Hannover 2010 – wissenschaftliches Programm
A 26.2: Hauptvortrag
Freitag, 12. März 2010, 11:00–11:30, B 302
Astrophysically motivated electron collisions studies on M-shell iron ions — •Michael Lestinsky1, Oldřich Novotný1, Michael Hahn1, Dietrich Bernhardt2, Stefan Schippers2, Alfred Müller2, Claude Krantz3, Manfred Grieser3, Roland Repnow3, Andreas Wolf3, Nigel Badnell4, and Daniel Wolf Savin1 — 1Columbia Astrophysics Laboratory, New York — 2Institut für Atom- und Molekükphysik, Justus-Liebig-Universität, Gießen — 3Max-Planck-Institut für Kernphysik, Heidelberg — 4Department of Physics, University Strathclyde, Glasgow
Satellite X-ray observatories routinely observed spectroscopic features from M-shell iron ions in various cosmic sources. These observations are used to determine the properties of the observed objects. However, this requires accurate ionization balance calculations for the source which in turn necessitates reliable data for the electron-ion recombination process known as dielectronic recombination (DR) and also for electron impact ionization (EII). Utilizing the ion storage ring TSR, we are carrying out a series of energy-resolved DR and EII measurements in order to provide reliable for the astrophysics community. We compare our recent results for Fe11+ with modern theoretical calculations and with widely used models. Large differences are found in the low energy DR where an array of resonances enhances the measured DR by 102 as compared to theory. From our experimental data we derive plasma rate coefficients for both DR and EII for use in astrophysical models.