A search for ionized jets towards massive young stellar objects

Purser, S.J.D. and Lumsden, S.L. and Hoare, M.G. and Urquhart, J.S. and Cunningham, N.. and Purcell, C.R. and Brooks, K.J. and Garay, G. and Gúzman, A.E. and Voronkov, M.A. (2016) A search for ionized jets towards massive young stellar objects. Monthly Notices of the Royal Astronomical Society, 460 (1). pp. 1039-1053. ISSN 0035-8711. (doi:https://doi.org/10.1093/mnras/stw1027) (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided)

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Abstract

Radio continuum observations using the Australia telescope compact array at 5.5, 9.0, 17.0 and 22.8 GHz have detected free-free emission associated with 45 of 49 massive young stellar objects and H II regions. Of these, 26 sources are classified as ionized jets (12 of which are candidates), 2 as ambiguous jets or disc winds, 1 as a disc-wind, 14 as H II regions and 2 were unable to be categorized. Classification as ionized jets is based upon morphology, radio flux and spectral index, in conjunction with previous observational results at other wavelengths. Radio luminosity and momentum are found to scale with bolometric luminosity in the same way as low-mass jets, indicating a common mechanism for jet production across all masses. In 13 of the jets, we see associated non-thermal/optically thin lobes resulting from shocks either internal to the jet and/or at working surfaces. 10 jets display non-thermal (synchrotron emission) spectra in their lobes, with an average spectral index of α =-0.55 consistent with Fermi acceleration in shocks. This shows that magnetic fields are present, in agreement with models of jet formation incorporatingmagnetic fields. Since the production of collimated radio jets is associated with accretion processes, the results presented in this paper support the picture of disc-mediated accretion for the formation of massive stars with an upper limit on the jet phase lasting approximately 6.5×104 yr. Typical mass-loss rates in the jet are found to be 1.4× 10-5M⊙ yr-1 with associated momentum rates of the order of (1-2) × 10-2M⊙ km s-1 yr-1. © 2016 The Authors. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Item Type: Article
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Mon. Not. R. Astron. Soc. [Field not mapped to EPrints] AD - School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom [Field not mapped to EPrints] AD - Max-Planck-Institute für Radioastronomie, Auf dem Hügel 69, Bonn, Germany [Field not mapped to EPrints] AD - Centre for Astrophysics and Planetary Science, The University of Kent, Canterbury, Kent, United Kingdom [Field not mapped to EPrints] AD - National Radio Astronomy Observatory, PO Box 2, Green Bank, WV, United States [Field not mapped to EPrints] AD - Sydney Institute for Astronomy (SIfA), School of Physics, The University of SydneyNSW, Australia [Field not mapped to EPrints] AD - Australia Telescope National Facility, CSIRO Astronomy and Space Science, PO Box 76, Epping, NSW, Australia [Field not mapped to EPrints] AD - Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints] M3 - Article [Field not mapped to EPrints]
Uncontrolled keywords: ISM: jets and outflows, Radio continuum: ISM, Stars: evolution, Stars: formation, Stars: massive, Stars: protostars
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: James Urquhart
Date Deposited: 10 Oct 2016 09:19 UTC
Last Modified: 29 May 2018 15:22 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/57821 (The current URI for this page, for reference purposes)
Urquhart, J.S.: https://orcid.org/0000-0002-1605-8050
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