088274

We propose XMM-Newton observations of 4 newly discovered long-period AM CVn systems. Our goals are: (1) determine the X-ray fluxes of these objects to help understand how they can be identified in future surveys and test the nature of the X-ray emission region (2) do eclipse mapping in both X-ray and UV to understand the relative contributions of the accreting white dwarf and boundary layer versus the larger accretion disks (3) if the systems are on the bright end of the possible range (which is likely) use their X-ray spectral shapes to estimate their masses from cooling flow models while if they are on the faint end use the measured fluxes to plan future longer observations. [truncated! Please see actual data for full text]