The variability of brightest cluster galaxies at high radio frequencies
The variability of brightest cluster galaxies at high radio frequencies
复制标题
高射频下最亮星团星系的变化
DOI：
10.1093/mnras/stab3217
复制
发表时间：
2021
影响因子：
6.5
通讯作者：
A. Sedgewick
中科院分区：
文献类型：
--
作者：
T. Rose;A. Edge;S. Kiehlmann;J. Baek;A. Chung;T. Jung;Jae;A. Readhead;A. Sedgewick
星系核心射电源的变化可能是活动星系核吸积的重要结果。然而，这种变化还没有得到很好的研究，特别是在高无线电频率。因此，我们报告了一项监测附近20个冷核最亮星系团的高无线电频率变化的活动。从我们的代表性样本中，我们发现大多数在大约一年或更长的时间尺度上变化很大。我们的最高频率观测是在15 GHz，来自欧文斯谷射电天文台（OVRO）。它们的平均时间间隔为7天，大多数跨度为8至13年。我们应用一系列的变化检测技术的来源的光变曲线，以分析变化的一周到十年的时间尺度。最值得注意的是，至少有一半的来源显示，在3年的时间尺度上，峰谷变化率为20%，而在6年的时间尺度上，至少有三分之一的变化率为60%。显著的变化，这是重要的研究的Sunyaev-Zel'dovich效应在无线电/亚毫米，因此，这些来源的一个共同特点。我们还展示了如何变化与光谱特性在频率高达353 GHz的韩国VLBI网络（KVN），NIKA 2仪器的IRAM 30米望远镜，和SCUBA-2仪器的詹姆斯·克拉克麦克斯韦望远镜的数据。
Variability of a galaxy's core radio source can be a significant consequence of AGN accretion. However, this variability has not been well studied, particularly at high radio frequencies. As such, we report on a campaign monitoring the high radio frequency variability of 20 nearby, cool-core brightest cluster galaxies. From our representative sample, we show that most vary significantly over timescales of approximately one year and longer. Our highest cadence observations are at 15 GHz and are from the Owens Valley Radio Observatory (OVRO). They have a median time interval of 7 days and mostly span between 8 and 13 years. We apply a range of variability detection techniques to the sources' lightcurves to analyse changes on week to decade long timescales. Most notably, at least half of the sources show 20 per cent peak to trough variability on 3 year timescales, while at least a third vary by 60 per cent on 6 year timescales. Significant variability, which is important to studies of the Sunyaev-Zel'dovich Effect in the radio/sub-mm, is therefore a common feature of these sources. We also show how the variability relates to spectral properties at frequencies of up to 353 GHz using data from the Korean VLBI network (KVN), the NIKA2 instrument of the IRAM 30m telescope, and the SCUBA-2 instrument of the James Clerk Maxwell Telescope.