X-ray emission from dust in hot plasmas

被引：14

作者：

Borkowski, KJ ^{[1
]}

Szymkowiak, AE ^{[1
]}

机构：

[1] NASA,GODDARD SPACE FLIGHT CTR,GREENBELT,MD 20771

来源：

ASTROPHYSICAL JOURNAL | 1997年 / 477卷 / 01期

基金：

美国国家航空航天局;

关键词：

dust; extinction; supernova remnants; X-rays; ISM;

D O I：

10.1086/310522

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Energetic (few keV) thermal electrons easily penetrate interstellar dust grains immersed in hot plasmas. These electrons create K-shell vacancies in atoms locked in dust grains through the K-shell collisional ionization process. Heavy elements such as Fe and Ca produce fluorescent K alpha emission in the subsequent decay of the inner shell vacancy. We predict that this emission from Fe atoms in dust grains should be present in X-ray spectra emitted by dusty plasma, in addition to K alpha emission from highly ionized Fe ions. This affects the strength and shape of the Fe K alpha complex. We also predict a low ratio of L-shell/K alpha emission for dust grains, because of low fluorescent yields for L-shell transitions. These effects should be most pronounced in young supernova remnants (SNRs). We discuss observational evidence for the fluorescent Fe K alpha emission from dust in X-ray spectra of Tycho's, Kepler's, and Cassiopeia A SNRs, the three youngest remnants in our Galaxy.

引用

页码：L49 / L52

页数：4

共 19 条

[1] X-RAY WAVELENGTHS [J].