Spatially resolved spectra of the accretion disc of the nova-like variableUU Aquarii

Time-resolved spectroscopy of the nova-like variable UU Aquarii is analysed with eclipse mapping techniques to produce spatially resolved spectra of i ts accretion disc and gas stream as a function of distance from disc centre in the range 3600-6900 Angstrom. The spatially resolved spectra show that the continuum emission becomes progressively fainter and redder for increas ing disc radius - reflecting the radial temperature gradient - and reveal t hat the H I and He I Lines appear as deep, narrow absorption features in th e inner disc regions, transitioning to emission with P Cyg profiles for int ermediate and large disc radii. The spectrum of the uneclipsed component ha s strong H I and He I emission lines plus a Balmer jump in emission, and is explained as optically thin emission from a vertically extended disc chrom osphere + wind. Most of the line emission probably arises from the wind. Th e spatially resolved spectra also suggest the existence of gas stream 'disc -skimming' overflow in UU Aqr, which can be seen down to R similar or equal to 0.2R(L1) The comparison of our eclipse maps with those of Baptista, Ste iner & Horne suggests that the asymmetric structure in the outer disc previ ously identified as the bright-spot may be the signature of an elliptical d isc similar to those possibly present in SU UMa stars during superoutbursts .