Imaging Spectroscopy of a Gradual Hardening Flare on 2000 November 25
| Autor: | Satoshi Masuda, Junko Kiyohara, J. Sato, Hiroyuki Takasaki, Ayumi Asai, Takaaki Yokoyama, Takeo Kosugi, Hiroshi Nakajima |
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| Rok vydání: | 2007 |
| Předmět: |
Physics
Spectral index Solar flare Astrophysics::High Energy Astrophysical Phenomena Gamma ray Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Spectral line law.invention Space and Planetary Science law Astrophysics::Solar and Stellar Astrophysics Spectroscopy Chromosphere Microwave Flare |
| Zdroj: | The Astrophysical Journal. 661:1234-1241 |
| ISSN: | 1538-4357 0004-637X |
| Popis: | We present an examination of multiwavelength observations of an M8.2 long-duration flare which occurred on 2000 November 25. During the flare, we can see a hard X-ray (HXR) source on one Hα flare ribbon in the HXR images obtained with the Hard X-ray Telescope aboard Yohkoh, and a compact microwave emission source on the other flare ribbon in the data taken with the Nobeyama Radioheliograph, while we can also see an extended microwave emission source that connects both of these emission sources. The compact microwave and HXR sources clearly showed gradual hardening tendencies in their spectra. In addition, we found energy-dependent delays of the peak times in the HXR bursts and concluded that almost all of the accelerated electrons are trapped in magnetic loops to generate the extended microwave source and are dripping into the chromosphere at the compact microwave and the HXR emission sites. We then performed imaging spectroscopic analyses to the microwave emission sources. The temporal evolutions of the flux and the spectral index of the compact microwave footpoint source are quite similar to those of the HXR source, which is mainly emitted at the other footpoint, while those at the loop-top extended source do not show this similarity. Moreover, there is a constant gap between the electron spectral index derived from the microwave footpoint source and that from the HXR source. We also discuss the constant gap, based on the trapped and dripping model. |
| Databáze: | OpenAIRE |
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