Polar Disk Galaxies as new way to study galaxy formation: the case of NGC4650A

Abstract

NGC4650A is a polar disk galaxy: this is a peculiar object composed by a central spheroidal component, the host galaxy (HG), and an extended disk made up by gas, stars and dust, which orbits nearly perpendicular to the plane of the central galaxy. The existence of two decoupled components of the angular momentum let this object the ideal laboratory i) to study gravitational interactions and merging and ii) to constrain the 3D shape of its dark matter halo. In view of these applications, I will present two ongoing projects which aim to constrain i) the formation scenario for polar disks and ii) the dark halo content and shape, through a detailed analysis of the observed structure, metallicity and dynamics of NGC4650A.Comment: 4 pages, 2 figures, to appear in "Hunting for the Dark: The Hidden Side of Galaxy Formation", Malta, 19-23 Oct. 2009, eds. V.P. Debattista and C.C. Popescu, AIP Conf. Se