Power-law tails in turbulent magnetic field PDFs arise from intermittent Poisson-distributed shocks convolved with a lognormal core, with tail asymmetry determined by the ratio of fast to slow MHD shocks.
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Magnetic fields in star formation: from clouds to cores
20 Pith papers cite this work, alongside 47 external citations. Polarity classification is still indexing.
20
Pith papers citing it
47
external citations · Pith
abstract
In this chapter we review recent advances in understanding the roles that magnetic fields play throughout the star formation process, gained through observations and simulations of molecular clouds, the dense, star-forming phase of the magnetised, turbulent interstellar medium (ISM). Recent results broadly support a picture in which the magnetic fields of molecular clouds transition from being gravitationally sub-critical and near equipartition with turbulence in low-density cloud envelopes, to being energetically sub-dominant in dense, gravitationally unstable star-forming cores. Magnetic fields appear to play an important role in the formation of cloud substructure by setting preferred directions for large-scale gas flows in molecular clouds, and can direct the accretion of material onto star-forming filaments and hubs. Low-mass star formation may proceed in environments close to magnetic criticality; high-mass star formation remains less well-understood, but may proceed in more supercritical environments. The interaction between magnetic fields and (proto)stellar feedback may be particularly important in setting star formation efficiency. We also review a range of widely-used techniques for quantifying the dynamic importance of magnetic fields, concluding that better-calibrated diagnostics are required in order to use the spectacular range of forthcoming observations and simulations to quantify our emerging understanding of how magnetic fields influence the outcome of the star formation process.
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Multi-scale observations of dense core G205.46-14.56-N2 show a quadruple protostellar system whose symmetry, outflows, and kinematics match simulations of rotational fragmentation, providing the first claimed evidence for this pathway in high-order multiples.
Sub-Alfvénic MHD simulations with projection effects reproduce the range of observed polarization (μ, σ) values in Orion ISF, showing these statistics alone cannot constrain the 3D Alfvén Mach number.
Magnetic fields remain aligned with projected gravity throughout the DR21 ridge and sub-filaments, indicating guided accretion at rates that can build the ridge in about one million years.
The paper outlines the goals for the SKA-Mid Galactic Plane survey at 10-15 GHz to deliver the first uniform high-resolution view of ionized structures and feedback in the Milky Way.
Polarization observations reveal scale-dependent differences in magnetic field morphology between molecular clouds and clumps, a velocity-dispersion correlation, and unreliable field-strength estimates that contradict flux conservation.
Low-column-density filaments align parallel to magnetic fields while high-column-density wide filaments align perpendicular, with transition at roughly 0.8-8 x 10^21 cm^-2; projection effects analyzed statistically.
Observational study of MBM12 shows CO-to-H2 conversion factor near galactic average with density-dependent variations, high virial parameters decreasing at small scales, broken power-law mass-size relations indicating external pressure, and magnetic field orientation transition at N(H2) = 4.5e21 cm-
Oblique filament collisions lead to gravitational collapse of the compressed cloud when post-collision |gravitational energy| exceeds kinetic plus thermal plus magnetic energies, with lower angles and lower velocities favoring hub-filament formation.
High-resolution magnetic field maps of M17 SW reveal gravity-dominated energy budget with magnetic fields regulating collapse and accretion channels in a near-equipartition state.
Core-scale magnetic fields in star-forming regions are more disordered than cloud-scale fields and align randomly with core orientations and velocity gradients.
Reanalysis of 79 solar twins indicates the Sun's chemical peculiarity is largely explained by Galactic chemical evolution, with 2-6 candidates possibly showing planetary engulfment.
SKAO will enable detection of synchrotron emission from prestellar cores to probe their magnetic field properties in nearby star-forming regions.
Correlations between HI velocity complexity and depolarization plus links between Faraday depth moments and neutral gas structure indicate neutral-dominated ISM regions contribute substantially to diffuse synchrotron emission and Faraday rotation.
Stronger radiation environments produce more massive, hotter protostellar discs whose fragments are large and disruptive rather than planetary-mass.
High-resolution dust polarization and C18O observations in Cepheus A show gravity driving gas accretion while magnetic tension regulates turbulence, producing ordered flows at 2.1e-4 solar masses per year with coherent B-field alignment across scales.
Reviews SKA techniques for reconstructing 3D magnetic field vectors in the ISM but presents no new data or derivations.
The paper describes the expected capabilities of the SKA-Mid survey to produce a complete map of the Milky Way's magnetic field in the southern hemisphere using rotation measures and polarized emission.
The paper presents predictions and observational plans for Zeeman effect measurements with SKA to provide statistical data on magnetic field strengths across scales in molecular clouds.
Review chapter summarizing the importance of small-scale galactic magnetic fields and proposing SKA observation strategies.
citing papers explorer
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The dynamical origin of the magnetic field distributions in compressible turbulence
Power-law tails in turbulent magnetic field PDFs arise from intermittent Poisson-distributed shocks convolved with a lognormal core, with tail asymmetry determined by the ratio of fast to slow MHD shocks.
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Formation of a Protostellar Multiple System via Rotational Fragmentation
Multi-scale observations of dense core G205.46-14.56-N2 show a quadruple protostellar system whose symmetry, outflows, and kinematics match simulations of rotational fragmentation, providing the first claimed evidence for this pathway in high-order multiples.
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Projection Is All You Need: Interpreting Polarization Measurements in the Orion Clouds with Sub-Alfv\'enic MHD Simulations
Sub-Alfvénic MHD simulations with projection effects reproduce the range of observed polarization (μ, σ) values in Orion ISF, showing these statistics alone cannot constrain the 3D Alfvén Mach number.
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SIMPLIFI -- Study of Interstellar Magnetic Polarization: a Legacy Investigation of Filaments. I. Magnetically-Guided Accretion onto the DR21 Ridge
Magnetic fields remain aligned with projected gravity throughout the DR21 ridge and sub-filaments, indicating guided accretion at rates that can build the ridge in about one million years.
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The 10-15 GHz radio continuum survey of the Galactic Plane with SKAO
The paper outlines the goals for the SKA-Mid Galactic Plane survey at 10-15 GHz to deliver the first uniform high-resolution view of ionized structures and feedback in the Milky Way.
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Characterising magnetic fields at the onset of star cluster formation: From giant molecular clouds to infrared dark clumps
Polarization observations reveal scale-dependent differences in magnetic field morphology between molecular clouds and clumps, a velocity-dispersion correlation, and unreliable field-strength estimates that contradict flux conservation.
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Statistical analysis of the relative orientations between filaments and magnetic fields using Herschel and Planck data in star-forming regions
Low-column-density filaments align parallel to magnetic fields while high-column-density wide filaments align perpendicular, with transition at roughly 0.8-8 x 10^21 cm^-2; projection effects analyzed statistically.
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B-Fields and Star Formation across Scales with TRAO (B-FROST): CO Abundances, Dynamics and Relative Orientations in the Translucent High Latitude Cloud MBM12
Observational study of MBM12 shows CO-to-H2 conversion factor near galactic average with density-dependent variations, high virial parameters decreasing at small scales, broken power-law mass-size relations indicating external pressure, and magnetic field orientation transition at N(H2) = 4.5e21 cm-
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Evolution of compressed clouds formed by filament coalescence. I. Oblique collisions
Oblique filament collisions lead to gravitational collapse of the compressed cloud when post-collision |gravitational energy| exceeds kinetic plus thermal plus magnetic energies, with lower angles and lower velocities favoring hub-filament formation.
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BISTRO Survey: Gravity-Dominated and Magnetically Regulated Star Formation in M17 SW
High-resolution magnetic field maps of M17 SW reveal gravity-dominated energy budget with magnetic fields regulating collapse and accretion channels in a near-equipartition state.
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Magnetic field alignment with dense cores in the transition between cloud and core scales
Core-scale magnetic fields in star-forming regions are more disordered than cloud-scale fields and align randomly with core orientations and velocity gradients.
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The Sun's chemical peculiarity: disentangling Galactic chemical evolution and planetary engulfment in solar twins
Reanalysis of 79 solar twins indicates the Sun's chemical peculiarity is largely explained by Galactic chemical evolution, with 2-6 candidates possibly showing planetary engulfment.
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Early phases of star formation with SKAO: synchrotron emission from dense starless cores in molecular clouds
SKAO will enable detection of synchrotron emission from prestellar cores to probe their magnetic field properties in nearby star-forming regions.
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Imprints of the Neutral Interstellar Medium on Polarized Synchrotron Emission and Faraday Rotation
Correlations between HI velocity complexity and depolarization plus links between Faraday depth moments and neutral gas structure indicate neutral-dominated ISM regions contribute substantially to diffuse synchrotron emission and Faraday rotation.
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The Impact of Radiation Environment on the Evolution and Fragmentation of Protostellar Discs
Stronger radiation environments produce more massive, hotter protostellar discs whose fragments are large and disruptive rather than planetary-mass.
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Evidence for the gravity-driven and magnetically-regularized gas flows feeding the massive protostellar cluster in Cepheus A
High-resolution dust polarization and C18O observations in Cepheus A show gravity driving gas accretion while magnetic tension regulates turbulence, producing ordered flows at 2.1e-4 solar masses per year with coherent B-field alignment across scales.
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3D Magnetic Field Vectors in Space: Bubbles, Clouds, and Filaments
Reviews SKA techniques for reconstructing 3D magnetic field vectors in the ISM but presents no new data or derivations.
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The magnetic field in the Milky Way Galaxy: from large to small scales
The paper describes the expected capabilities of the SKA-Mid survey to produce a complete map of the Milky Way's magnetic field in the southern hemisphere using rotation measures and polarized emission.
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Measuring Magnetic Field Strengths in Galactic Star-forming Regions via the Zeeman Effect with the SKA
The paper presents predictions and observational plans for Zeeman effect measurements with SKA to provide statistical data on magnetic field strengths across scales in molecular clouds.
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Small-scale Magnetic Fields in the Milky Way and Nearby Galaxies
Review chapter summarizing the importance of small-scale galactic magnetic fields and proposing SKA observation strategies.