mon. Not. R. Astron. Soc. 408: 1808, 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-*, or rotation velocity, V-rot. For this, we use the model of Del Popolo (Astrophys. J. 698: 293, 2009) in combination with observed data from the Romanowsky and Fall (Astrophys. J. Suppl. Ser. 203: 17, 2012) sample of elliptical and spiral galaxies, the Local Group sample compiled by McConnachie (Astrophys. J. 144: 4, 2012), and the simulation results by Cloet-Osselaer et al. (Mon. Not. R. Astron. Soc. 442: 2909, 2014). We find that the slope alpha flattens monotonically, from alpha similar or equal to -1 at V-rot similar or equal to 250 km/s, to alpha similar or equal to 0. After V-rot similar or equal to 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 qualitative agreement with their simulations, with the main difference that the inner slope alpha at small stellar masses (M-* less than or similar to 10(8) M-circle dot) is flatter than that in their simulations. As a result, the claim that finding a core in dwarf galaxies with masses slightly smaller than similar or equal to 10(6) M-circle dot ( as in the Di Cintio, or Governato, supernovae feedback mechanism) would be a problem for the Lambda CDM model which should probably be revised.
|Titolo:||On the dark matter haloes inner structure and galaxy morphology|
|Data di pubblicazione:||2016|
|Appare nelle tipologie:||1.1 Articolo in rivista|