Colloquium Abstract - Kauffmann - 2026Jan09

September 11, 2026

11:00am Mountain

Jens Kauffmann (MIT)

 

A detailed Look at Magnetized Accretion in Star Formation

 

Abstract

Understanding what regulates star formation in molecular clouds remains a central question in galactic and extragalactic astrophysics. Magnetic fields, alongside turbulence, have long been recognized as potentially playing a crucial role in influencing the gravitational collapse of star-forming gas. Unfortunately, observational characterizations of the multi-scale magnetic field structure of molecular clouds continue to be challenging. Such observations need to cover large regions at high resolution, if one wishes to study how dense star-forming filaments of ~0.1 pc width emerge in large molecular cloud complexes of ~10 pc size.

In this talk I present result from an ongoing SOFIA-based study in which we probe magnetic field orientations over the critical spatial range of about 10–0.1 pc. In a first paper we targeted the DR21 star-forming region within the Cygnus-X complex (Pillai et al. 2026ApJ..1004..247P). This is one target within the larger SIMPLIFI survey of magnetized molecular clouds with SOFIA. Comparison of magnetic field directions and intensity gradients supports the well-established picture that clouds form from strongly magnetized, sub-Alfvénic, magnetically subcritical gas.

A new and key insight of this work is the fact that the magnetic field orientation is aligned with gravitational acceleration on all spatial scales. This configuration is consistent with a scenario in which magnetic fields do not impede but guide accretion into molecular clouds. Low line-of-sight gas velocities observed in molecular emission lines are seemingly in tension with large freefall speeds expected in magnetically-guided accretion — but this is naturally explained through projection effects. We use observations from the multi-target LEGO imaging line survey on the IRAM 30m telescope (Kauffmann & Barnes. 2022EPJWC.26500019K) to study this in detail (Imming et al. In prep.). These studies are a small subset of completed (Kumar et al. 2026arXiv260300246K) and ongoing (Kauffmann et al. In prep.) studies of targets within the SIMPLIFI survey, on which I will touch briefly.

The SIMPLIFI and LEGO data do in combination demonstrate the high value of single-dish observations covering large fields of view. I briefly outline how upcoming surveys and instruments might further contribute to the study of magnetic fields and cloud properties in the Milky Way.


Local Host: Brian Svoboda

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