Resolving Low energy lines from LMXRB

ASCA obsevations of the LMXRB X091854,X154362 and X0614+09 reveal strongemission lines in the 0.51 keV band.The emission is consistent with O and Fe L,but major uncertanties remain in establishing the line emission mechanism. Therecombination continuum,a signature of photoionization, is missing or at lowerlevel in all systems. A collisional plasma better reproduces the spectrum.Scattering and 3body recombinations are other possible mechanism that can lowerthe recombination.We propose to observe X091854 and X154362 with the XMMgratings.These observations will differentiate line emission with anunprecedented resolving power. This capability will pin down the mechanismresponsible for the line emission, and define abundances to constrain the system truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]