An Ionized Outflow in Orion-KL Source I?

Melvyn Wright; Tomoya Hirota; Jan Forbrich; Richard Plambeck; John Bally; Ciriaco Goddi; Adam Ginsburg; Brett McGuire

doi:10.3847/1538-4357/acac2c

The Astrophysical Journal (Jan 2023)

An Ionized Outflow in Orion-KL Source I?

Melvyn Wright,
Tomoya Hirota,
Jan Forbrich,
Richard Plambeck,
John Bally,
Ciriaco Goddi,
Adam Ginsburg,
Brett McGuire

Affiliations

Melvyn Wright: ORCiD; Department of Astronomy, University of California, Berkeley , 501 Campbell Hall, Berkeley, CA 94720-3441, USA ; [email protected]
Tomoya Hirota: ORCiD; Mizusawa VLBI Observatory, National Astronomical Observatory of Japan , 2-12, Hoshigaoka, Mizusawa, Oshu, Iwate 023-0861, Japan
Jan Forbrich: ORCiD; Centre for Astrophysics Research, University of Hertfordshire , College Lane, Hatfield, AL10 9AB, UK
Richard Plambeck: ORCiD; Radio Astronomy Lab, University of California, Berkeley , 501 Campbell Hall, Berkeley, CA 94720-3441, USA
John Bally: ORCiD; CASA, University of Colorado , 389-UCB, Boulder, CO 80309, USA
Ciriaco Goddi: ORCiD; Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Departamento de Astronomia, Universidade de São Paulo , São Paulo, SP 05508-090, Brazil; Dipartimento di Fisica, Università degli Studi di Cagliari , SP Monserrato-Sestu km 0.7, I-09042 Monserrato, Italy; INAF—Osservatorio Astronomico di Cagliari , via della Scienza 5, I-09047 Selargius (CA), Italy; INFN, Sezione di Cagliari, Cittadella Univ. , I-09042 Monserrato (CA), Italy
Adam Ginsburg: ORCiD; Department of Astronomy, University of Florida , 211 Bryant Space Science Center, P.O Box 112055, Gainesville, FL 32611-2055 USA
Brett McGuire: ORCiD; Department of Chemistry, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; National Radio Astronomy Observatory , Charlottesville, VA 22903, USA

DOI: https://doi.org/10.3847/1538-4357/acac2c
Journal volume & issue: Vol. 945, no. 1
p. 14

Abstract

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We present images at 6 and 14 GHz of Source I (SrcI) in the Kleinmann–Low Nebula in Orion. At higher frequencies, from 43 to 340 GHz, images of this source are dominated by thermal emission from dust in a 100 au diameter circumstellar disk, but at 6 and 14 GHz the emission is elongated along the minor axis of the disk, aligned with the SiO bipolar outflow from the central object. Gaussian fits to the 6, 14, 43, and 99 GHz images find a component along the disk minor axis whose flux and length vary with frequency consistent with free–free emission from an ionized outflow. The data favor a broad outflow from a disk wind, rather than a narrow ionized jet. SrcI was undetected in higher-resolution 5 GHz e-MERLIN observations obtained in 2021. The 5–6 GHz structure of SrcI may be resolved out by the high sidelobe structure of the e-MERLIN synthesized beam, or be time variable.

Radio continuum emission

Published in The Astrophysical Journal

ISSN: 1538-4357 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy: Astrophysics
Website: https://iopscience.iop.org/journal/0004-637X

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