The dwarf Galaxy DDO 47: Testing Cusps Hiding in Triaxial Halos

G. Gentile; A. Burkert; P. Salucci; U. Klein; F. Walter

doi:10.1051/eas:2006089

Issue		EAS Publications Series Volume 20, 2006 Mass Profiles and Shapes of Cosmological Structures


Page(s)		279 - 280
DOI		https://doi.org/10.1051/eas:2006089
Published online		19 May 2006

Mass Profiles and Shapes of Cosmological Structures
G.A. Mamon, F. Combes, C. Deffayet and B. Fort (eds)
EAS Publications Series, 20 (2006) 279-280

The dwarf Galaxy DDO 47: Testing Cusps Hiding in Triaxial Halos

G. Gentile¹, A. Burkert², P. Salucci¹, U. Klein³ and F. Walter⁴

¹ SISSA, Via Beirut 2, 34014 Trieste, Italy
² Universitäts-Sternwarte München, Scheinerstr. 1, 81679 München, Germany
³ RAIUB, Auf dem Hügel 71, 53121 Bonn, Germany
⁴ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany

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 ΛCDM 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. (2005).