论文标题
在高架TEV伽玛射线状态下，Blazar VER J0521+211的多波长度观测
Multiwavelength Observations of the Blazar VER J0521+211 During an Elevated TeV Gamma-Ray State
论文作者
论文摘要
我们报告了2013年和2014年，Veritas，Magic和Fermi-Lat观察到的VER J0521+211的持久，升高的伽马射线通量状态。 \; \ text {ph} \; \ text {m}^{ - 2} \;; \ text {s}^{ - 1} $，或crab nebula通量的37％。还提出了来自X射线，紫外线和光学仪器的多波长观测值。观察到X射线和TEV伽马射线通量之间的中等相关性，当通量较高时，X射线频谱似乎更加困难。使用伽马射线频谱和四个模型的外层次背景光（EBL），发现源红移的保守95％置信度上限为z <= 0.31。与伽马射线和X射线频带不同，与档案低状态通量相比，在研究期间，光通量没有显着增加。从光学到X射线带的光谱变异性表明，光谱能分布（SED）的同步峰可能会在耀斑的状态下变得更宽，可以通过单区域同步自compton模型对此进行充分描述，从而改变了下层颗粒光谱的高能量端。 SED的同步加速器峰频率以及Mojave程序的射流的无线电形态与源是一个中间频率的BL LAC对象。
We report on a long-lasting, elevated gamma-ray flux state from VER J0521+211 observed by VERITAS, MAGIC, and Fermi-LAT in 2013 and 2014. The peak integral flux above 200 GeV measured with the nightly-binned light curve is $(8.8 \pm 0.4) \times 10^{-7} \;\text{ph}\;\text{m}^{-2}\; \text{s}^{-1}$, or ~37% of the Crab Nebula flux. Multiwavelength observations from X-ray, UV, and optical instruments are also presented. A moderate correlation between the X-ray and TeV gamma-ray fluxes was observed, and the X-ray spectrum appeared harder when the flux was higher. Using the gamma-ray spectrum and four models of the extragalactic background light (EBL), a conservative 95% confidence upper limit on the redshift of the source was found to be z<=0.31. Unlike the gamma-ray and X-ray bands, the optical flux did not increase significantly during the studied period compared to the archival low-state flux. The spectral variability from optical to X-ray bands suggests that the synchrotron peak of the spectral energy distribution (SED) may become broader during flaring states, which can be adequately described with a one-zone synchrotron self-Compton model varying the high-energy end of the underlying particle spectrum. The synchrotron peak frequency of the SED, as well as the radio morphology of the jet from the MOJAVE program, are consistent with the source being an intermediate-frequency-peaked BL Lac object.
