Fermi耀变体的能谱分布研究

从SSDC (Italian Space Agency Science Data Center)搜集了68个Fermi耀变体的射电至X射线波段的观测数据,用对数抛物线拟合计算了其同步辐射峰的参数.研究了有效谱指数、同步辐射峰值频率和曲率的关系并用有效谱指数估算同步峰频.主要结果有:(1)研究同步峰频和曲率的线性关系发现,对于全部的蝎虎天体(BL Lac),结果与能量依赖加速概率模型的预测一致.但是,如果仅仅考虑高峰频BL Lac,即同步峰频lg (ν_p/Hz)> 15.3的BL Lac,其结果却与分数变换加速增益模型的预测结果一致.(2)对于同步峰频相同的源,射电-光学的有效谱指数αro与曲率间有显著的负相关,而光学-X射线的有效谱指数α_ox与曲率无关.通过α_ro可以确定一个同步峰频与曲率的关系.

Spectral Energy Distribution for Some Fermi Blazars

Radio to X-ray observations are collected from SSDC(Italian Space Agency Science Data Center) for 68 Fermi blazars, and their spectral energy distributions(SED)of synchrotron peaks are calculated by using a lg-parabolic function. Based on the SED fitting parameters, the correlation between synchrotron peak frequency and curvature(and effective spectral index) is discussed, and an empirical function is also proposed to estimate the synchrotron peak frequency using effective spectral indexes. The main results are as follow:(1) From the linear correlation between the peak frequency(lg ν_p)and curvature(2k), we find that the result supports the energy-dependent acceleration probability model for all BL Lac, while the result for BL Lac with lg ν_p> 15.3 is consistent with the fluctuation of fractional acceleration gain model.(2) For the sources with nearly same lg ν_p, a significant correlation between the effective spectral indexαroand curvature is detected, while the effective spectral index αoxis not associated with curvature. According to the effective spectral index αro, a correlation between synchrotron peak frequency and curvature can be found.