TeV耀变体在光学和γ射线波段的相关性研究

Correlation Study of TeV Blazars in Optical Band and γ-ray Band

多波段相关性分析对研究耀变体(Blazar)的物理模型和辐射机制具有重要意义。为了研究TeV耀变体的物理模型,依据4FGL-DR3目录中78个TeV耀变体的对应体的名称及坐标,对他们的γ射线波段数据和光学波段数据进行了搜索和整理,发现同时具有光学波段和γ射线波段数据的TeV耀变体共56个。利用离散相关函数计算每个耀变体光学和γ射线的相关性,计算结果显示,有20个源表现出弱的γ射线-光学相关性,有30个源表现出强的γ射线-光学相关性,有6个源没有表现出相关性。在表现出强相关性的源中,光学波段和γ射线波段间还表现出不同程度的时间延迟。这些结果支持了TeV耀变体高能光子主要来自轻子模型的同步自康普顿辐射。但是同时还发现不管是光学波段还是γ射线波段,均存在一些“孤峰”,这些“孤峰”可能暗示了低能光子的来源不是唯一的。

Multi band correlation analysis is of great significance to the study of the physical model and radiation mechanism of Blazars.In order to study the physical model of TeV Blazars,we search and sort out their γ-ray band data and optical band data according to the names and coordinates of their counterparts of 78 TeV Blazars in the 4FGL-DR3 catalogue,and find that there are 56 TeV Blazars with both optical band and γ-ray band data.The Discrete Correlation Function(DCF)is used to calculate the correlation between the optics and γ-ray of each Blazar.The calculation results show that 20 sources show weak γ-ray-optical correlation,30 sources show strongγ-ray-optical correlation,and 6 sources show no γ-ray-optical correlation.Among sources that exhibit strong correlation,there is also varying degrees of time delay between the optical and γ-ray bands.These results support that the high-energy photons of TeV Blazar mainly come from synchronous self Compton radiation of lepton model.However,we also find that there are some“orphan flares”in both the optical and γ-ray bands,which may indicate that the source of low energy photons is not unique.