费米耀变体光学波段色指数变化的研究

Study on Color Index of the Fermi Blazars

利用调整流量基准面的方法修正19个费米耀变体(Blazars)的光学波段流量与色指数,通过对比修正前后色指数与星等的相关关系,研究多普勒因子对色指数变化机制的影响。研究表明:(1)修正前,只有5个源呈现明显的颜色变蓝的趋势,2个源呈现明显的颜色变红的趋势;(2)修正后,有9个源呈现明显的颜色变蓝的趋势,6个源呈现弱的颜色变蓝的趋势,只有4个源的色指数与星等不存在相关关系;(3)大约有一半的源的色变机制受多普勒聚束效应的影响,修正后,这些源的色指数与星等的相关性增强;(4)多普勒因子的变化可能是造成颜色变蓝的趋势变弱的原因。通过研究色指数和星等的相关关系,能进一步解释耀变体的辐射机制。

In this paper,the optical bandflux and color index of 19 Fermi Blazars are corrected by modulating the flux base-level.By comparing the correlation between the color index and the magnitude before and after the correction,the effect of the Doppler factor on the color index change mechanism is studied.Studies show that:(1)only five sources show a clear BWB trend before the correction,and two sources show a clear RWB trend;(2)after the correction,nine sources show a clear BWB trend,and six sources show a weak BWB trend,only the color indices of 4 sources have no correlation with the magnitude;(3)The color change mechanism of about half of the sources is affected by the Doppler beamforming effect.After correction,the correlation between the color index and magnitude of these sources is enhanced;(4)The change of the Doppler factor may be the cause of the weakening of the BWB trend.By studying the correlation between the color index and the magnitude,the radiation mechanism of Blazars can be further explained.