Magnetic Fields at the Periphery of Ultracompact H ii Regions from Carbon Recombination Line Observations
Author(s) -
D. Anish Roshi
Publication year - 2007
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/513465
Subject(s) - recombination , magnetic field , line (geometry) , astrophysics , line width , photodissociation , physics , spectral line , molecular cloud , atomic physics , field (mathematics) , molecular physics , chemistry , astronomy , optics , photochemistry , geometry , gene , biochemistry , mathematics , stars , quantum mechanics , pure mathematics
Several indirect evidences indicate a magnetic origin for the non-thermalwidth of spectral lines observed toward molecular clouds. In this letter, Isuggest that the origin of the non-thermal width of carbon recombination lines(CRLs) observed from photo-dissociation regions (PDRs) near ultra-compact \HII\regions is magnetic and that the magnitude of the line width is an estimate ofthe \alfven speed. The magnetic field strengths estimated based on thissuggestion compare well with those measured toward molecular clouds withdensities similar to PDR densities. I conclude that multi-frequency CRLobservations have the potential to form a new tool to determine the fieldstrength near star forming regions.Comment: To appear in ApJ Letter
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