Transcript Slide 1

Low Temperature Dielectronic Recombination (DR) Data for Modeling
Photoionized Cosmic Plasmas (D. W. Savin, PI – Columbia University)
The heavy ion Test Storage Ring (TSR) at the Max Planck
Institute for Nuclear Physics (MPIK) In Heidelberg, Germany.
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Interpreting spectra from photoionized
plasmas requires accurate ionization
balance calculations.
For most ions, DR is the dominant
electron-ion recombination mechanism.
Our laboratory work has found significant
errors in the recommended DR data.
Measurements are carried out using TSR
(upper left) in collaboration with the groups
of Andreas Wolf (MPIK) and Alfred Müller
(University of Giessen).
Recent Chandra and XMM observations
have detected absorption features due to
M-shell iron ions.
Uncertainties in the relevant iron M-shell
low temperature DR limit our ability to fit
this portion of the AGN spectrum.
Our recent work indicates that modern DR
theory is unable to reliably calculate the
relevant DR resonances (e.g., lower left).
See the talk by Daniel Savin for details.