论文标题
$γ$ -Ray窄线Seyfert 1 Galaxy SDSS J211852.96 $ - $ 073227.5的无线电结构
The radio structure of the $γ$-ray narrow-line Seyfert 1 galaxy SDSS J211852.96$-$073227.5
论文作者
论文摘要
$γ$ -Ray窄线seyfert 1（NLS1）星系可以被认为是具有相对论喷射的$γ$ ray活性银河核的第三类。在本文中，我们介绍了$γ$ -Ray nls1，SDSS J211852.96 $ - $ 073227.5（j2118 $ - $ 0732，$ z = 0.26 $）的多波段高分辨率非常长的基线阵列（VLBA）图像。我们发现无线电芯中的核心喷射无线电形态和显着的通量密度变化。 VLBA图像和核心变异性估计的高亮度温度表明，它表现出很大的相对论射线效应。从考虑几个频段的无线电发射，我们发现源具有以上1 GHz以上的倒置频谱，但是在从74 MHz到1 GHz的低频下陡峭的频谱；这些可能分别来自当前活动和旧的弥散/扩展发射。核心形态，明显的磁通密度变化和光束效果使J2118 $ - $ 0732类似于大黄花。考虑到其中央黑洞和正在进行的合并环境的低质量，J2118 $ - $ 0732可能代表了大型质量，低功率的对应物，并最终可能演变为Blazar。
The $γ$-ray narrow-line Seyfert 1 (NLS1) galaxies can be considered to be the third class of $γ$-ray active galactic nuclei possessing relativistic jets. In this paper, we present multi-band high resolution Very Long Baseline Array (VLBA) images of the $γ$-ray NLS1, SDSS J211852.96$-$073227.5 (J2118$-$0732, $z=0.26$). We find a core-jet radio morphology and significant flux density variations in the radio core. The high brightness temperature estimated from VLBA images and core variability demonstrate that it exhibits substantial relativistic beaming effects. From considering radio emission in several bands, we find that the source has an inverted spectrum above 1 GHz but a steep spectrum at low frequencies from 74 MHz to 1 GHz; these may arise from the present activity and the old diffuse/extended emission, respectively. The core-jet morphology, significant flux density variations, and beaming effect make J2118$-$0732 resemble a blazar. Considering the low mass of its central black hole and ongoing merger environment, J2118$-$0732 may represent a low-mass, low-power counterpart of blazars, and may finally evolve to a blazar.
