论文标题
Hetdex中星系簇的Lofar观察结果
LOFAR observations of galaxy clusters in HETDEX
论文作者
论文摘要
以无线电光环和文物的形式进行弥散的簇无线电来源揭示了集群内培养基（ICM）中的宇宙射线和磁场的存在。这些宇宙射线被认为是通过集群合并事件产生的ICM湍流和冲击波加速的（重新）。在这里，我们表征了Hetdex弹簧场中已知的Galaxy群集中弥漫性无线电发射的存在，覆盖了424度$^2 $。为此，我们开发了一种方法，可以从与批次DDF-Pipeline处理的Lofar观测值中提取单个目标。该过程可以改善所选目标多个点的校准和关节成像和反卷积。校准策略也可用于Lofar低频天线（LBA）和国际基线观测。 Planck PSZ2群集的比例与ICM显然相关的任何弥漫性无线电排放量为$ 73 \ pm17 \％$。我们在Hetdex弹簧场中总共检测到10个无线电光环和12个候选光晕。五个集群主机无线电文物。 Planck PSZ2群集中的无线电晕部为$ 31 \ pm11 \％$，$ 62 \ pm15 \％$在包括候选无线电晕圈时。基于这些数字，我们预计与预测一致的PSZ2群集的Lots调查中至少会有至少$ 183 \ pm 65 $的无线电光照。通过将指数模型拟合到无线电图像来计算无线电光环的集成通量密度。从这些磁通密度中，我们确定簇质量（M $ _ {500} $）和Compton y参数（y $ _ {500} $）150 MHz无线电电源（P $ _ {\ rm {150 MHz}} $）缩放PLANCK PSZ2-DETECTED RADITID RADITED RADITID RADIO halos的缩放关系。我们发现，这些关系的斜率比从1.4 GHz无线电力量确定的斜率陡峭。但是，考虑到不确定性，这并不是统计学上的重要结果。
Diffuse cluster radio sources, in the form of radio halos and relics, reveal the presence of cosmic rays and magnetic fields in the intracluster medium (ICM). These cosmic rays are thought to be (re-)accelerated through ICM turbulence and shock waves generated by cluster merger events. Here we characterize the presence of diffuse radio emission in known galaxy clusters in the HETDEX Spring Field, covering 424 deg$^2$. For this, we developed a method to extract individual targets from LOFAR observations processed with the LoTSS DDF-pipeline. This procedure enables improved calibration and joint imaging and deconvolution of multiple pointings of selected targets. The calibration strategy can also be used for LOFAR Low-Band Antenna (LBA) and international-baseline observations. The fraction of Planck PSZ2 clusters with any diffuse radio emission apparently associated with the ICM is $73\pm17\%$. We detect a total of 10 radio halos and 12 candidate halos in the HETDEX Spring Field. Five clusters host radio relics. The fraction of radio halos in Planck PSZ2 clusters is $31\pm11\%$, and $62\pm15\%$ when including the candidate radio halos. Based on these numbers, we expect that there will be at least $183 \pm 65$ radio halos found in the LoTSS survey in PSZ2 clusters, in agreement with predictions. The integrated flux densities for the radio halos were computed by fitting exponential models to the radio images. From these flux densities, we determine the cluster mass (M$_{500}$) and Compton Y parameter (Y$_{500}$) 150 MHz radio power (P$_{\rm{150 MHz}}$) scaling relations for Planck PSZ2-detected radio halos. We find that the slopes of these relations are steeper than those determined from the 1.4 GHz radio powers. However, considering the uncertainties this is not a statistically significant result.
