High-resolution imaging with the International LOFAR Telescope: Observations of the gravitational lenses MG 0751+2716 and CLASS B1600+434
High-resolution imaging with the International LOFAR Telescope: Observations of the gravitational lenses MG 0751+2716 and CLASS B1600+434
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使用国际 LOFAR 望远镜进行高分辨率成像：引力透镜 MG 0751 2716 和 CLASS B1600 434 的观测
DOI：
10.1051/0004-6361/202141227
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发表时间：
2022
影响因子：
6.5
通讯作者：
Badole S
中科院分区：
文献类型：
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作者：
Badole S
我们介绍了低频阵列（LOFAR）望远镜对射电大声引力透镜系统MG 0751+2716和CLASS B1600+434的观测结果。这些观测在150兆赫下产生300毫弧秒（mas）分辨率的图像。在MG 0751+2716的情况下，透镜模型用于得出低频源的尺寸估计约为2kpc，这与之前由karl G. JanskyVery Large Array在无线电连续体中进行的27.4 GHz研究一致。这种一致性意味着低频射电源与形成高频射电结构的核心射流结构是共空间的，并且在透镜的放大区域内没有检测到显著的瓣发射或与恒星形成相关的进一步成分。CLASS B1600+434是一个双像透镜，其中一个图像穿过边缘上的螺旋透镜星系，低射频使我们能够得出透镜星系中传播效应的限制，即散射。在观测频率为150 MHz时，两幅透镜图像的磁通密度比为1.19±0.04。在假设图像a不受散射影响的情况下，两幅图像在星系平面上方约1 kpc处的积分散射柱上的宽度上限为0.035 kpc m−20∕3。这是相对较小的限制，通过非常长的基线干涉测量研究，在透镜系统的微分散射。这些观测结果表明，LOFAR是研究引力透镜的绝佳仪器。我们还报告了无法校准三个进一步的透镜观测：两个来自早期观测，没有很好地确定台站校准，第三个观测受到相位转移问题的影响。
We present Low-Frequency Array (LOFAR) telescope observations of the radio-loud gravitational lens systems MG 0751+2716 and CLASS B1600+434. These observations produce images at 300 milliarcseconds (mas) resolution at 150 MHz. In the case of MG 0751+2716, lens modelling is used to derive a size estimate of around 2 kpc for the low-frequency source, which is consistent with a previous 27.4 GHz study in the radio continuum withKarl G. JanskyVery Large Array. This consistency implies that the low-frequency radio source is cospatial with the core-jet structure that forms the radio structure at higher frequencies, and no significant lobe emission or further components associated with star formation are detected within the magnified region of the lens. CLASS B1600+434 is a two-image lens where one of the images passes through the edge-on spiral lensing galaxy, and the low radio frequency allows us to derive limits on propagation effects, namely scattering, in the lensing galaxy. The observed flux density ratio of the two lensed images is 1.19 ± 0.04 at an observed frequency of 150 MHz. The widths of the two images give an upper limit of 0.035 kpc m−20∕3on the integrated scattering column through the galaxy at a distance approximately 1 kpc above its plane, under the assumption that image A is not affected by scattering. This is relatively small compared to limits derived through very long baseline interferometry studies of differential scattering in lens systems. These observations demonstrate that LOFAR is an excellent instrument for studying gravitational lenses. We also report on the inability to calibrate three further lens observations: two from early observations that have less well determined station calibration, and a third observation impacted by phase transfer problems.