The first resolved imaging of milliarcsecond-scale jets in Circinus X-1

J. C.A. Miller-Jones, A. Moin, S. J. Tingay, C. Reynolds, C. J. Phillips, A. K. Tzioumis, R. P. Fender, J. N. Mccallum, G. D. Nicolson, V. Tudose

Research output: Contribution to journalLetterpeer-review

18 Citations (Scopus)


We present the first resolved imaging of the milliarcsecond-scale jets in the neutron star X-ray binary Circinus X-1, made using the Australian Long Baseline Array. The angular extent of the resolved jets is ∼20mas, corresponding to a physical scale of ∼150au at the assumed distance of 7.8kpc. The jet position angle is relatively consistent with previous arcsecond-scale imaging with the Australia Telescope Compact Array. The radio emission is symmetric about the peak, and is unresolved along the minor axis, constraining the opening angle to be <20°. We observe evidence for outward motion of the components between the two halves of the observation. Constraints on the proper motion of the radio-emitting components suggest that they are only mildly relativistic, although we cannot definitively rule out the presence of the unseen, ultrarelativistic (Γ > 15) flow previously inferred to exist in this system.

Original languageEnglish
Pages (from-to)L49-L53
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
Publication statusPublished - Jan 2012
Externally publishedYes


  • ISM: jets and outflows
  • Radio continuum: stars
  • Stars: individual: Circinus X-1
  • X-rays: binaries

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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