The Magnetic Field in the Milky Way Filamentary Bone G47

Ian W. Stephens*, Philip C. Myers, Catherine Zucker, James M. Jackson, B. G. Andersson, Rowan Smith, Archana Soam, Cara Battersby, Patricio Sanhueza, Taylor Hogge, Howard A. Smith, Giles Novak, Sarah Sadavoy, Thushara G.S. Pillai, Zhi Yun Li, Leslie W. Looney, Koji Sugitani, Simon Coudé, Andrés Guzmán, Alyssa GoodmanTakayoshi Kusune, Fábio P. Santos, Leah Zuckerman, Frankie Encalada

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Star formation primarily occurs in filaments where magnetic fields are expected to be dynamically important. The largest and densest filaments trace the spiral structure within galaxies. Over a dozen of these dense (∼104 cm-3) and long (>10 pc) filaments have been found within the Milky Way, and they are often referred to as "bones."Until now, none of these bones has had its magnetic field resolved and mapped in its entirety. We introduce the SOFIA legacy project FIELDMAPS which has begun mapping ∼10 of these Milky Way bones using the HAWC+ instrument at 214 μm and 18.″2 resolution. Here we present a first result from this survey on the ∼60 pc long bone G47. Contrary to some studies of dense filaments in the Galactic plane, we find that the magnetic field is often not perpendicular to the spine (i.e., the center line of the bone). Fields tend to be perpendicular in the densest areas of active star formation and more parallel or random in other areas. The average field is neither parallel nor perpendicular to the Galactic plane or the bone. The magnetic field strengths along the spine typically vary from ∼20 to ∼100 μG. Magnetic fields tend to be strong enough to suppress collapse along much of the bone, but for areas that are most active in star formation, the fields are notably less able to resist gravitational collapse.

Original languageEnglish (US)
Article numberL6
JournalAstrophysical Journal Letters
Issue number1
StatePublished - Feb 1 2022


  • Dense interstellar clouds
  • Dust continuum emission
  • Interstellar dust
  • Interstellar filaments
  • Interstellar magnetic fields
  • Polarimetry
  • Protostars
  • Star formation
  • Young stellar objects

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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