Density profile slope in Dwarfs and environment

Abstract

In the present paper, we study how the dark matter density profiles of dwarfs galaxies in the mass range $10^8-10^{10}{M}_{\odot }$ are modified by the interaction of the dwarf in study with the neighboring structures, and by changing baryon fraction in dwarfs. As already shown in Del Popolo (2009), the slope of density profile of inner halos flattens with decreasing halo mass and the profile is well approximated by a Burkert's profile. The analysis shows that dwarfs who suffered a smaller tidal torquing (consequently having smaller angular momentum) are characterized by steeper profiles with respect to dwarfs subject to higher torque, and similarly dwarfs having a smaller baryons fraction have also steeper profiles than those having a larger baryon fraction. In the case tidal torquing is shut down and baryons are not present, the density profile is very well approximated by an Einasto profile, similarly to dwarfs obtained in dissipationless N-body simulations. We then apply the result of the previous analysis to the dark matter halo rotation curves of three different dwarfs, namely NGC 2976, known to have a flat inner core, NGC 5949 having a profile intermediate between a cored and a cuspy one, and NGC 5963 having a cuspy profile. After calculating baryon fraction, which is $\simeq 0.1$ for the three galaxies, we fitted the rotation curves changing the value of angular momentum. NGC 2976, has an higher value of ordered angular momentum ($\lambda \simeq 0.04$) with respect to NGC 5949 ($\lambda \simeq 0.025$) and in the case of NGC 5963 the very steep profile can be obtained with a low value of $\lambda$ ($\lambda \simeq 0.02$) and also decreasing the value of the random angular momentum. In the case of NGC 2976 tidal interaction with M81 could have also influenced the inner part of the density profile.

15 pages; 5 figures; 1 table

References in corpus (17)

• High-Resolution Rotation Curves and Galaxy Mass Models from THINGS
• Forming Disk Galaxies in Lambda CDM Simulations
• Assembly bias in the clustering of dark matter haloes
• Cosmological puzzle resolved by stellar feedback in high redshift galaxies
• The central slope of dark matter cores in dwarf galaxies: Simulations vs. THINGS
• Spin alignment of dark matter haloes in filaments and walls
• The Baryon Content of Extremely Low Mass Dwarf Galaxies
• NGC 3741: dark halo profile from the most extended rotation curve
• GHASP : an H alpha kinematic survey of spiral and irregular galaxies. V. Dark matter distribution in 36 nearby spiral galaxies
• Erasing Dark Matter Cusps in Cosmological Galactic Halos with Baryons
• Radial distribution of stars, gas and dust in SINGS galaxies. III. Modeling the evolution of the stellar component in galaxy disks
• The Sphericalization of Dark Matter Halos by Galaxy Disks
• Are Dwarf Galaxies Dominated by Dark Matter?
• On the Correlation between Spin Parameter and Halo Mass
• Secondary infall and dark matter haloes
• Environment and mass dependencies of galactic $\lambda$ spin parameter: cosmological simulations and observed galaxies compared
• Quantifying galactic morphological transformations in the cluster environment

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