蝎虎类星体Mrk 421的宽带能谱光变特性分析

Analyzing the Variations in the Spectral Energy Distribution of the BL Lac Object Mrk 421

搜集了Mrk 421的光变宽带光谱能量分布(Spectral Energy Distributions,SEDs)数据,共有73个态作为研究样本,使用电子能谱为稳态拐折幂律谱的单区轻子模型进行拟合,进而研究Mrk 421在光变时喷流的物理性质。主要结果如下:(1)样本中磁场B和多普勒因子δ之间显著反相关,说明B和δ在汤姆逊(Thomson)区相互依赖。(2)电子谱指数p_(1)支持Mrk 421光变时的激波解释或磁重联等解释。(3)同步峰值频率logν^(pk)_(syn)和峰值光度logν^(pk)_(syn)L^(pk)_(syn)之间存在正相关关系,意味着Mrk 421在光变时存在反耀变体序列。(4)根据均分参数ε=U_(e)/U_(B)(相对论电子能量密度与磁场能量密度的比值),有26%的态电子能量和磁场能量接近均分,63%的态电子能量比磁场能量大一个数量级,11%的态电子能量远大于磁场能量,这说明Mrk 421在光变过程中更可能出现电子能量比磁场能量大一个数量级的情况,同时也意味着Mrk 421中的喷流是以粒子为主导;P_(e)>P_(B)的关系进一步表明Mrk 421的喷流是以粒子为主导,P_(B)P_(r)意味着坡印廷通量不能解释辐射功率,P_(r)/P_(e)的范围为0.01~0.51,说明相对论电子能量中的一小部分可能用于观测到的辐射。(5)3C 279和Mrk 421的一些物理参数范围可能比较接近,但这两个源喷流内的物理过程可能是不一样的。

The spectral energy distributions(SEDs)datas of Mrk 421 are collected,totally 73 states as research samples.The single-region lepton model under the electron energy spectrum of the steady-state transition power law spectrum is applied.Then the physical properties of Mrk 421 jets during the light transition is studied.Our main results are as follows:(1)There is an anticorrelation between magnetic B and Dopplerδin the sample,indicating that magnetic B and Dopplerδare interdependent in the Thomson region.(2)Electron spectral index p 1 supports the interpretation of shock wave or magnetic reconnection during light variation of Mrk 421.(3)There is a positive correlation between the synchronous peak frequency logν^(pk)_(syn)and the peak luminosity logν^(pk)_(syn)L^(pk)_(syn),which means that there is an anti-flare variant sequence in the Mrk 421 during the light change.(4)According to the equal partition parameterε=U_(e)/U_(B)(the ratio of relativistic electron energy density to magnetic field energy density),the electron energy and magnetic field energy of 26%of the states are nearly equal partition,the electron energy of 63%of the states is an order of magnitude larger than the magnetic field energy,the electron energy of 11%of the states is much larger than the magnetic field energy.This indicates that Mrk 421 is more likely to have the phenomenon that the electron energy is one order of magnitude larger than the magnetic field energy during the light change.It also means that the jets in the Mrk 421 are dominated by particles;From the relationship of P_(e)>P_(B),it is further shown that the Mrk 421 jets are particle-dominated,P_(B)≥P_(r),meaning that the Poynting flux cannot account for the radiated power;The ranges of P_(r)/P_(e)from 0.01 to 0.51,show that a small fraction of the relativistic electron energy may be used for the observed radiation.(5)Some ranges of the physical parameters of 3C 279 and Mrk 421 may be relatively similar,but the physical processes inside the jets of these two sources may not be the same.