文章基本信息

标题：VLBA Observations of Strong Anisotripic Radio Scattering Toward the Orion Nebula
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作者：Marina Kounkel ; Lee Hartmann ; Laurent Loinard 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2018
卷号：155
期号：5
页码：1-5
DOI：10.3847/1538-3881/aabc58
语种：English
出版社：American Institute of Physics
摘要：We present observations of VLBA 20, a radio source found toward the edge of the Orion Nebula Cluster (ONC). Nonthermal emission dominates the spectral energy distribution of this object from the radio to mid-infrared regime, suggesting that VLBA 20 is extragalactic. This source is heavily scattered in the radio regime. Very Long Baseline Array observations resolve it to ∼34×19 mas at 5 GHz, and the wavelength dependence of the scattering disk is consistent with ν−2 at other frequencies. The origin of the scattering is most likely the ionized X-ray emitting gas from the winds of the most massive stars of the ONC. The scattering is highly anisotropic, with the axis ratio of 2:1, higher than what is typically observed toward other sources.
关键词：HII regions;ISM: magnetic fields;scattering