Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure
We report measurements of time delays of up to 8 minutes in the centimeter-wavelength variability patterns of the intrahour scintillating quasar PKS 1257326, as observed between the VLA and the ATCA on three separate epochs. These time delays confirm interstellar scintillation as the mechanism respo...
| Main Authors: | , , , , , |
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| Format: | Journal Article |
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The American Astronomical Society
2006
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| Online Access: | http://hdl.handle.net/20.500.11937/6560 |
| _version_ | 1848745110990225408 |
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| author | Bignall, Hayley Macquart, Jean-Pierre Jauncey, D. Lovell, J. Tzioumis, A. Kedziora-Chudczer, L. |
| author_facet | Bignall, Hayley Macquart, Jean-Pierre Jauncey, D. Lovell, J. Tzioumis, A. Kedziora-Chudczer, L. |
| author_sort | Bignall, Hayley |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We report measurements of time delays of up to 8 minutes in the centimeter-wavelength variability patterns of the intrahour scintillating quasar PKS 1257326, as observed between the VLA and the ATCA on three separate epochs. These time delays confirm interstellar scintillation as the mechanism responsible for the rapid variability, at the same time effectively ruling out the coexistence of intrinsic intrahour variability in this source. The time delays are combined with measurements of the annual variation in variability timescale exhibited by this source to determine the characteristic length scale and anisotropy of the quasar’s intensity-scintillation pattern, as well as to attempt to fit forthe bulk velocity of the scattering plasma responsible for the scintillation.We find evidence for anisotropic scattering and highly elongated scintillation patterns at both 4.9 and 8.5 GHz, with an axial ratio >10 :1, extended in a northwest direction on the sky. The characteristic scale of the scintillation pattern along its minor axis is well determined, but the high anisotropy leads to degenerate solutions for the scintillation velocity. The decorrelation of the pattern over the baseline gives an estimate of the major-axis length scale of the scintillation pattern.We derive an upper limit on the distance to the scattering plasma of no more than 10 pc. |
| first_indexed | 2025-11-14T06:12:09Z |
| format | Journal Article |
| id | curtin-20.500.11937-6560 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:12:09Z |
| publishDate | 2006 |
| publisher | The American Astronomical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-65602023-02-22T06:24:23Z Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure Bignall, Hayley Macquart, Jean-Pierre Jauncey, D. Lovell, J. Tzioumis, A. Kedziora-Chudczer, L. ISM: structure quasars: individual (PKS 1257326) - scattering radio continuum: galaxies We report measurements of time delays of up to 8 minutes in the centimeter-wavelength variability patterns of the intrahour scintillating quasar PKS 1257326, as observed between the VLA and the ATCA on three separate epochs. These time delays confirm interstellar scintillation as the mechanism responsible for the rapid variability, at the same time effectively ruling out the coexistence of intrinsic intrahour variability in this source. The time delays are combined with measurements of the annual variation in variability timescale exhibited by this source to determine the characteristic length scale and anisotropy of the quasar’s intensity-scintillation pattern, as well as to attempt to fit forthe bulk velocity of the scattering plasma responsible for the scintillation.We find evidence for anisotropic scattering and highly elongated scintillation patterns at both 4.9 and 8.5 GHz, with an axial ratio >10 :1, extended in a northwest direction on the sky. The characteristic scale of the scintillation pattern along its minor axis is well determined, but the high anisotropy leads to degenerate solutions for the scintillation velocity. The decorrelation of the pattern over the baseline gives an estimate of the major-axis length scale of the scintillation pattern.We derive an upper limit on the distance to the scattering plasma of no more than 10 pc. 2006 Journal Article http://hdl.handle.net/20.500.11937/6560 10.1086/508406 The American Astronomical Society unknown |
| spellingShingle | ISM: structure quasars: individual (PKS 1257326) - scattering radio continuum: galaxies Bignall, Hayley Macquart, Jean-Pierre Jauncey, D. Lovell, J. Tzioumis, A. Kedziora-Chudczer, L. Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| title | Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| title_full | Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| title_fullStr | Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| title_full_unstemmed | Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| title_short | Rapid interstellar scintillation of PKS 1257-326: Two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| title_sort | rapid interstellar scintillation of pks 1257-326: two-station pattern time delays and constraints on scattering and microarcsecond source structure |
| topic | ISM: structure quasars: individual (PKS 1257326) - scattering radio continuum: galaxies |
| url | http://hdl.handle.net/20.500.11937/6560 |