We report on our continuing efforts to compare the absolute effective areas of the current generation of CCD instruments onboard the active observatories, specifically: Chandra ACIS, XMM-Newton EPIC (MOS and pn), Suzaku XIS, and Swift XRT, using 1E 0102.2-7219, the brightest supernova remnant in the Small Magellanic Cloud. 1E 0102.2-7219 has strong lines of O, Ne, and Mg below 1.5 keV and little Fe emission to complicate the spectrum. The spectrum of 1E 0102.2-7219 has been well-characterized using the RGS grating instrument on XMM-Newton and the HETG grating instrument on Chandra. We have developed an empirical model that includes Gaussians for the identified lines, an absorption component in the Galaxy, another absorption component in the SMC, and two continuum components with different temperatures. In our fits, the model is highly constrained in that only the normalizations of the four brightest line complexes (the OVII triplet, OVIII Ly? line, the NeIX triplet, and the NeX Ly?) and an overall normalization are allowed to vary, while all other components are fixed. We adopted this approach to provide a straightforward comparison of the measured line fluxes at these four energies. We find that the measured fluxes of the OVII triplet, the OVIII Ly?line, the NeIX triplet, and the NeX Ly?line generally agree to within /-10% for all instruments, with the exception of the OVII triplet and the OVIII Ly?line normalizations for the Suzaku XIS1, XIS2, & XIS3, and the Swift XRT, which can be up to 20%lower compared to the reference model.
