The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence
We present simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cygni at the end of its 2015 outburst. From 2015 July 11-August 5, we monitored V404 Cygni with Chandra, Swift, and NuSTAR in the X-ray, and with the Karl G. Jansky Very Large Array and the Very Long Baseline Ar...
| Main Authors: | , , , , , , , , , , , , , |
|---|---|
| Format: | Journal Article |
| Published: |
Institute of Physics Publishing
2017
|
| Online Access: | http://purl.org/au-research/grants/arc/FT140101082 http://hdl.handle.net/20.500.11937/51213 |
| _version_ | 1848758642106433536 |
|---|---|
| author | Plotkin, Richard Miller-Jones, James Gallo, E. Jonker, P. Homan, J. Tomsick, J. Kaaret, P. Russell, D. Heinz, S. Hodges-Kluck, E. Markoff, S. Sivakoff, G. Altamirano, D. Neilsen, J. |
| author_facet | Plotkin, Richard Miller-Jones, James Gallo, E. Jonker, P. Homan, J. Tomsick, J. Kaaret, P. Russell, D. Heinz, S. Hodges-Kluck, E. Markoff, S. Sivakoff, G. Altamirano, D. Neilsen, J. |
| author_sort | Plotkin, Richard |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We present simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cygni at the end of its 2015 outburst. From 2015 July 11-August 5, we monitored V404 Cygni with Chandra, Swift, and NuSTAR in the X-ray, and with the Karl G. Jansky Very Large Array and the Very Long Baseline Array in the radio, spanning a range of luminosities that were poorly covered during its previous outburst in 1989 (our 2015 campaign covers ). During our 2015 campaign, the X-ray spectrum evolved rapidly from a hard photon index of G ˜ 1.6 (at LX ˜ 10 erg s-34 1) to a softer G ˜ 2 (at L ˜ 3 × 10 erg s- X 33 1). We argue that V404 Cygni reaching marks the beginning of the quiescent spectral state, which occurs at a factor of ˜3-4 higher X-ray luminosity than the average pre-outburst luminosity of . V404 Cygni falls along the same radio/X-ray luminosity correlation that it followed during its previous outburst in 1989, implying a robust disk-jet coupling. We exclude the possibility that a synchrotron-cooled jet dominates the X-ray emission in quiescence, leaving synchrotron self-Compton from either a hot accretion flow or from a radiatively cooled jet as the most likely sources of X-ray radiation, and/or particle acceleration along the jet becoming less efficient in quiescence. Finally, we present the first indications of correlated radio and X-ray variability on minute timescales in quiescence, tentatively measuring the radio emission to lag the X-ray by 15 ± 4minute, suggestive of X-ray variations propagating down a jet with a length of <3.0 au. Copyright © 2017 The American Astronomical Society. All rights reserved. |
| first_indexed | 2025-11-14T09:47:14Z |
| format | Journal Article |
| id | curtin-20.500.11937-51213 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:47:14Z |
| publishDate | 2017 |
| publisher | Institute of Physics Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-512132022-11-28T04:23:20Z The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence Plotkin, Richard Miller-Jones, James Gallo, E. Jonker, P. Homan, J. Tomsick, J. Kaaret, P. Russell, D. Heinz, S. Hodges-Kluck, E. Markoff, S. Sivakoff, G. Altamirano, D. Neilsen, J. We present simultaneous X-ray and radio observations of the black hole X-ray binary V404 Cygni at the end of its 2015 outburst. From 2015 July 11-August 5, we monitored V404 Cygni with Chandra, Swift, and NuSTAR in the X-ray, and with the Karl G. Jansky Very Large Array and the Very Long Baseline Array in the radio, spanning a range of luminosities that were poorly covered during its previous outburst in 1989 (our 2015 campaign covers ). During our 2015 campaign, the X-ray spectrum evolved rapidly from a hard photon index of G ˜ 1.6 (at LX ˜ 10 erg s-34 1) to a softer G ˜ 2 (at L ˜ 3 × 10 erg s- X 33 1). We argue that V404 Cygni reaching marks the beginning of the quiescent spectral state, which occurs at a factor of ˜3-4 higher X-ray luminosity than the average pre-outburst luminosity of . V404 Cygni falls along the same radio/X-ray luminosity correlation that it followed during its previous outburst in 1989, implying a robust disk-jet coupling. We exclude the possibility that a synchrotron-cooled jet dominates the X-ray emission in quiescence, leaving synchrotron self-Compton from either a hot accretion flow or from a radiatively cooled jet as the most likely sources of X-ray radiation, and/or particle acceleration along the jet becoming less efficient in quiescence. Finally, we present the first indications of correlated radio and X-ray variability on minute timescales in quiescence, tentatively measuring the radio emission to lag the X-ray by 15 ± 4minute, suggestive of X-ray variations propagating down a jet with a length of <3.0 au. Copyright © 2017 The American Astronomical Society. All rights reserved. 2017 Journal Article http://hdl.handle.net/20.500.11937/51213 10.3847/1538-4357/834/2/104 http://purl.org/au-research/grants/arc/FT140101082 Institute of Physics Publishing fulltext |
| spellingShingle | Plotkin, Richard Miller-Jones, James Gallo, E. Jonker, P. Homan, J. Tomsick, J. Kaaret, P. Russell, D. Heinz, S. Hodges-Kluck, E. Markoff, S. Sivakoff, G. Altamirano, D. Neilsen, J. The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence |
| title | The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence |
| title_full | The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence |
| title_fullStr | The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence |
| title_full_unstemmed | The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence |
| title_short | The 2015 decay of the black hole X-ray binary V404 Cygni: Robust disk-jet coupling and a sharp transition into quiescence |
| title_sort | 2015 decay of the black hole x-ray binary v404 cygni: robust disk-jet coupling and a sharp transition into quiescence |
| url | http://purl.org/au-research/grants/arc/FT140101082 http://hdl.handle.net/20.500.11937/51213 |