http://arxiv.org/abs/1611.01409
The stellar and gaseous mass distributions, as well as the extended rotation curve in the nearby galaxy M33 are used to derive the radial distribution of dark matter density in the halo and to test cosmological models of galaxy formation and evolution. Two methods are examined to constrain dark mass density profiles. The first one deals directly with the fitting of the rotation curve data in the range of galacto-centric distances $0.24\,\text{kpc}\leq r\leq22.72\,\text{kpc}$. As found in a previous paper Corbelli 2014 et. al. and using the results of recent collisionless $\Lambda-$CDM numerical simulations, we confirm that the Navarro-Frenkel-White (NFW) dark matter profile provides a better fit to the rotation curve data than the cored Burkert (URC) profile. The second method relies on the local equation of centrifugal equilibrium and on the rotation curve slope. In the aforementioned range of distances, we fit an empirical velocity profile using a function which has a rational dependence on the radius. Following Salucci 2010 et. al., we then derive an expression for the slope of the rotation curve and for the radial dependence of the local dark matter distribution. In the radial range $9.53\,\text{kpc}\leq r\leq22.72\,\text{kpc},$ where the uncertainties induced by the luminous matter (stars and gas) become negligible, we tested again the NFW and the URC dark matter profiles. With this second method, we confirm that both profiles are compatible with the data even though in this case the cored Burkert mass density profile provides a better fit to the data and a more reasonable value for the barionic-to-dark matter ratio.
E. Fune, P. Salucci and E. Corbelli
Mon, 7 Nov 16
2/48
Comments: 9 pages, 10 figures
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