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Probing the turbulent ambipolar diffusion scale in molecular clouds with spectroscopy

Hezareh, T. and Csengeri, T. and Houde, M. and Herpin, F. and Bontemps, S. (2014) Probing the turbulent ambipolar diffusion scale in molecular clouds with spectroscopy. Monthly Notices of the Royal Astronomical Society, 438 (1). pp. 663-671. ISSN 0035-8711. https://resolver.caltech.edu/CaltechAUTHORS:20140227-160852572

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Abstract

We estimate the turbulent ambipolar diffusion length-scale and magnetic field strength in the massive dense cores CygX-N03 and CygX-N53, located in the Cygnus-X star-forming region. The method we use requires comparing the velocity dispersions in the spectral line profiles of the coexistent ion and neutral pair H13CN and H13CO+ (J = 1 → 0) at different length-scales. We fit Kolmogorov-type power laws to the lower envelopes of the velocity dispersion spectra of the two species. This allows us to calculate the turbulent ambipolar diffusion scale, which in turn determines the plane-of-the-sky magnetic field strength. We find turbulent ambipolar diffusion length-scales of 3.8 ± 0.1 and 21.2 ± 0.4 mpc, and magnetic field strengths of 0.33 and 0.76 mG for CygX-N03 and CygX-N53, respectively. These magnetic field values have uncertainties of a factor of a few. Despite a lower signal-to-noise ratio of the data in CygX-N53 than in CygX-N03, and the caveat that its stronger field might stem in part from projection effects, the difference in field strengths suggests different fragmentation efficiencies of the two cores. Even though the quality of our data, obtained with the Institut de Radio Astronomie Millimetrique (IRAM) Plateau de Bure Interferometer, is somewhat inferior to previous single-dish data, we demonstrate that this method is suited also for observations at high spatial resolution.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1093/mnras/stt2237DOIArticle
http://mnras.oxfordjournals.org/content/438/1/663.abstract?sid=3d4fbeb4-6963-44f8-a1a7-8c10551c5557PublisherArticle
Additional Information:© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 November 14. Received 2013 November 8; in original form 2013 August 18. First published online: December 19, 2013. The authors thank the referee for a careful reading and insightful comments. TH was funded by the Alexander von Humboldt foundation. TC’s contribution was funded by ERC Advanced Investigator Grant GLOSTAR (247078). MH’s research is funded through the NSERC Discovery Grant, Canada Research Chair, Canada Foundation for Innovation and Western’s Academic Development Fund programmes.
Funders:
Funding AgencyGrant Number
Alexander von Humboldt FoundationUNSPECIFIED
ERC Advanced Investigator Grant GLOSTAR247078
NSERC Discovery GrantUNSPECIFIED
Canada Research ChairUNSPECIFIED
Canada Foundation for Innovation (CFI)UNSPECIFIED
Western’s Academic Development Fund programmesUNSPECIFIED
Subject Keywords:line: profiles; turbulence; ISM: clouds; ISM: magnetic fields
Issue or Number:1
Record Number:CaltechAUTHORS:20140227-160852572
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140227-160852572
Official Citation:Hezareh, T., Csengeri, T., Houde, M., Herpin, F., & Bontemps, S. (2014). Probing the turbulent ambipolar diffusion scale in molecular clouds with spectroscopy. Monthly Notices of the Royal Astronomical Society, 438(1), 663-671.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44044
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:28 Feb 2014 15:43
Last Modified:03 Oct 2019 06:13

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