2000/07/01 by Martin Houde, Ruisheng Peng, R. Peng +4 · 62 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atomic and Molecular Physics #Atomic physics #Field (mathematics) #Ion #Line (geometry) #Magnetic field #Molecular cloud #Physics #Spectral line #Stars #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/309035
published in The Astrophysical Journal 537(1), 245-254 (IOP Publishing) · 20 pages, 4 figures, 3 tables
openalex publication_date 2000/07/01 · arxiv created 2003/11/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present further observational evidence in support of our earlier proposal for detecting the presence of the magnetic field in molecular clouds by comparing spectra of molecular ions with those of neutral molecules. The ion lines tend to be narrower and do not show the wings due to flows, when the magnetic field is sufficiently strong. We obtained spectra for the optically thin lines of the H 13 CN and H 13 CO + species in a sample of 10 molecular clouds and found the results to be in agreement with our previous observations of the main isotopic species, HCN and HCO + , made in OMC-1, OMC-2, OMC-3, and DR 21(OH), thus eliminating the possibility of optical depth effects playing a role in the ion line narrowing. HCS + was also detected in four of these star-forming regions. We also discuss previously published results by Benson et al. of N 2 H + detections in a large sample of dark clouds. We show that the similarity in line widths between ion and neutral species in their sample is consistent with the relatively small amount of turbulence and other flows observed in these clouds.