论文标题
重力镜头伽马射线Blazar JVAS B0218+357的毫米VLBI检测和成像
Millimeter-VLBI Detection and Imaging of the Gravitationally Lensed Gamma-Ray Blazar JVAS B0218+357
论文作者
论文摘要
我们在22、43和86 GHz的KVN和Vera阵列（KAVA）中观察到重力镜头Blazar JVAS B0218+357。该源最近被确定为GEV/TEV能量带的活动伽马射线源，从而为通过重力镜头研究提供了相对论喷射的独特目标。在这里，我们报告了最高86 GHz的镜头图像的第一个强大的VLBI检测和成像。单个镜头图像（A和B）的检测到的MAS规模/PARSEC尺度形态与先前在22和15 GHz处看到的MAS尺度/尺度的形态（A和B）一致，显示了与低频处的射流方向相同的核心形态。镜头图像的无线电光谱能分布在较高的频率下变得更加陡峭，表明最内向的喷气区域在光学上变薄而对同步加速器发射。我们的发现证实，在毫米波长下，由于中间的透镜星系引起的吸收效应可忽略不计。这些结果表明，高频VLBI观测是一种强大的工具，可以更好地恢复镜头活性银河核喷气机的内在特性，因此使我们能够研究低能和高能发射之间的相互作用。
We observed the gravitationally lensed blazar JVAS B0218+357 with the KVN and VERA Array (KaVA) at 22, 43, and 86 GHz. The source has recently been identified as an active gamma-ray source up to GeV/TeV energy bands, rendering a unique target for studying relativistic jets through gravitational lensing. Here we report the first robust VLBI detection and imaging of the lensed images up to 86 GHz. The detected mas-scale/parsec-scale morphology of the individual lensed images (A and B) is consistent with that previously seen at 22 and 15 GHz, showing the core-jet morphology with the jet direction being the same as at the low frequencies. The radio spectral energy distributions of the lensed images become steeper at higher frequencies, indicating that the innermost jet regions become optically thin to synchrotron emission. Our findings confirm that the absorption effects due to the intervening lensing galaxy become negligible at millimeter wavelengths. These results indicate that high-frequency VLBI observations are a powerful tool to better recover the intrinsic properties of lensed active galactic nucleus jets, which therefore allow us to study the interplay between the low- and high-energy emission.
