论文标题
通过活动地平线望远镜解决Blazar J1924-2914的内部parsec
Resolving the inner parsec of the blazar J1924-2914 with the Event Horizon Telescope
论文作者
论文摘要
Blazar J1924-2914是银河中心的黑洞射手座A*的主要事件地平线望远镜（EHT）校准器。在这里，我们介绍了以前所未有的20 $μ$作为EHT分辨率获得的该源的第一个总和极化强度图像。 J1924-2914是一种非常紧凑的平发无线电源，具有很强的光学变异性和极化。 2017年4月，与EHT（4月5日至11日），全球毫米VLBI阵列（4月3日）和非常长的基线阵列（4月28日）观察到了源，并以四个观察频率，230，86，86，86，8.7和2.3 GHz提供了新颖的看法。这些观察值探测了从地下到100-PARSEC量表的探测射流性能。我们结合了J1924-2914的多频图像来研究源形态。我们发现该射流具有特征性的弯曲，其射流投影位置角的逐渐顺时针旋转在2.3至230 GHz之间约为90度。 EHT极为精细的J1924-2914的线性极化强度图像为Blazar紧凑型芯中有序的环形磁场提供了证据。
The blazar J1924-2914 is a primary Event Horizon Telescope (EHT) calibrator for the Galactic Center's black hole Sagittarius A*. Here we present the first total and linearly polarized intensity images of this source obtained with the unprecedented 20 $μ$as resolution of the EHT. J1924-2914 is a very compact flat-spectrum radio source with strong optical variability and polarization. In April 2017 the source was observed quasi-simultaneously with the EHT (April 5-11), the Global Millimeter VLBI Array (April 3), and the Very Long Baseline Array (April 28), giving a novel view of the source at four observing frequencies, 230, 86, 8.7, and 2.3 GHz. These observations probe jet properties from the subparsec to 100-parsec scales. We combine the multi-frequency images of J1924-2914 to study the source morphology. We find that the jet exhibits a characteristic bending, with a gradual clockwise rotation of the jet projected position angle of about 90 degrees between 2.3 and 230 GHz. Linearly polarized intensity images of J1924-2914 with the extremely fine resolution of the EHT provide evidence for ordered toroidal magnetic fields in the blazar compact core.
