Magnetic Fields in Massive Star-forming Regions (MagMaR). I. Linear Polarized Imaging of the Ultracompact H ii Region G5.89–0.39

• Published in: The Astrophysical journal Vol. 913; no. 1; pp. 29 - 49
• Main Authors: Fernández-López, M., Sanhueza, P., Zapata, L. A., Stephens, I., Hull, C., Zhang, Q., Girart, J. M., Koch, P. M., Cortés, P., Silva, A., Tatematsu, K., Nakamura, F., Guzmán, A. E., Nguyen Luong, Q., Guzmán Ccolque, E., Tang, Y.-W., Chen, H.-R. V.
• Format: Journal Article
• Language: English
• Published: Philadelphia The American Astronomical Society 01.05.2021; IOP Publishing
• Subjects: Arches; Astrophysics; Belts; Continuum radiation; Dispersal; Dispersion; Dust; Dust continuum emission; Dust emission; Filaments; Interstellar magnetic fields; Magnetic fields; Massive stars; Polarimetry; Protostars; Radio telescopes; Star & galaxy formation; Star formation; Stars & galaxies
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/abf2b6

Abstract We report 1.2 mm polarized continuum emission observations carried out with the Atacama Large Millimeter/submillimeter Array toward the high-mass star formation region G5.89–0.39. The observations show a prominent 0.2 pc north–south filamentary structure. The ultracompact H ii region in G5.89–0.39 breaks the filament into two pieces. Its millimeter emission shows a dusty belt with a mass of 55–115 M ⊙ and 4500 au in radius, surrounding an inner part comprising mostly ionized gas, with dust emission only accounting for about 30% of the total millimeter emission. We also found a lattice of convex arches that may be produced by dragged dust and gas from the explosive dispersal event involving the O5 Feldt’s star. The north–south filament has a mass between 300 and 600 M ⊙ and harbors a cluster of about 20 mm envelopes with a median size and mass of 1700 au and 1.5 M ⊙ , respectively, some of which are already forming protostars. We interpret the polarized emission in the filament as mainly coming from magnetically aligned dust grains. The polarization fraction is ∼4.4% in the filaments and 2.1% at the shell. The magnetic fields are along the North Filament and perpendicular to the South Filament. In the Central Shell, the magnetic fields are roughly radial in a ring surrounding the dusty belt between 4500 and 7500 au, similar to the pattern recently found in the surroundings of Orion BN/KL. This may be an independent observational signpost of explosive dispersal outflows and should be further investigated in other regions.