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dc.contributor.authorRushton, A.
dc.contributor.authorMiller-Jones, James
dc.contributor.authorCampana, R.
dc.contributor.authorEvangelista, Y.
dc.contributor.authorParagi, Z.
dc.contributor.authorMaccarone, T.
dc.contributor.authorPooley, G.
dc.contributor.authorTudose, V.
dc.contributor.authorFender, R.
dc.contributor.authorSpencer, R.
dc.contributor.authorDhawan, V.
dc.date.accessioned2017-01-30T11:55:23Z
dc.date.available2017-01-30T11:55:23Z
dc.date.created2015-03-03T20:17:46Z
dc.date.issued2012
dc.identifier.citationRushton, A. and Miller-Jones, J. and Campana, R. and Evangelista, Y. and Paragi, Z. and Maccarone, T. and Pooley, G. et al. 2012. A weak compact jet in a soft state of Cygnus X-1. Monthly Notices of the Royal Astronomical Society. 419 (4): pp. 3194-3199.
dc.identifier.urihttp://hdl.handle.net/20.500.11937/16360
dc.identifier.doi10.1111/j.1365-2966.2011.19959.x
dc.description.abstract

We present evidence for the presence of a weak compact jet during a soft X-ray state of Cygnus X-1. Very-high-resolution radio observations were taken with the VLBA, EVN and MERLIN during a hard-to-soft spectral state change, showing the hard state jet to be suppressed by a factor of about 3–5 in radio flux and unresolved to direct imaging observations (i.e. ≤1 mas at 4 cm). High time-resolution X-ray observations with the RXTE-PCA were also taken during the radio monitoring period, showing the source to make the transition from the hard state to a softer state (via an intermediate state), although the source may never have reached the canonical soft state. Using astrometric very long baseline interferometry (VLBI) analysis and removing proper motion, parallax and orbital motion signatures, the residual positions show a scatter of ~0.2 mas (at 4 cm) and ∼3 mas (at 13cm) along the position angle of the known jet axis; these residuals suggest that there is a weak unresolved outflow, with varying size or opacity, during intermediate and soft X-ray states. Furthermore, no evidence was found for extended knots or shocks forming within the jet during the state transition, suggesting that the change in outflow rate may not be sufficiently high to produce superluminal knots.

dc.publisherWiley-Blackwell Publishing Ltd.
dc.subjectstars: individual: Cygnus X-1
dc.subjectX-rays: binaries
dc.subjectISM: jets and outflows
dc.titleA weak compact jet in a soft state of Cygnus X-1
dc.typeJournal Article
dcterms.source.volume419
dcterms.source.number4
dcterms.source.startPage3194
dcterms.source.endPage3199
dcterms.source.issn1365-2966
dcterms.source.titleMonthly Notices of the Royal Astronomical Society
curtin.note

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society, ©: 2011, the authors and the Royal Astronomical Society. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

curtin.departmentCurtin Institute of Radio Astronomy (Physics)
curtin.accessStatusOpen access


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