The PG-RQS survey. Building the radio spectral distribution of radio-quiet quasars. I. The 45-GHz data
The PG-RQS survey. Building the radio spectral distribution of radio-quiet quasars. I. The 45-GHz data
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PG-RQS 调查。
DOI：
10.1093/mnras/stab3445
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发表时间：
2022
影响因子：
4.8
通讯作者：
Baldi R
中科院分区：
文献类型：
--
作者：
Baldi R
射电宁静类星体（RQQs）中射电辐射的起源仍然不清楚。射电辐射可能是由射电响（RL）活动星系核中观测到的相对论喷流的缩小版本、活动星系核驱动的风、吸积盘日冕、活动星系核周围气体的光子电离（自由-自由辐射）或星星形成（SF）产生的。在这里，我们报告了一个试点研究，无线电调查（'PG-RQS'）的一部分，旨在探索71帕洛玛-格林（PG）RQS的光谱分布：高角分辨率观测（1050 mas）在45 GHz（7 mm）的卡尔G。Jansky非常大的阵列15个来源。在13个源中检测到的亚mJy射电核心的典型尺度为1000 pc，这排除了星系尺度SF的重要贡献。对于9个源，45-GHz的光度高于较低频率（101 -10 GHz）的光谱外推，表明在高频出现了额外的平坦光谱紧凑的组件。X射线光度和黑洞（BH）质量与45 GHz光度的相关性比5 GHz更紧密。基于45 GHz的无线电响度随着爱丁顿比的减小和BH质量MBH的增加而增加。这些结果表明，45-GHz的发射从PG RQQQ核起源于核心的最里面的区域，可能来自吸积盘日冕。越来越多的贡献，45 GHz的发射从射流在higherMBHand较低的爱丁顿比和从盘风在大的爱丁顿比仍然与我们的结果是一致的。未来对样品的全无线电光谱覆盖将有助于我们研究RQQ核心中不同的物理机制。
The origin of the radio emission in radio-quiet quasars (RQQs) remains unclear. Radio emission may be produced by a scaled-down version of the relativistic jets observed in radio-loud (RL) AGN, an AGN-driven wind, the accretion disc corona, AGN photon-ionization of ambient gas (free–free emission), or star formation (SF). Here, we report a pilot study, part of a radio survey (‘PG-RQS’) aiming at exploring the spectral distributions of the 71 Palomar–Green (PG) RQQs: high angular resolution observations (∼50 mas) at 45 GHz (7 mm) with the Karl G. Jansky Very Large Array of 15 sources. Sub-mJy radio cores are detected in 13 sources on a typical scale of ∼100 pc, which excludes significant contribution from galaxy-scale SF. For 9 sources the 45-GHz luminosity is above the lower frequency (∼1–10 GHz) spectral extrapolation, indicating the emergence of an additional flatter-spectrum compact component at high frequencies. The X-ray luminosity and black hole (BH) mass, correlate more tightly with the 45-GHz luminosity than the 5-GHz. The 45 GHz-based radio-loudness increases with decreasing Eddington ratio and increasing BH massMBH. These results suggest that the 45-GHz emission from PG RQQs nuclei originates from the innermost region of the core, probably from the accretion disc corona. Increasing contributions to 45-GHz emission from a jet at higherMBHand lower Eddington ratios and from a disc wind at large Eddington ratios are still consistent with our results. Future full radio spectral coverage of the sample will help us investigating the different physical mechanisms in place in RQQ cores.