论文标题
TXS 0128+554：带有情节喷射活动的年轻伽马射线发射AGN
TXS 0128+554: A Young Gamma-Ray Emitting AGN With Episodic Jet Activity
论文作者
论文摘要
我们已经对AGN TXS 0128+554进行了Chandra X射线和多频无线电VLBA研究，该研究与Fermi Gamma-ray源4FGL J0131.2+5547相关。 AGN在19.3 KS Chandra图像中未解决，其光谱非常适合简单的吸收功率定律模型，没有明显的光谱特征。与其他CSO相比，其相对较软的X射线光谱可能表明了热发射成分，为此，我们能够获得Kt = 0.08 KeV的高温极限。紧凑型无线电形态和测量的提前速度为0.32C +-0.07c，表明运动年龄仅为82 y +-17 y，将TXS 0128 +554放置在紧凑型对象（CSO）类的最年轻成员中。缺乏紧凑的，倒置的频谱热点以及明亮的内射流和外部无线电叶结构之间的发射缝隙表明喷气机具有发作性活动，并在十年前重新启动。基于反向康普顿的茧模型，裂片的预测伽马射线发射比观察到的费米LAT通量低三个数量级。与其他经Fermi检测和非Fermi检测到的具有红移Z <0.1的CSO的比较表明，伽马射线发射可能起源于内射流/核心区域，而附近的最近发射的AGN Jets是Fermi LAT仪器检测的主要候选者。
We have carried out a Chandra X-ray and multi-frequency radio VLBA study of the AGN TXS 0128+554, which is associated with the Fermi gamma-ray source 4FGL J0131.2+5547. The AGN is unresolved in a target 19.3 ks Chandra image, and its spectrum is well fit by a simple absorbed power law model, with no distinguishable spectral features. Its relatively soft X-ray spectrum compared to other CSOs may be indicative of a thermal emission component, for which we were able to obtain an upper temperature limit of kT = 0.08 keV. The compact radio morphology and measured advance speed of 0.32c +- 0.07c indicate a kinematic age of only 82 y +- 17 y, placing TXS 0128+554 among the youngest members of the compact symmetric object (CSO) class. The lack of compact, inverted spectrum hotspots and an emission gap between the bright inner jet and outer radio lobe structure indicate that the jets have undergone episodic activity, and were re-launched a decade ago. The predicted gamma-ray emission from the lobes, based on an inverse Compton-emitting cocoon model, is three orders of magnitude below the observed Fermi LAT flux. A comparison to other Fermi-detected and non-Fermi detected CSOs with redshift z<0.1 indicates that the gamma-ray emission likely originates in the inner jet/core region, and that nearby, recently launched AGN jets are primary candidates for detection by the Fermi LAT instrument.
