PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752
We present 18 GHz Australia Telescope Compact Array imaging of the megaparsec-scale quasar jet PKS 0637–752 with angular resolution ~0[" over .]58. We draw attention to a spectacular train of quasi-periodic knots along the inner 11'' of the jet, with average separation ~1.1 arcsec (7....
| Main Authors: | , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/95508 |
| _version_ | 1826211492022714368 |
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| author | Godfrey, L. E. H. Lovell, J. E. J. Burke-Spolaor, S. Ekers, R. Bicknell, G. V. Birkinshaw, M. Worrall, D. M. Jauncey, D. L. Schwartz, D. A. Gelbord, Jonathan Perlman, E. S. Georganopoulos, Markos Marshall, Herman |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Godfrey, L. E. H. Lovell, J. E. J. Burke-Spolaor, S. Ekers, R. Bicknell, G. V. Birkinshaw, M. Worrall, D. M. Jauncey, D. L. Schwartz, D. A. Gelbord, Jonathan Perlman, E. S. Georganopoulos, Markos Marshall, Herman |
| author_sort | Godfrey, L. E. H. |
| collection | MIT |
| description | We present 18 GHz Australia Telescope Compact Array imaging of the megaparsec-scale quasar jet PKS 0637–752 with angular resolution ~0[" over .]58. We draw attention to a spectacular train of quasi-periodic knots along the inner 11'' of the jet, with average separation ~1.1 arcsec (7.6 kpc projected). We consider two classes of model to explain the periodic knots: those that involve a static pattern through which the jet plasma travels (e.g., stationary shocks) and those that involve modulation of the jet engine. Interpreting the knots as re-confinement shocks implies the jet kinetic power Q [subscript jet] ~ 10[superscript 46] erg s[superscript –1], but the constant knot separation along the jet is not expected in a realistic external density profile. For models involving modulation of the jet engine, we find that the required modulation period is 2 × 10[superscript 3] yr < τ < 3 × 10[superscript 5] yr. The lower end of this range is applicable if the jet remains highly relativistic on kiloparsec scales, as implied by the IC/CMB model of jet X-ray emission. We suggest that the periodic jet structure in PKS 0637–752 may be analogous to the quasi-periodic jet modulation seen in the microquasar GRS 1915+105, believed to result from limit cycle behavior in an unstable accretion disk. If variations in the accretion rate are driven by a binary black hole, the predicted orbital radius is 0.7 pc [< over ~] a [< over ~] 30 pc, which corresponds to a maximum angular separation of ~0.1-5 mas. |
| first_indexed | 2024-09-23T15:07:09Z |
| format | Article |
| id | mit-1721.1/95508 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:07:09Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/955082022-10-02T00:40:03Z PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 Godfrey, L. E. H. Lovell, J. E. J. Burke-Spolaor, S. Ekers, R. Bicknell, G. V. Birkinshaw, M. Worrall, D. M. Jauncey, D. L. Schwartz, D. A. Gelbord, Jonathan Perlman, E. S. Georganopoulos, Markos Marshall, Herman MIT Kavli Institute for Astrophysics and Space Research Marshall, Herman Lee We present 18 GHz Australia Telescope Compact Array imaging of the megaparsec-scale quasar jet PKS 0637–752 with angular resolution ~0[" over .]58. We draw attention to a spectacular train of quasi-periodic knots along the inner 11'' of the jet, with average separation ~1.1 arcsec (7.6 kpc projected). We consider two classes of model to explain the periodic knots: those that involve a static pattern through which the jet plasma travels (e.g., stationary shocks) and those that involve modulation of the jet engine. Interpreting the knots as re-confinement shocks implies the jet kinetic power Q [subscript jet] ~ 10[superscript 46] erg s[superscript –1], but the constant knot separation along the jet is not expected in a realistic external density profile. For models involving modulation of the jet engine, we find that the required modulation period is 2 × 10[superscript 3] yr < τ < 3 × 10[superscript 5] yr. The lower end of this range is applicable if the jet remains highly relativistic on kiloparsec scales, as implied by the IC/CMB model of jet X-ray emission. We suggest that the periodic jet structure in PKS 0637–752 may be analogous to the quasi-periodic jet modulation seen in the microquasar GRS 1915+105, believed to result from limit cycle behavior in an unstable accretion disk. If variations in the accretion rate are driven by a binary black hole, the predicted orbital radius is 0.7 pc [< over ~] a [< over ~] 30 pc, which corresponds to a maximum angular separation of ~0.1-5 mas. 2015-02-25T15:31:46Z 2015-02-25T15:31:46Z 2012-09 2012-07 Article http://purl.org/eprint/type/JournalArticle 2041-8205 2041-8213 http://hdl.handle.net/1721.1/95508 Godfrey, L. E. H., J. E. J. Lovell, S. Burke-Spolaor, R. Ekers, G. V. Bicknell, M. Birkinshaw, D. M. Worrall, et al. “PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752.” The Astrophysical Journal 758, no. 2 (September 27, 2012): L27. © 2012 The American Astronomical Society en_US http://dx.doi.org/10.1088/2041-8205/758/2/l27 The Astrophysical Journal. Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing American Astronomical Society |
| spellingShingle | Godfrey, L. E. H. Lovell, J. E. J. Burke-Spolaor, S. Ekers, R. Bicknell, G. V. Birkinshaw, M. Worrall, D. M. Jauncey, D. L. Schwartz, D. A. Gelbord, Jonathan Perlman, E. S. Georganopoulos, Markos Marshall, Herman PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 |
| title | PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 |
| title_full | PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 |
| title_fullStr | PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 |
| title_full_unstemmed | PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 |
| title_short | PERIODIC STRUCTURE IN THE MEGAPARSEC-SCALE JET OF PKS 0637–752 |
| title_sort | periodic structure in the megaparsec scale jet of pks 0637 752 |
| url | http://hdl.handle.net/1721.1/95508 |
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