| DC 欄位 |
值 |
語言 |
| DC.contributor | 天文研究所 | zh_TW |
| DC.creator | 蔡明燕 | zh_TW |
| DC.creator | Ming-Yann Tsay | en_US |
| dc.date.accessioned | 2001-6-22T07:39:07Z | |
| dc.date.available | 2001-6-22T07:39:07Z | |
| dc.date.issued | 2001 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:88/thesis/view_etd.asp?URN= 88229009 | |
| dc.contributor.department | 天文研究所 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 由EUVE及BeppoSAX衛星對后髮座星系團的觀測發現，在65-245 eV波段（EUV波段）及20-80 keV波段（hard X-ray波段），有餘值輻射（excess emission）的出現。一般認為，於后髮座星系團內所偵測到的X-ray輻射，是由溫度約8 keV的氣體熱輻射而來。所謂的餘值輻射，以疊加在熱X-ray輻射上多餘輻射的形式出現。在EUV波段的餘值輻射，通常被認為是由能量幾百MeV的電子，經逆康普頓散射微波背景輻射光子後的結果，而在hard X-ray波段的餘值輻射來源目前仍有爭議。如果在EUV波段的餘值輻射是由逆康普頓散射而成，則我們可以藉此給定電子在能譜上能量γ約等於400附近的數量分布。同樣的，無線電輻射可以給定電子在能譜上能量γ約從700到4×104附近的數量分布。磁場強度將決定由無線電輻射資料導出的電子能量範圍。
我們提出連續注入電子模型，並計算在此模型下相對論性電子的可能能譜。我們進一步依照有無初始的強電子注入事件，將此模型分成二種亞型。在做模擬計算時，我們分別計算磁場為5μG及0.2μG下的相對論性電子能譜。由我們的模擬結果發現，餘值輻射在連續注入電子模型且有初始強電子注入事件的狀態下，無論在磁場為5μG或0.2μG，都能獲得很好的擬和。相對的，在連續注入電子模型且無初始強電子注入事件的狀況下，只有在磁場為0.2μG的狀況下，能獲得餘值輻射良好的擬和。 | zh_TW |
| dc.description.abstract | Observations carried out by Extreme Ultraviolet Explorer (EUVE) and the BeppoSAX on the Coma cluster detect excess emission, which is an extra emission superposed on what expected of a thermal X-ray emission and lies at both ends of this thermal X-ray emission. At the low-energy end between 65-245 eV (the
EUV excess), the excess is usually explained as inverse Compton emission by a few-hundred-MeV electrons up scattering the cosmic microwave background photons while the origin of the excess at the high-energy end between 20-80 keV is still in debate. The assumption of an inverse Compton scattering origin for the EUV excess can give a constraint on the electron spectrum at ? 400 while synchrotron radio emission will give a constraint on electron spectra in the energy range of ? 700 to ? 40000 depending on the strength of the magnetic field.
We propose models of continuous electron injections either with or without a major first event and carry out the modeling electron spectra by adopting two different magnetic fields, 5 and 0.2 G, which are as suggested by Faraday rotation measurements and as required for the inverse Compton interpretation of the observed hard X-ray excess emission. We nd that the observed excess emission can be perfectly explained by models of continuous electron injections with a major first event in both magnetic fields and models of continuous electron
injections without a major first event in low magnetic field. | en_US |
| DC.subject | 后髮座星系團 | zh_TW |
| DC.subject | 相對論性電子 | zh_TW |
| DC.subject | Coma galaxy cluster | en_US |
| DC.subject | Relativistic electrons | en_US |
| DC.title | 后髮座星系團內相對論性電子能譜的數值計算 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Numerical Calculations Of The Energy Spectrum Of Relativistic Electrons In The Coma Galaxy Cluster | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |