Searching evidences for spiral shocks in the quiescent accretion disk of   U Gem
  We find that the quiescent accretion disk of U Gem has a complicated structure. Along to the bright spot originating in the region of interaction between the stream and the disk particles, there are also explicit indications of spiral shocks. The Doppler map and the variations of the peak separation of the emission lines are indicative. 
V. V. Neustroev (1), V. Chavushyan (2), J. R. Valdes (2) ((1) NUI   Galway, Ireland; (2) INAOE, Puebla, Mexico)