New jet feature in the parsec-scale jet of the blazar OJ 287 connected to the 2017 teraelectronvolt flaring activity
New jet feature in the parsec-scale jet of the blazar OJ 287 connected to the 2017 teraelectronvolt flaring activity
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与 2017 年太电子伏特耀斑活动相关的 Blazar OJ 287 秒差距级喷流中的新喷流特征
DOI：
10.1051/0004-6361/202142948
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发表时间：
2022
影响因子：
6.5
通讯作者：
Cho, I.
中科院分区：
文献类型：
--
作者：
Lico, R.;Casadio, C.;Jorstad, S. G.;Gómez, J. L.;Marscher, A. P.;Traianou, E.;Kim, J.-Y.;Zhao, G.-Y.;Fuentes, A.;Cho, I.
背景2017年2月，Blazar OJ 287，最好的超大质量双星黑洞系统候选者之一，首次在甚高能量（VHEs;E> 100 GeV）被地面γ射线天文台VERITAS探测到。目的甚高能量γ射线被认为是在活动星系核的中央引擎附近产生的。 出于这个原因，并与提供有用的信息，与观测到的太电子伏耀斑事件的物理机制的特性的主要目标，利用86 GHz全球毫米波VLBI阵列（GMVA）观测资料，利用高分辨率甚长基线干涉仪观测资料，研究了秒差距尺度的源特性。观测2015年至2017年，并结合联合收割机在其他监测计划在不同频率的额外多波长无线电观测。我们调查的源结构，通过建模的亮度分布与二维高斯分量在visibility plane.ResultsIn GMVA时代的源VHE活动后，我们发现一个新的射流功能（标记K）在<$0.2 mas从核心区域和位于两个准静态组件（标记S1和S2）之间。在VHE燃烧状态之前和期间，在不同的无线电频率下检测到多个增强的活动周期。我们认为，在2017年的前几个月里，一种新的喷流特征通过一个再准直激波，可能是VHE燃烧排放的触发因素（由模型拟合分量S1表示）位于距无线电核心的去投影距离为1000 pc的射流区域中。
ContextIn February 2017 the blazar OJ 287, one of the best super-massive binary-black-hole-system candidates, was detected for the first time at very high energies (VHEs;E> 100 GeV) with the ground-basedγ-ray observatory VERITAS.AimsVery high energyγrays are thought to be produced in the near vicinity of the central engine in active galactic nuclei. For this reason, and with the main goal of providing useful information for the characterization of the physical mechanisms connected with the observed teraelectronvolt flaring event, we investigate the parsec-scale source properties by means of high-resolution very long baseline interferometry observations.MethodsWe use 86 GHz Global Millimeter-VLBI Array (GMVA) observations from 2015 to 2017 and combine them with additional multiwavelength radio observations at different frequencies from other monitoring programs. We investigate the source structure by modeling the brightness distribution with two-dimensional Gaussian components in the visibility plane.ResultsIn the GMVA epoch following the source VHE activity, we find a new jet feature (labeled K) at ∼0.2 mas from the core region and located in between two quasi-stationary components (labeled S1 and S2). Multiple periods of enhanced activity are detected at different radio frequencies before and during the VHE flaring state.ConclusionsBased on the findings of this work, we identify as a possible trigger for the VHE flaring emission during the early months of 2017 the passage of a new jet feature through a recollimation shock (represented by the model-fit component S1) in a region of the jet located at a de-projected distance of ∼10 pc from the radio core.