Estimation of the magnetic field strength from ALMA dust polarization in the protocluster G327.29
6 affiliations
- 1Departamento de Astronomía, Universidad de Concepción
- 2Department of Astronomy, School of Science, The University of Tokyo
- 3School of Astronomy and Space Science, Nanjing University
- 4Academia Sinica Institute of Astronomy and Astrophysics
- 5National Astronomical Observatory of Japan, National Institutes of Natural Sciences
- 6Department of Astronomy, University of Florida
Abstract
Magnetic fields and turbulence may play crucial roles in the evolution of molecular clouds and ultimately in the formation of dense cores and stars. Despite being studied in many molecular clouds, the exact role of magnetic fields and turbulence in star formation is still poorly understood. We report the high-resolution plane of sky magnetic field (Bpos) morphology towards the high-mass star-forming region G327.29, obtained with the 12-metre configuration of the Atacama Large Millimeter/sub-millimeter Array (ALMA) telescope. From our analysis, we obtain a complex Bpos morphology in which the magnetic field orientation is uniformly distributed across the entire range from −90 to +90 deg. The observed area is composed of one filament and one dense central clump, both of which harbour multiple dense cores. The total magnetic field strengths (Btot) in these regions are 1.7 ± 0.8 and 3.6 ± 1.5 mG at a number density (n) of 1.5 ± 0.3 × 106 and 2.3 ± 0.7 × 106 cm−3, derived using the Davis–Chandrasekhar–Fermi (DCF) angular dispersion function (ADF) method. The corresponding Btot obtained using the Skalidis–Tassis (ST) method are 0.6 ± 0.3 and 1.1 ± 0.5 mG, approximately three times lower. The virial parameters (αvir) in these regions are 2.8 ± 1.9 and 0.5 ± 0.4, suggesting that the regions may be gravitationally bound or unbound after accounting the errors. The ratio of turbulent to magnetic energy (∼0.17–0.34) indicates that the magnetic field is dynamically more important than turbulence. The relative influence of turbulence and magnetic fields on core dynamics appears to depend on how Btot scales with gas density (ρ) in the densest regions. In summary, this work, enabled by high-resolution ALMA observations, presents a comprehensive analysis of the relative roles of magnetic fields, turbulence, and gravity in regulating high-mass star formation in G327.29.
Related
- The SIMPLIFI survey: Polarization of dense filaments with SOFIA. III. Relative orientations of antenna temperature gradients with the magnetic field in the DR21 molecular cloud
- Disentangling 3D Magnetic Field Geometry from Turbulence: A Polarization-Based Classification Method
- Estimates of Magnetic Field Strength in the Solar Corona Using Observations of Thermal Radio Emission at Low Frequencies
- Estimates of magnetic field strength in the solar corona using observations of thermal radio emission at low frequencies
- Forward Modeling of Spectral-Line Polarization for Weak Magnetic-Field Imaging
BibTeX
@article{koley2026estimation,
title = {{Estimation of the magnetic field strength from ALMA dust polarization in the protocluster G327.29}},
author = {Koley A. and Sanhueza P. and Stutz A. M. and Liu J. and Saha P. and Olguin F. A. and Ginsburg A. and Sandoval-Garrido N. and Castro-Toledo N.},
journal = {Astronomy \& Astrophysics},
year = {2026},
month = nov,
doi = {10.1051/0004-6361/202660048},
url = {https://doi.org/10.1051/0004-6361/202660048},
note = {CC BY},
}
RIS
TY - JOUR
TI - Estimation of the magnetic field strength from ALMA dust polarization in the protocluster G327.29
AU - Koley A.
AU - Sanhueza P.
AU - Stutz A. M.
AU - Liu J.
AU - Saha P.
AU - Olguin F. A.
AU - Ginsburg A.
AU - Sandoval-Garrido N.
AU - Castro-Toledo N.
PY - 2026
DA - 2026/11/04
JO - Astronomy & Astrophysics
DO - 10.1051/0004-6361/202660048
UR - https://doi.org/10.1051/0004-6361/202660048
AB - Magnetic fields and turbulence may play crucial roles in the evolution of molecular clouds and ultimately in the formation of dense cores and stars. Despite being studied in many molecular clouds, the exact role of magnetic fields and turbulence in star formation is still poorly understood. We report the high-resolution plane of sky magnetic field (Bpos) morphology towards the high-mass star-forming region G327.29, obtained with the 12-metre configuration of the Atacama Large Millimeter/sub-millimeter Array (ALMA) telescope. From our analysis, we obtain a complex Bpos morphology in which the magnetic field orientation is uniformly distributed across the entire range from −90 to +90 deg. The observed area is composed of one filament and one dense central clump, both of which harbour multiple dense cores. The total magnetic field strengths (Btot) in these regions are 1.7 ± 0.8 and 3.6 ± 1.5 mG at a number density (n) of 1.5 ± 0.3 × 106 and 2.3 ± 0.7 × 106 cm−3, derived using the Davis–Chandrasekhar–Fermi (DCF) angular dispersion function (ADF) method. The corresponding Btot obtained using the Skalidis–Tassis (ST) method are 0.6 ± 0.3 and 1.1 ± 0.5 mG, approximately three times lower. The virial parameters (αvir) in these regions are 2.8 ± 1.9 and 0.5 ± 0.4, suggesting that the regions may be gravitationally bound or unbound after accounting the errors. The ratio of turbulent to magnetic energy (∼0.17–0.34) indicates that the magnetic field is dynamically more important than turbulence. The relative influence of turbulence and magnetic fields on core dynamics appears to depend on how Btot scales with gas density (ρ) in the densest regions. In summary, this work, enabled by high-resolution ALMA observations, presents a comprehensive analysis of the relative roles of magnetic fields, turbulence, and gravity in regulating high-mass star formation in G327.29.
SN - 0004-6361
SN - 1432-0746
ER -