Massive Protostars in a Protocluster—A Multi-scale ALMA View of G35.20-0.74N
Journal article, 2022

We present a detailed study of the massive star-forming region G35.2-0.74N with Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm multi-configuration observations. At 0.″2 (440 au) resolution, the continuum emission reveals several dense cores along a filamentary structure, consistent with previous ALMA 0.85 mm observations. At 0.″03 (66 au) resolution, we detect 22 compact sources, most of which are associated with the filament. Four of the sources are associated with compact centimeter continuum emission, and two of these are associated with H30α recombination line emission. The H30α line kinematics shows the ordered motion of the ionized gas, consistent with disk rotation and/or outflow expansion. We construct models of photoionized regions to simultaneously fit the multiwavelength free-free fluxes and the H30α total fluxes. The derived properties suggest the presence of at least three massive young stars with nascent hypercompact H ii regions. Two of these ionized regions are surrounded by a large rotating structure that feeds two individual disks, revealed by dense gas tracers, such as SO2, H2CO, and CH3OH. In particular, the SO2 emission highlights two spiral structures in one of the disks and probes the faster-rotating inner disks. The 12CO emission from the general region reveals a complex outflow structure, with at least four outflows identified. The remaining 18 compact sources are expected to be associated with lower-mass protostars forming in the vicinity of the massive stars. We find potential evidence for disk disruption due to dynamic interactions in the inner region of this protocluster. The spatial distribution of the sources suggests a smooth overall radial density gradient without subclustering, but with tentative evidence of primordial mass segregation.

Author

Yichen Zhang

University of Virginia

RIKEN

Kei E.I. Tanaka

National Astronomical Observatory of Japan

University of Colorado at Boulder

Jonathan Tan

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

University of Virginia

Yao-Lun Yang

RIKEN

University of Virginia

Eva Greco

University of Virginia

M. T. Beltrán

Arcetri Astrophysical Observatory

N. Sakai

RIKEN

James M. De Buizer

NASA Ames Research Center

Viviana Rosero

National Radio Astronomy Observatory Socorro

Rubén Fedriani

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

G. Garay

University of Chile (UCH)

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 936 1 68

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Fusion, Plasma and Space Physics

DOI

10.3847/1538-4357/ac847f

More information

Latest update

12/26/2022