Charge-Exchange Spectra of Hydrogenic and He-Like Iron

Author

B. J. Wargelin
P. Beiersdorfer
P. A. Neill
Ronald E. Olson, Missouri University of Science and TechnologyFollow
J. H. Scofield

Abstract

We present H-like Fe XXVI and He-like Fe XXV charge-exchange spectra resulting from collisions of highly charged iron with N₂ gas at an energy of ∼10 eV amu-1 in an electron beam ion trap. Although individual high-n emission lines are not resolved in our measurements, we observe that the most likely level for Fe⁺²⁵ → Fe⁺²⁴ electron capture is nmax ∼ 9, in line with expectations, while the most likely value for Fe⁺²⁶ → Fe⁺²⁵ charge exchange is significantly higher. in the Fe XXV spectrum, the Kα emission feature dominates, whether produced via charge exchange or collisional excitation. the Kα centroid is lower in energy for the former case than for the latter (6666 vs. 6685 eV, respectively), as expected because of the strong enhancement of emission from the forbidden and intercombination lines, relative to the resonance line, in charge-exchange spectra. in contrast, the Fe XXVI high-n Lyman lines have a summed intensity greater than that of Lyα and are substantially stronger than predicted from theoretical calculations of charge exchange with atomic H. We conclude that the angular momentum distribution resulting from electron capture using a multielectron target gas is significantly different from that obtained with H, resulting in the observed high-n enhancement. a discussion is presented of the relevance of our results to studies of diffuse Fe emission in the Galactic center and Galactic ridge, particularly with Astro-E2/Suzaku. © 2005. the American Astronomical Society. All rights reserved.

Recommended Citation

B. J. Wargelin et al., "Charge-Exchange Spectra of Hydrogenic and He-Like Iron," Astrophysical Journal, vol. 634, no. 1 I, pp. 687 - 697, American Astronomical Society; IOP Publishing, Nov 2005.

The definitive version is available at https://doi.org/10.1086/496874

Department(s)

Physics

Keywords and Phrases

Atomic data; Atomic processes; X-rays: diffuse background; X-rays: general

International Standard Serial Number (ISSN)

1538-4357; 0004-637X

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2024 The Authors, All rights reserved.

Creative Commons Licensing

This work is licensed under a Creative Commons Attribution 4.0 License.

Publication Date

20 Nov 2005