2001/10/31 by S. Lai, Shih-Ping Lai, Richard M. Crutcher +4 · 88 citations
Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Interferometry #Magnetic field #Optics #Physics #Polarization (electrochemistry) #Position angle #Sky #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/338336
published in The Astrophysical Journal 566(2), 925-930 (IOP Publishing) · 10 pages, 5 figures, Accepted for publication in the Astrophysical Journal, Feb 20, 2002 issue
arxiv created 2001/10/31 · openalex publication_date 2002/02/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present the first interferometric polarization maps of the NGC 2024 FIR 5 molecular core, obtained with the BIMA array at approximately 2'' resolution. We measure an average position angle of -60° ± 6° in the main core of FIR 5 and 54° ± 9° in the eastern wing of FIR 5. The morphology of the polarization angles in the main core of FIR 5 suggests that the field lines are parabolic, with a symmetry axis approximately parallel to the major axis of the putative disk in FIR 5, which is consistent with the theoretical scenario that the gravitational collapse pulled the field lines into an hourglass shape. The polarization percentage decreases toward regions with high intensity and close to the center of the core, suggesting that the dust alignment efficiency may decrease at high density. The plane-of-sky field strength can be estimated with the modified Chandrasekhar-Fermi formula, and the small dispersion of the polarization angles in FIR 5 suggests that the magnetic field is strong (≳2 mG) and perhaps dominates the turbulent motions in the core.