Aufbauleuchte can be called a 'ceiling luminaire'. The "Wanne" is usually a diffuser or possibly "troffer', for example Wannen-Einbauleuchte - recessed diffuser luminaire, or Einbau-Wanneleuchte -troffer luminaire. About six months, I had to translate something along these lines and researched in the great web. Unfortunately, I cannot remember where I found these translations.