SIMBAD references

2016ApJ...816...22B - Astrophys. J., 816, 22 (2016/January-1)

Magnetic field strengths in photodissociation regions.

BALSER D.S., ROSHI D.A., JEYAKUMAR S., BANIA T.M., MONTET B.T. and SHITANISHI J.A.

Abstract (from CDS):

We measure carbon radio recombination line (RRL) emission at 5.3 GHz toward four H ii regions with the Green Bank Telescope to determine the magnetic field strength in the photodissociation region (PDR) that surrounds the ionized gas. Roshi suggests that the non-thermal line widths of carbon RRLs from PDRs are predominantly due to magneto-hydrodynamic waves, thus allowing the magnetic field strength to be derived. We model the PDR with a simple geometry and perform the non-LTE radiative transfer of the carbon RRL emission to solve for the PDR physical properties. Using the PDR mass density from these models and the carbon RRL non-thermal line width we estimate total magnetic field strengths of B ∼ 100-300 µG in W3 and NGC 6334A. Our results for W49 and NGC 6334D are less well constrained with total magnetic field strengths between B ∼ 200-1000µG. H i and OH Zeeman measurements of the line of sight magnetic field strength (Blos), taken from the literature, are between a factor of ∼0.5-1 of the lower bound of our carbon RRL magnetic field strength estimates. Since |B_los| ≤ B, our results are consistent with the magnetic origin of the non-thermal component of carbon RRL widths.

Abstract Copyright:

Journal keyword(s): H ii regions - ISM: general - ISM: magnetic fields - photon-dominated region, PDR - radio lines: ISM

Simbad objects: 11

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2019.09.18-23:11:09

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