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arXiv 2502.03097astro-ph.HEastro-ph.GA
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TeV候选源的高分辨率射电观测

High-resolution radio observations of TeV candidate sources

J. Kőmíves, K. É. Gabányi, S. Frey, Z. Paragi, T. An, E. Kun

AI总结:

本文利用EVN和e-MERLIN对两个光学无活动迹象的TeV候选源进行高分辨率双频射电观测,通过定位致密射电辐射并测定谱指数、亮温度等参数,揭示它们均寄宿着具有陡峭谱的暗弱致密射电AGN。

摘要:

射电噪活动星系核(AGN)的喷流指向接近我们的视线方向,构成了河外γ射线源的主体,并对在更高能段观测到的辐射有显著贡献。即将建成的切伦科夫望远镜阵列(CTA)预计将探测到更暗的TeV天体,从而导致非耀变体河外高能源所占比例预期增加。在此,我们展示利用欧洲甚长基线干涉网(EVN)和增强型多单元远程连接干涉仪网络(e-MERLIN)对TeV候选源列表中两个暗弱射电源进行的双频(1.7和5 GHz)观测结果。它们在光学光谱中没有显示出核活动的迹象,但据推测它们可能包含被宿主星系的光芒掩盖的暗弱AGN。我们利用毫角秒级分辨率的射电数据,试图定位致密射电辐射特征的位置,确定其谱指数、射电功率、亮温度以及射电-X射线光度比,从而确定射电辐射的起源。我们的结果表明,这两个在光学上看似无活动的星系都寄宿着具有陡峭谱的暗弱致密射电辐射AGN。

英文摘要:

Radio-loud active galactic nuclei (AGN) with their jets pointed close to our line of sight constitute the majority of extragalactic $γ$-ray sources and significantly contribute to the radiation observed in the even higher energy regime. The upcoming Cherenkov Telescope Array (CTA) is expected to detect fainter TeV objects, leading to an anticipated increase in the proportion of non-blazar extragalactic high-energy sources. Here we present the results of our dual-frequency (1.7 and 5~GHz) European VLBI Network (EVN) and enhanced Multi Element Remotely Linked Interferometer Network (e-MERLIN) observations of two faint radio sources from the list of TeV candidate sources. They do not show signs of nuclear activity in their optical spectra, but they were hypothesized to contain faint AGN that is outshone by the host galaxy. We used the mas-scale resolution radio data to try to pinpoint the location of the compact radio emitting feature, determine its spectral index, radio power, brightness temperature and radio-X-ray luminosity ratio and thus identify the origin of the radio emission. Our results suggest that both optically passive-looking galaxies host faint compact radio-emitting AGN with steep spectra.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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