Very Large Array Observations of DG Tau's Radio Jet: A Highly Collimated Thermal Outflow

Author(s)

C. Lynch, R. L. Mutel, M. Güdel, Tom Ray, S. L. Skinner, P. C. Schneider, K. G. Gayley

Abstract

The active young protostar DG Tau has an extended jet that has been well

studied at radio, optical, and X-ray wavelengths. We report sensitive

new Very Large Array (VLA) full-polarization observations of the core

and jet between 5 GHz and 8 GHz. Our high angular resolution observation

at 8 GHz clearly shows an unpolarized inner jet with a size of 42 AU

(0.''35) extending along a position angle similar to the optical-X ray

outer jet. Using our nearly coeval 2012 VLA observations, we find a

spectral index α = +0.46 ± 0.05, which combined with the

lack of polarization is consistent with bremsstrahlung (free-free)

emission, with no evidence for a non-thermal coronal component. By

identifying the end of the radio jet as the optical depth unity surface,

and calculating the resulting emission measure, we find that our radio

results are in agreement with previous optical line studies of electron

density and consequent mass-loss rate. We also detect a weak radio knot

at 5 GHz located 7'' from the base of the jet, coincident with the inner

radio knot detected by Rodríguez et al. in 2009 but at lower

surface brightness. We interpret this as due to expansion of post-shock

ionized gas in the three years between observations.

Organisation(s)

Department of Astrophysics

External organisation(s)

Universität Hamburg, University of Colorado, Boulder, University of Iowa, Dublin Institute for Advanced Studies

Journal

The Astrophysical Journal: an international review of astronomy and astronomical physics

Volume

766

No. of pages

8

ISSN

0004-637X

DOI

https://doi.org/10.1088/0004-637X/766/1/53

Publication date

03-2013

Peer reviewed

Yes

Austrian Fields of Science 2012

103004 Astrophysics, 103003 Astronomy

Keywords

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