论文标题

使用混合X射线RADIO方法测量聚类中活性银河核的腔功能 - 由Subarcsond Lofar-vlbi观察结果打开的反馈的新窗口

Measuring cavity powers of active galactic nuclei in clusters using a hybrid X-ray-radio method -- A new window on feedback opened by subarcsecond LOFAR-VLBI observations

论文作者

Timmerman, R., van Weeren, R. J., Botteon, A., Röttgering, H. J. A, McNamara, B. R., Sweijen, F., Bîrzan, L., Morabito, L. K.

论文摘要

活性银河核向聚类环境注入的射模反馈数量的测量主要依赖于X射线观测值,X射线观察结果揭示了无线电裂片发掘的簇内培养基中的空腔。但是,准确限制这些腔的尺寸所需的灵敏度已被证明是一个主要的限制因素,是高红移测量值的主要瓶颈。我们描述了一种基于X射线和无线电观测的组合的混合方法,该方法旨在增强我们研究无线电模式反馈的能力。在本文中,我们介绍了以144 MHz为国际Lofar望远镜(ILT)观察到的第一批星系簇样本之一,并使用此样品在较低的频率下测试混合方法。通过仅使用X射线观察的传统方法,将我们的测量与文献中发现的结果进行比较,我们发现混合方法为传统方法提供了一致的结果。此外,我们发现传统方法与混合方法之间的相关性有所改善,因为X射线腔的定义更加明确。这表明,将无线电裂片用作腔体的代理可能有助于绕过空腔体积测量中的系统不确定性。在成功处理的大量独特的ILT观测值的鼓励下,这种混合方法使无线电模式反馈也可以在高红移中进行研究,即使是大型群集样本。

Measurements of the quantity of radio-mode feedback injected by an active galactic nucleus into the cluster environment have mostly relied on X-ray observations, which reveal cavities in the intracluster medium excavated by the radio lobes. However, the sensitivity required to accurately constrain the dimensions of these cavities has proven to be a major limiting factor and is the main bottleneck on high-redshift measurements. We describe a hybrid method based on a combination of X-ray and radio observations, which aims to enhance our ability to study radio-mode feedback. In this paper, we present one of the first samples of galaxy clusters observed with the International LOFAR Telescope (ILT) at 144 MHz and use this sample to test the hybrid method at lower frequencies than before. By comparing our measurements with results found in literature based on the traditional method using only X-ray observations, we find that the hybrid method provides consistent results to the traditional method. In addition, we find that the correlation between the traditional method and the hybrid method improves as the X-ray cavities are more clearly defined. This suggests that using radio lobes as proxies for cavities may help to circumvent systematic uncertainties in the cavity volume measurements. Encouraged by the high volume of unique ILT observations successfully processed, this hybrid method enables radio-mode feedback to be studied at high redshifts for the first time even for large samples of clusters.

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