Fe L-shell lines from n (n=4, 5, 6) to 2 transitions

Fe L-shell emission lines at wavelengths less than 10 angstroms come from n (n great than 3) to 2 transitions. These lines embed information such as electron density and temperature that is of fundamental importance to understanding the physics of astrophysical objects. Unresolved by previous x-ray observatories, these low wavelength Fe lines are clearly observable by Chandra and XMM x-ray satellites. To meet the needs of using these lines as diagnostics, we have studied the n to 2 transitions (n = 4, 5, 6) Fe L-shell lines using the atomic codes HULLAC and FAC. Using the LLNL electron beam ion trap, we also made laboratory measurements for this wavelength region, following the success of our Fe L-shell emission lines for the 3-2 transitions (Brown et al, APJ supp. 2002). Our measurements and their comparison with code simulations will be reported, together with a discussion of the possible use of these low wavelength lines as diagnostics for astrophysics.

This work was performed under the auspices of the U.S. DOE by LLNL under contract No. W-7405-Eng-48 and supported by NASA SARA grants to LLNL, GSFC, and Columbia University.