Differential Emission Measure Determination of Collisionally Ionized Plasma: Application to Hot Stars

摘要

We describe a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribu-tion, of collisionally ionized hot plasmas from their X-ray emission line spectra. This technique involves fitting spectra using a number of components, each of which is the entire X-ray line emission spectrum for a single ion. It is applicable to high-resolution X-ray spectra of any collisionally ionized plasma and partic-ularly useful for spectra in which the emission lines are broadened and blended such as those of the winds of hot stars. This method does not require that any explicit assumptions about the form of the DEM distribution be made and is easily automated. We apply our technique to the Chandra HETGS spectra of nine hot stars.