The Explosion in Orion-KL as Seen by Mosaicking the Magnetic Field with ALMA

Abstract

We present the first linear-polarization mosaicked observations performed by the Atacama Large Millimeter/submillimeter Array (ALMA). We mapped the Orion-KLeinmann-Low (Orion-KL) nebula using super-sampled mosaics at 3.1 and 1.3 mm as part of the ALMA Extension and Optimization of Capabilities (EOC) program. We derive the magnetic field morphology in the plane of the sky by assuming that dust grains are aligned with respect to the ambient magnetic field. At the center of the nebula, we find a quasi-radial magnetic field pattern that is aligned with the explosive CO outflow up to a radius of approximately 12 arc-seconds (~ 5000 au), beyond which the pattern smoothly transitions into a quasi-hourglass shape resembling the morphology seen in larger-scale observations by the James-Clerk-Maxwell Telescope (JCMT). We estimate an average magnetic field strength $⟨B⟩=9.4$ mG and a total magnetic energy of 2 x 10^45 ergs, which is three orders of magnitude less than the energy in the explosive CO outflow. We conclude that the field has been overwhelmed by the outflow and that a shock is propagating from the center of the nebula, where the shock front is seen in the magnetic field lines at a distance of ~ 5000 au from the explosion center.

Accepted for publication in ApJ

References in corpus (16)

• The distance to the Orion Nebula
• Radiative torques: Analytical Model and Basic Properties
• The JCMT BISTRO Survey: The magnetic field strength in the Orion A filament
• Monitoring the Large Proper Motions of Radio Sources in the Orion BN/KL Region
• ALMA observations of dust polarization and molecular line emission from the Class 0 protostellar source Serpens SMM1
• The ALMA View of the OMC1 Explosion in Orion
• The complexity of Orion: an ALMA view. II. gGg'-Ethylene Glycol and Acetic Acid
• The Orion Protostellar Explosion and Runaway Stars Revisited: Stellar Masses, Disk Retention, and an Outflow from BN
• New Evidence for the Dynamical Decay of a Multiple System in the Orion Kleinmann-Low Nebula
• ALMA Imaging of Millimeter/Submillimeter Continuum Emission in Orion KL
• OMC-1 dust polarisation in ALMA Band 7: Diagnosing grain alignment mechanisms in the vicinity of Orion Source I
• NICMOS Observations of Shocked H_2 in Orion
• Characterizing the accuracy of ALMA linear-polarization mosaics
• The complexity of Orion: an ALMA view III. The explosion impact
• Evidence for dense gas heated by the explosion in Orion KL
• Outflows, cores and magnetic field orientations in W43-MM1 as seen by ALMA

Cited by in corpus (13)

• Gravity Driven Magnetic Field at ~1000 au Scales in High-mass Star Formation
• Magnetic fields in star formation: a complete compilation of all the DCF estimations
• Magnetic Fields in Massive Star-Forming Regions (MagMaR) I. Linear Polarized Imaging of the UCHII Region G5.89-0.39
• OMC-1 dust polarisation in ALMA Band 7: Diagnosing grain alignment mechanisms in the vicinity of Orion Source I
• The Mechanical Alignment of Dust (MAD) I: On the spin-up process of fractal grains by a gas-dust drift
• Polarization from Aligned Dust Grains in the $\beta$ Pic Debris Disk
• Is the mm/submm dust polarization a robust tracer of the magnetic field topology in protostellar envelopes? A model exploration
• Magnetic fields and outflows in the large Bok globule CB 54
• Mapping physical parameters in Orion KL at high spatial resolution
• The origin of dust polarization in the Orion Bar
• A Tale of Three: Magnetic Fields along the Orion Integral-Shaped Filament as Revealed by JCMT BISTRO survey
• Probing the role of magnetic fields in star-forming filaments: NIKA2-Pol commissioning results toward OMC-1
• Evidence for the gravity-driven and magnetically-regularized gas flows feeding the massive protostellar cluster in Cepheus A