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We aim to shed light on the physical properties and kinematics of themolecular material in the nucleus of one of the closest type 2 active galaxies.  To this end, we obtained high angular resolution ALMA observations of thenucleus of the Circinus galaxy. The observations map the emission at 350GHz and690GHz with spatial resolutions of ~3.8pc and ~2.2pc, respectively.  The continuum emission traces cold ($T\lesssim100$K) dust in a circumnucleardisk with spiral arms on scales of 25pc, plus a marginally resolved nuclearemission peak. The latter is not extended in polar direction as claimed basedon earlier ALMA observations. A significant amount (of the order of 40%) of the350GHz emission is not related to dust, but most likely free-free emissioninstead. We detect CO(3-2) and CO(6-5) as well as HCO$^+$(4-3), HCN(4-3), andCS(4-3). The CO emission is extended, showing a spiral pattern, similar to theextended dust emission. Towards the nucleus, CO is excited to highertransitions and its emission is self-absorbed, leading to an apparent hole inthe CO(3-2) but not the CO(6-5) emission. On the other hand, the high gasdensity tracers HCO$^+$, HCN, and CS show a strong, yet unresolved(($\lesssim4$pc) concentration of the emission at the nucleus, pointing at avery small 'torus'. The kinematics are dominated by rotation and point at ageometrically thin disk down to the resolution limit of our observations. Incontrast to several other AGNs, no HCN enhancement is found towards thenucleus.  The Circinus nucleus is therefore composed of at least two distinctcomponents: (1) an optically thin, warm outflow of ionised gas containingclouds of dust; and (2) a cold molecular and dusty disk. These findings supportthe most recent radiative transfer calculations of the obscuring structures inAGNs, which find a similar two-component structure. (Abridged)

ALMA imaging of the cold molecular and dusty disk in the type 2 active nucleus of the Circinus galaxy