Resolving the Structure and Kinematics of the BN Object at $0\text{.}"2$ Resolution

Abstract

We present sensitive 7 mm observations of the H53$\alpha$ recombination line and adjacent continuum, made toward the Orion BN/KL region. In the continuum we detect the BN object, the radio source I (GMR I) and the radio counterpart of the infrared source n (Orion-n). Comparing with observations made at similar angular resolutions but lower frequency, we discuss the spectral indices and angular sizes of these sources. In the H53$\alpha$ line we only detect the BN object. This is the first time that radio recombination lines are detected from this source. The LSR radial velocity of BN from the H53$\alpha$ line, $v_{LSR}=20.1\pm 2.1$ km s${}^{-1}$, is consistent with that found from previous studies in near-infared lines. While the continuum emission is expected to have considerable optical depth at 7 mm, the observed H53$\alpha$ line emission is consistent with an optically-thin nature and we discuss possible explanations for this apparent discrepancy. There is evidence of a velocity gradient, with the NE part of BN being redshifted by $\sim 10$ km s${}^{-1}$ with respect to the SW part. This is consistent with the suggestion of Jiang et al. that BN may be driving an ionized outflow along that direction.

16 pages, 3 figures

References in corpus (5)

• The distance to the Orion Nebula
• The Electron Temperature Gradient in the Galactic Disk
• Monitoring the Large Proper Motions of Radio Sources in the Orion BN/KL Region
• Imaging the Ionized Disk of the High-Mass Protostar Orion-I
• High Resolution $\lambda$=1mm CARMA Observations of Large Molecules in Orion-KL

Cited by in corpus (17)

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• ALMA Imaging of Millimeter/Submillimeter Continuum Emission in Orion KL
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• Molecular outflows: Explosive versus protostellar
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• The Ionized Circumstellar Envelopes of Orion Source I and the Becklin Neugebauer Object
• ALMA and VLA observations of recombination lines and continuum toward the Becklin-Neugebauer object in Orion
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