First results from MASIV: The microarcsecond scintillation-induced variability survey
We are undertaking a large-scale, microarcsecond scintillation-induced variability survey, MASIV, of the northern sky (decl. > 0°) at 4.9 GHz with the VLA. Our objective is to construct a sample of 100 to 150 scintillating extragalactic sources with which to examine both the microarcsecond struct...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Published: |
Institute of Physics Publishing, Inc
2003
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/22903 |
| _version_ | 1848751002830766080 |
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| author | Lovell, J. Jauncey, D. Bignall, Hayley Kedziora-Chudczer, L. Macquart, Jean-Pierre Rickett, B.J. Tzioumis, A. |
| author_facet | Lovell, J. Jauncey, D. Bignall, Hayley Kedziora-Chudczer, L. Macquart, Jean-Pierre Rickett, B.J. Tzioumis, A. |
| author_sort | Lovell, J. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We are undertaking a large-scale, microarcsecond scintillation-induced variability survey, MASIV, of the northern sky (decl. > 0°) at 4.9 GHz with the VLA. Our objective is to construct a sample of 100 to 150 scintillating extragalactic sources with which to examine both the microarcsecond structure and the parent populations of these sources, and to probe the turbulent interstellar medium responsible for the scintillation. We report on our first epoch of observations, which revealed variability on timescales ranging from hours to days in 85 of 710 compact flat-spectrum sources. The number of highly variable sources, those with rms flux density variations greater than 4% of the mean, increases with decreasing source flux density, but rapid, large amplitude variables such as J1819+3845 are very rare. When compared with a model for the scintillation due to irregularities in an electron layer 500 pc thick, our preliminary results indicate maximum brightness temperatures 1012 K, similar to those obtained from VLBI surveys even though interstellar scintillation is not subject to the same angular resolution limit. |
| first_indexed | 2025-11-14T07:45:48Z |
| format | Journal Article |
| id | curtin-20.500.11937-22903 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:45:48Z |
| publishDate | 2003 |
| publisher | Institute of Physics Publishing, Inc |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-229032023-02-22T06:24:23Z First results from MASIV: The microarcsecond scintillation-induced variability survey Lovell, J. Jauncey, D. Bignall, Hayley Kedziora-Chudczer, L. Macquart, Jean-Pierre Rickett, B.J. Tzioumis, A. ISM: structure radio continuum galaxies: active We are undertaking a large-scale, microarcsecond scintillation-induced variability survey, MASIV, of the northern sky (decl. > 0°) at 4.9 GHz with the VLA. Our objective is to construct a sample of 100 to 150 scintillating extragalactic sources with which to examine both the microarcsecond structure and the parent populations of these sources, and to probe the turbulent interstellar medium responsible for the scintillation. We report on our first epoch of observations, which revealed variability on timescales ranging from hours to days in 85 of 710 compact flat-spectrum sources. The number of highly variable sources, those with rms flux density variations greater than 4% of the mean, increases with decreasing source flux density, but rapid, large amplitude variables such as J1819+3845 are very rare. When compared with a model for the scintillation due to irregularities in an electron layer 500 pc thick, our preliminary results indicate maximum brightness temperatures 1012 K, similar to those obtained from VLBI surveys even though interstellar scintillation is not subject to the same angular resolution limit. 2003 Journal Article http://hdl.handle.net/20.500.11937/22903 10.1086/378053 Institute of Physics Publishing, Inc unknown |
| spellingShingle | ISM: structure radio continuum galaxies: active Lovell, J. Jauncey, D. Bignall, Hayley Kedziora-Chudczer, L. Macquart, Jean-Pierre Rickett, B.J. Tzioumis, A. First results from MASIV: The microarcsecond scintillation-induced variability survey |
| title | First results from MASIV: The microarcsecond scintillation-induced variability survey |
| title_full | First results from MASIV: The microarcsecond scintillation-induced variability survey |
| title_fullStr | First results from MASIV: The microarcsecond scintillation-induced variability survey |
| title_full_unstemmed | First results from MASIV: The microarcsecond scintillation-induced variability survey |
| title_short | First results from MASIV: The microarcsecond scintillation-induced variability survey |
| title_sort | first results from masiv: the microarcsecond scintillation-induced variability survey |
| topic | ISM: structure radio continuum galaxies: active |
| url | http://hdl.handle.net/20.500.11937/22903 |