MIGHTEE: deep 1.4 GHz source counts and the sky temperature contribution of star-forming galaxies and active galactic nuclei
MIGHTEE: deep 1.4 GHz source counts and the sky temperature contribution of star-forming galaxies and active galactic nuclei
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MIGHTEE：深 1.4 GHz 源计数以及恒星形成星系和活动星系核对天空温度的贡献
DOI：
10.1093/mnras/stac3320
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发表时间：
2023
影响因子：
4.8
通讯作者：
Hale C
中科院分区：
文献类型：
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作者：
Hale C
我们提出了深1.4 GHz源计数从1.5 deg 2的连续早期科学数据发布的MeerKAT国际千兆赫分层河外探测调查下降到S1.4 GHz的1.15 Jy。使用两个河外领域（COSMOS和XMM-LSS）的观测，我们提供了一个全面的调查，以纠正调查中的原始源计数的不完整性，以了解真正的底层源计数人口。我们使用各种模拟占：源检测和表征，聚类，并在假设的源模型用于模拟源内的字段和表征源计数不完整性的错误。我们提出了这些深源计数分布，并使用它们来调查银河系外源的贡献，天空背景温度在1.4 GHz使用一个相对较大的天空面积。然后，我们使用丰富的辅助数据覆盖的COSMOS领域的一个子集，调查活动星系核（AGN）和恒星形成星系（SFGs）的源计数和天空背景温度的具体贡献。我们发现，与以前的深入研究类似，我们无法调和ARCADE 2实验观察到的天空温度。我们发现活动星系核对射电源对天空温度的贡献占大多数，但SFG的相对贡献在1 mJy以下急剧上升，在15 Jy时对天空总背景温度（Tb = 100 mK）的贡献约为15%-25%。
We present deep 1.4 GHz source counts from ∼5 deg2of the continuum Early Science data release of the MeerKAT International Gigahertz Tiered Extragalactic Exploration survey down toS1.4GHz∼15Jy. Using observations over two extragalactic fields (COSMOS and XMM-LSS), we provide a comprehensive investigation into correcting the incompleteness of the raw source counts within the survey to understand the true underlying source count population. We use a variety of simulations that account for: errors in source detection and characterization, clustering, and variations in the assumed source model used to simulate sources within the field and characterize source count incompleteness. We present these deep source count distributions and use them to investigate the contribution of extragalactic sources to the sky background temperature at 1.4 GHz using a relatively large sky area. We then use the wealth of ancillary data covering a subset of the COSMOS field to investigate the specific contributions from both active galactic nuclei (AGN) and star-forming galaxies (SFGs) to the source counts and sky background temperature. We find, similar to previous deep studies, that we are unable to reconcile the sky temperature observed by the ARCADE 2 experiment. We show that AGN provide the majority contribution to the sky temperature contribution from radio sources, but the relative contribution of SFGs rises sharply below 1 mJy, reaching an approximate 15–25 per cent contribution to the total sky background temperature (Tb∼100 mK) at ∼15Jy.