088487

We propose a triggered observation of the highest magnetized polar AR UMa. Ourtarget with a magnetic field of about 230MG gives access to an as yet unexploredparameter regime of magnetic accretion. It escaped a high-state X-rayobservation so far due to an extended low state. Utilizing the broad spectralrange covered by XMM-Newton including the OM we will simultaneously determinethe energy content of the main cooling channels of the accretion plasma:cyclotron radiation in the UV plasma radiation in hard X-rays and re-processedradiation in soft X-rays. We will compare our observations with accretion columnmodels and study quantitatively the energy balance of the cooling plasma as afunction of the accretion rate and the magnetic field strength. [truncated! Please see actual data for full text]