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タイトル: | SUZAKU DISCOVERY OF THE STRONG RADIATIVE RECOMBINATION CONTINUUM OF IRON FROM THE SUPERNOVA REMNANT W49B |
著者: | Ozawa, M. Koyama, K. Yamaguchi, H. Masai, K. Tamagawa, T. |
著者名の別形: | 小澤, 碧 |
キーワード: | ISM: individual (W49B) radiation mechanisms: thermal supernova remnants X-rays: ISM |
発行日: | 30-Nov-2009 |
出版者: | The American Astronomical Society |
誌名: | The Astrophysical Journal |
巻: | 706 |
号: | 1 |
開始ページ: | L71 |
終了ページ: | L75 |
抄録: | We present a hard X-ray spectrum of unprecedented quality of the Galactic supernova remnant (SNR) W49B obtained with the Suzaku satellite. The spectrum exhibits an unusual structure consisting of a saw-edged bump above 8 keV. This bump cannot be explained by any combination of high-temperature plasmas in ionization equilibrium. We firmly conclude that this bump is caused by the strong radiative recombination continuum (RRC) of iron, detected for the first time in a SNR. The electron temperature derived from the bremsstrahlung continuum shape and the slope of the RRC is ~1.5 keV. On the other hand, the ionization temperature derived from the observed intensity ratios between the RRC and Kα lines of iron is ~2.7 keV. These results indicate that the plasma is in a highly overionized state. Volume emission measures independently determined from the fluxes of the thermal and RRC components are consistent with each other, suggesting the same origin of these components. |
著作権等: | © 2009 The American Astronomical Society |
URI: | http://hdl.handle.net/2433/139435 |
DOI(出版社版): | 10.1088/0004-637X/706/1/L71 |
出現コレクション: | 学術雑誌掲載論文等 |
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