A population of galaxy-scale jets discovered using LOFAR
A population of galaxy-scale jets discovered using LOFAR
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DOI：
10.1093/mnras/staa3437
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发表时间：
2020-11
影响因子：
4.8
通讯作者：
B. Webster;J. Croston;B. Mingo;R. D. Baldi;B. Barkus;G. Gurkan;M. Hardcastle;R. Morganti;
中科院分区：
文献类型：
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作者：
B. Webster;J. Croston;B. Mingo;R. D. Baldi;B. Barkus;G. Gurkan;M. Hardcastle;R. Morganti;
高光度射电声活动星系核(AGN)的反馈效应已在文献中得到了广泛的讨论，但对低光度射电声活动星系核(AGN)的反馈却知之甚少。像LOFAR这样的高灵敏度、高角度分辨率、大视场望远镜的出现，现在第一次使对这种微弱光源的广域研究成为可能。利用LOFAR两米巡天首次发布的数据，我们报告了我们发现的195个射电星系群，它们的150 MHz光度在3×1022到1.5×1025WHZ−1之间，射电总辐射不超过80kpC。这些天体，我们称之为星系尺度的喷流(GSJ)，小到足以直接影响星系尺度上的宿主的演化。我们报告了样本的典型宿主属性，发现9%由螺旋星系托管，其余的由椭圆星系托管。其中两个螺旋托管的GSJ非常不寻常，射电亮度很低，形态类似FRII。我们的GSJ的宿主属性表明，它们是在射电发射扩展到宿主中心区域之外后不久生命中的一个阶段观察到的普通活动星系核。根据我们的估计，我们发现大约有一半的GSJ的内部射电叶能量在ISM能量的数量级内，因此，即使忽略任何可能的冲击，GSJ也能够从能量上影响宿主的演化。目前的GSJ样本将随着LoTSS的未来发布而扩大，也可以成为进一步研究来自低光度射电源的反馈的基础。
The effects of feedback from high luminosity radio-loud active galactic nuclei (AGN) have been extensively discussed in the literature, but feedback from low-luminosity radio-loud AGN is less well understood. The advent of high sensitivity, high angular resolution, large field-of-view telescopes such as LOFAR is now allowing wide-area studies of such faint sources for the first time. Using the first data release of the LOFAR Two Metre Sky Survey (LoTSS) we report on our discovery of a population of 195 radio galaxies with 150-MHz luminosities between 3 × 1022 and 1.5 × 1025 WHz−1 and total radio emission no larger than 80 kpc. These objects, which we term galaxy-scale jets (GSJ), are small enough to be directly influencing the evolution of the host on galaxy scales. We report upon the typical host properties of our sample, finding that 9 per cent are hosted by spirals with the remainder being hosted by elliptical galaxies. Two of the spiral-hosted GSJ are highly unusual with low radio luminosities and FRII-like morphology. The host properties of our GSJ show that they are ordinary AGN observed at a stage in their life shortly after the radio emission has expanded beyond the central regions of the host. Based on our estimates, we find that about half of our GSJ have internal radio lobe energy within an order of magnitude of the ISM energy so that, even ignoring any possible shocks, GSJ are energetically capable of affecting the evolution of the host. The current sample of GSJ will grow in size with future releases of LoTSS and can also form the basis for further studies of feedback from low-luminosity radio sources.