论文标题
通过在43和86 GHz的KAVA和KVN的3C 84核中自由吸收对环核盘的约束。
Constraints on Circumnuclear Disk through Free-Free Absorption in the Nucleus of 3C 84 with KaVA and KVN at 43 and 86 GHz
论文作者
论文摘要
珀尔修斯集群中心的附近明亮的射电星系3C 84是探索活性银河核（AGNS）及其parsec尺度环境中射流的理想目标之一。最近对Fujita＆Nagai的研究揭示了北部反喷射组件（N1）的存在，位于$ \ sim $ \ sim $ 2 MAS $ 2 MAS北部的VLBI图像中的15和43 GHz中的中心核心北部，由于离子化的血浆前景而引起的免费免费吸收（FFA）。在这里，我们报告了2016年2月2016年的43 GHz，在86 GHz的韩国VLBI网络（KVN）和KVN和Vera（VLBI探索）阵列（VLBI探索）中，对3C 84进行了新的准单词观察。我们在86 GHz接替了N1的首次检测，数据表明，N1仍然具有43至86 GHz之间的倒置频谱，其频谱指数$α$（$S_ν\ Propto n $）为$ 1.19 \ pm 0.43 $，而接近的小叶组成部分则为$ -0.54.54.54.54.54.54。基于计数器和接近裂片之间测得的通量不对称，我们约束FFA前景的平均数量密度$ n _ {\ rm e} $作为$ 1.8 \ times 10^{4} {4}〜{\ rm cm^{-3}}}}} \ sim n _}。 10^{6}〜{\ rm cm^{ - 3}} $。这些结果表明，FFA前景的观察性能可以通过在中央$ \ sim \ sim 1 $ 3C 84区域的块状云中的密集离子气体和/或组装块状云的组装来解释。
The nearby bright radio galaxy 3C 84 at the center of Perseus cluster is one of the ideal targets to explore the jet in active galactic nuclei (AGNs) and its parsec-scale environment. A recent research of Fujita & Nagai revealed the existence of the northern counter-jet component (N1) located at $\sim$ 2 mas north from the central core in VLBI images at 15 and 43 GHz and they are explained by the free-free absorption (FFA) due to an ionized plasma foreground. Here we report a new quasi-simultaneous observation of 3C 84 with the Korean VLBI Network (KVN) at 86 GHz and the KVN and VERA (VLBI Exploration of Radio Astrometry) Array (KaVA) at 43 GHz in 2016 February. We succeeded the first detection of N1 at 86 GHz and the data show that N1 still has an inverted spectrum between 43 and 86 GHz with its spectral index $α$ ($S_ν \propto ν^α$) of $1.19 \pm 0.43$, while the approaching lobe component has the steep spectrum with the index of $-0.54 \pm 0.30$. Based on the measured flux asymmetry between the counter and approaching lobes, we constrain the averaged number density of the FFA foreground $n_{\rm e}$ as $1.8 \times 10^{4}~{\rm cm^{-3}} \lesssim n_{\rm e} \lesssim 1.0 \times 10^{6}~{\rm cm^{-3}}$. Those results suggest that the observational properties of the FFA foreground can be explained by the dense ionized gas in the circumnuclear disk and/or assembly of clumpy clouds at the central $\sim 1$ pc region of 3C 84.
