頁籤選單縮合
題名 | A Multi-Wavelength Study of X-Ray Jets in Active Galaxies=對活躍星系X射線噴流的多波段研究 |
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作者 | 黃貞媛; 陳林文; Huang, Zhen-yuan; Chen, Lin-wen; |
期刊 | 臺北天文館學報 |
出版日期 | 20051200 |
卷期 | 3 民94.12 |
頁次 | 頁18-26 |
分類號 | 323.18 |
語文 | eng |
關鍵詞 | X射線噴流; 活躍星系核; 輻射機制; X-ray jets; AGN; Radiation mechanisms; |
中文摘要 | 利用多波段的觀測數據,我們進行一系列對活躍星系中高能輻射噴流本質的探討。經由這幾年的研究,產生這些X 射線噴流的主要輻射機制通常可歸結成同步加速輻射(synchrotron ),逆康普敦散射宇宙微波背景光子(IC/CMB) ,或同步自康普敦散射(SSC) 。然而目前對所有已觀測的X 射線噴流並無一致的解釋,同時不同輻射模型所預測的物理環境也常隨之變化。為了有系統地檢驗已知的高能噴流,以及更廣泛地探討X 射線噴流的起源,我們利用從電波波段到X 射線的觀測數據,加上一個能同時涵蓋上述三種輻射機制的合成模型(synthesis model) 來深入研究在這些X 射線噴流中,不同輻射機制所占的組成比例與其物理參數。從我們的分析顯示,在目前已知皆有電波、可見光、及X 射線輻射的噴流中,SSC 機制似乎為主導光學波段的輻射來源,而X 射線卻主要源自於IC/CMB 機制。利用這些數據以及合成模型,噴流物理環境中的都普勒因子與磁場的可能範圍可進一步被縮小。此外,藉由其他觀測所獲得的束射因子(beaming factor ),我們也對部分噴流的能量傳播問題進行一些討論。我們發現同步加速輻射強度隨著遠離活躍星系核而遞減至離核心約100 kpc 處;然而以SSC 為主的輻射源數量卻在此處達到峰值。這可能是第一個指出X 射線噴流傳播距離極限的證據。 |
英文摘要 | To probe the high-energy origin of AGN jets, a series of analysis incorporating all available X-ray jet data with a synthesis model are carried out, in which the model includes synchrotron radiation, synchrotron self-Compton emission (SSC), and inverse Compton scattering off CMB photons (IC/CMB) – the main radiation mechanisms of X-ray jets as current consensus suggests. It has been demonstrated that synchrotron-dominated and inverse-Compton-dominated jets can be separated into two groups by comparison of broadband spectral indices; using the similar technique but with a more sophisticated analysis, we have further estimated the possible contributions respectively from the three mechanisms to the observed fluxes of our samples. Our analysis shows that the SSC mechanism is responsible for most optical emission while the IC/CMB model is the major contributor in X-ray; subsequently, the Doppler boosting factor and magnetic field of jets are constrained by the contribution fractions of the three mechanisms. Moreover, with the constrained beaming factors, the de-projected distance of each sample is calculated to determine the emission nature of jet propagation. There is an interesting trend showing that the synchrotron emission declines out to 100 kpc away from AGN cores and incidentally most of the optical and X-ray emission produced by SSC appears significantly at around the same scale. This could be the first evidence to indicate the average transportation limit of high-energy emission from jets. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。