Probing X-ray loop heights of giant active regions on fully convective stars

We have recently discovered a new way to determine the latitude of giant activeregions on fully convective M dwarfs, using rotationally modulated optical flarelight curves. This yielded a sample of four stars with welldetermined latitudesof their dominant active region. We aim to detect the potential rotationalmodulation of such an active region in Xrays and compare it to the detectedoptical modulation. This encodes information on the typical coronal loop heightsof such giant active regions on M dwarfs. We propose to collect EPIC lightcurves for the star in the sample that is suitable for Xray followup, coveringtwo stellar rotation periods for a total of 33 ks. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]