摘要
详细介绍了由Edelson和Krolik提出的离散相关分析方法 ,该方法比较适合于因天文观测的不规则性而引起的时间分布不均匀的不同波段之间流量的相关分析 .取两种极端的情况 (完全相关和完全不相关 )对该方法进行了测试 ,结果表明这是一种比较切实可行的方法 .利用它 ,对AO 0 2 3 5 +1 6 4在 4个波段上流量变化作相关性分析 ,结果表明 ,AO 0 2 3 5 +1 6 4在 5GHz、8GHz、1 4.5GHz和光学B波段的辐射之间存在着明显的相关性 ,高频波段的流量变化早于低频波段的流量变化 ,表明这些波段的辐射 (从射电到光学 )可能来源于相同的辐射机制 ,或者辐射是相关的 .另外发现 ,谱指数随着时间而发生变化 ,这种变化在 5GHz、8GHz和 1 4.5GHz之间多表现为逆谱的形式 .种种迹象表明AO 0 2 3 5 +1 6 4的射电爆发可能是和激波的形成有关 ,多波段的频谱分析和频谱演化研究可能是揭示这种关系的有效途径 .
We introduce the method of discrete correlation function supposed by Edelson & Krolik, which is fit to the correlation analysis of unevenly time-distributed flux density data due to irregular astronomical observations between different wavebands. We tested the method with two opposite extreme situations of perfect correlation and perfect un-correlation. The test results show that the DCF method is feasible. With the method, we have done the correlation analyses of the object at four wavebands. The results show that the radiative variation between 5 GHz, 8 GHz, 14.5 GHz and optical B band are of clear correlativity with earlier and faster variation at higher frequency than that at lower frequency. This may imply that the emissions at these bands (from radio to optical band) originate from the same radiative process, or the emissions are correlated. In addition, we find that the spectral index at radio bands varies with time, showing the form of inverse spectrum. Various kinds of evidences indicate that the outbursts are associated with the forming of shocks in relativistic jets. The spectral analyses of multiple wave bands and the studies of spectral evolution may be the effective way to reveal the problem.
出处
《天文学报》
CSCD
北大核心
2001年第3期287-301,共15页
Acta Astronomica Sinica
基金
国家自然科学基金 (No .G1 9990 75 4)资助
