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arXiv · 1804.01555

VLBA Observations of Strong Anisotripic Radio Scattering towards the Orion Nebula

Marina Kounkel·Lee Hartmann·Laurent Loinard·Amy J. Mioduszewski·Luis F. Rodríguez·Gisela N. Ortiz-León·Michael D. Johnson·Rosa M. Torres·Cesar Briceño
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Abstract

We present observations of VLBA 20, a radio source found towards the edge of the Orion Nebula Cluster (ONC). Nonthermal emission dominates the spectral energy distribution of this object from 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 ~34x19 mas at 5 GHz, and the wavelength dependence of the scattering disk is consistent with $\nu^{-2}$ 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 towards other sources.

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Marina Kounkel, Lee Hartmann, Laurent Loinard, Amy J. Mioduszewski, Luis F. Rodríguez, Gisela N. Ortiz-León, Michael D. Johnson, Rosa M. Torres, Cesar Briceño. 2018-04-04. VLBA Observations of Strong Anisotripic Radio Scattering towards the Orion Nebula. https://doi.org/10.3847/1538-3881%2Faabc58

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