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The dwarf galaxy DDO 47: testing cusps hiding in triaxial halos

G. Gentile·A. Burkert·P. Salucci·U. Klein·F. Walter
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Abstract

We present HI data of the dwarf galaxy DDO 47, aimed at testing the hypothesis that dark halo triaxiality might induce non-circular motions resulting in rotation curves best fitted by cored halos, even if the dark matter halo is intrinsically cuspy. We performed a harmonic decomposition of the velocity field in order to search for alleged non-circular motions needed to ``hide'' a cusp: in DDO 47 non-circular motions are globally at a level of 2-3 km s$^{-1}$, far from being sufficient to reconcile the observed rotation curve with the $Λ$CDM predictions. We conclude that the dark matter halo around DDO 47 is truly cored and that a cusp cannot be hidden by non-circular motions. More details are shown in Gentile et al. (2006, ApJL in press, astro-ph/0506538).

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G. Gentile, A. Burkert, P. Salucci, U. Klein, F. Walter. 2005-10-20. The dwarf galaxy DDO 47: testing cusps hiding in triaxial halos. https://doi.org/10.1051/eas%3A2006089

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