Calibrating the time-evolution of the high-energy emission of M stars

We aim at the detection of the quiescent Xray emission from the M dwarfLP61734, as invaluable calibration point for the activityage relation of Mdwarfs at the faint/old end. Analogous to our previous targets, LP61734 is awide companion to a white dwarf (WD), and we infer the age of the M dwarf (7.7Gyr) from the progenitor and cooling age of the WD. Our target is the oldestknown of such systems, and the only remaining one at >5Gyr that can be resolvedwith XMMNewton (separation virgul 22). Transient Xray emission was detected fromthe M dwarf during an XMMNewton slew but its quiescent emission is required toconstrain the activity age relation, which is key for understanding stellardynamos and the irradiation of planet atmospheres with highenergy photons. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]