A transient relativistic radio jet from Cygnus X-1
We report the first observation of a transient relativistic jet from the canonical black hole candidate, Cygnus X-1, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN). The jet was observed in only one of six epochs of MERLIN imaging of the source during a phase of repeated...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
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Wiley-Blackwell Publishing Ltd.
2006
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| Online Access: | http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2006.10193.x/full http://hdl.handle.net/20.500.11937/16391 |
| _version_ | 1848749163730173952 |
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| author | Fender, R. Stirling, A. Spencer, R. Brown, I. Pooley, G. Muxlow, T. Miller-Jones, James |
| author_facet | Fender, R. Stirling, A. Spencer, R. Brown, I. Pooley, G. Muxlow, T. Miller-Jones, James |
| author_sort | Fender, R. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We report the first observation of a transient relativistic jet from the canonical black hole candidate, Cygnus X-1, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN). The jet was observed in only one of six epochs of MERLIN imaging of the source during a phase of repeated X-ray spectral transitions in 2004 Jan–Feb, and this epoch corresponded to the softest 1.5–12 keV X-ray spectrum. With only a single epoch revealing the jet, we cannot formally constrain its velocity. Nevertheless, several lines of reasoning suggest that the jet was probably launched 0.5–4.0 d before this brightening, corresponding to projected velocities of 0.2c?vapp? 1.6c, and an intrinsic velocity of ?0.3c. We also report the occurrence of a major radio flare from Cyg X-1, reaching a flux density of ~120 mJy at 15 GHz, and yet not associated with any resolvable radio emission, despite a concerted effort with MERLIN. We discuss the resolved jet in terms of the recently proposed ‘unified model’ for the disc–jet coupling in black hole X-ray binaries, and tentatively identify the ‘jet line’ for Cyg X-1. The source is consistent with the model in the sense that a steady jet appears to persist initially when the X-ray spectrum starts softening, and that once the spectral softening is complete the core radio emission is suppressed and transient ejecta/shock observed. However, there are some anomalies, and Cyg X-1 clearly does not behave like a normal black hole transient in progressing to the canonical soft/thermal state once the ejection event has happened. |
| first_indexed | 2025-11-14T07:16:34Z |
| format | Journal Article |
| id | curtin-20.500.11937-16391 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:16:34Z |
| publishDate | 2006 |
| publisher | Wiley-Blackwell Publishing Ltd. |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-163912019-02-19T04:25:52Z A transient relativistic radio jet from Cygnus X-1 Fender, R. Stirling, A. Spencer, R. Brown, I. Pooley, G. Muxlow, T. Miller-Jones, James accretion black hole physics accretion discs X-rays: binaries accretion discs: black hole physics: ISM: jets and outflows: X-rays: binaries ISM: jets and outflows We report the first observation of a transient relativistic jet from the canonical black hole candidate, Cygnus X-1, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN). The jet was observed in only one of six epochs of MERLIN imaging of the source during a phase of repeated X-ray spectral transitions in 2004 Jan–Feb, and this epoch corresponded to the softest 1.5–12 keV X-ray spectrum. With only a single epoch revealing the jet, we cannot formally constrain its velocity. Nevertheless, several lines of reasoning suggest that the jet was probably launched 0.5–4.0 d before this brightening, corresponding to projected velocities of 0.2c?vapp? 1.6c, and an intrinsic velocity of ?0.3c. We also report the occurrence of a major radio flare from Cyg X-1, reaching a flux density of ~120 mJy at 15 GHz, and yet not associated with any resolvable radio emission, despite a concerted effort with MERLIN. We discuss the resolved jet in terms of the recently proposed ‘unified model’ for the disc–jet coupling in black hole X-ray binaries, and tentatively identify the ‘jet line’ for Cyg X-1. The source is consistent with the model in the sense that a steady jet appears to persist initially when the X-ray spectrum starts softening, and that once the spectral softening is complete the core radio emission is suppressed and transient ejecta/shock observed. However, there are some anomalies, and Cyg X-1 clearly does not behave like a normal black hole transient in progressing to the canonical soft/thermal state once the ejection event has happened. 2006 Journal Article http://hdl.handle.net/20.500.11937/16391 http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2006.10193.x/full Wiley-Blackwell Publishing Ltd. restricted |
| spellingShingle | accretion black hole physics accretion discs X-rays: binaries accretion discs: black hole physics: ISM: jets and outflows: X-rays: binaries ISM: jets and outflows Fender, R. Stirling, A. Spencer, R. Brown, I. Pooley, G. Muxlow, T. Miller-Jones, James A transient relativistic radio jet from Cygnus X-1 |
| title | A transient relativistic radio jet from Cygnus X-1 |
| title_full | A transient relativistic radio jet from Cygnus X-1 |
| title_fullStr | A transient relativistic radio jet from Cygnus X-1 |
| title_full_unstemmed | A transient relativistic radio jet from Cygnus X-1 |
| title_short | A transient relativistic radio jet from Cygnus X-1 |
| title_sort | transient relativistic radio jet from cygnus x-1 |
| topic | accretion black hole physics accretion discs X-rays: binaries accretion discs: black hole physics: ISM: jets and outflows: X-rays: binaries ISM: jets and outflows |
| url | http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2006.10193.x/full http://hdl.handle.net/20.500.11937/16391 |