A polarization survey of bright extragalactic AT20G sources
We present polarization data for 180 extragalactic sources extracted from the Australia Telescope 20 GHz (AT20G) survey catalogue and observed with the Australia Telescope Compact Array during a dedicated, high sensitivity run (sP ~ 1mJy). For the sake of completeness, we extracted the polarization...
| Main Authors: | , , , , , , , , , , |
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| Format: | Journal Article |
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2013
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| Online Access: | http://hdl.handle.net/20.500.11937/32392 |
| _version_ | 1848753650782961664 |
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| author | Massardi, M. Burke-Spolaor, S. Murphy, T. Ricci, R. López-Caniego, M. Negrello, M. Chhetri, R. De Zotti, G. Ekers, Ronald Partridge, R. Sadler, E. |
| author_facet | Massardi, M. Burke-Spolaor, S. Murphy, T. Ricci, R. López-Caniego, M. Negrello, M. Chhetri, R. De Zotti, G. Ekers, Ronald Partridge, R. Sadler, E. |
| author_sort | Massardi, M. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We present polarization data for 180 extragalactic sources extracted from the Australia Telescope 20 GHz (AT20G) survey catalogue and observed with the Australia Telescope Compact Array during a dedicated, high sensitivity run (sP ~ 1mJy). For the sake of completeness, we extracted the polarization information for seven extended sources from the 9 yr Wilkinson Microwave Anisotropy Probe co-added maps at 23 GHz. The full sample of 187 sources constitutes a ?99 per cent complete sample of extragalactic sources brighter than S20GHz = 500 mJy at the selection epoch with declinationd < -30°. The sample has a 91.4 per cent detection rate in polarization at ~20 GHz (94 per cent if considering the subsample of point-like sources). We have measurements also at 4.8 and 8.6 GHz within ~1 month of the 20 GHz observations for 172 sources to reconstruct the spectral properties of the sample in total intensity and in polarization: 143 of them have a polarization detection at all three frequencies. We find that there is no statistically significant evidence of a relationship either between the fraction of polarization and frequency or between the fraction of polarization and the total intensity flux density. This indicates that Faraday depolarization is not very important above 4.8 GHz and that the magnetic field is not substantially more ordered in the regions dominating the emission at higher frequencies (up to 20 GHz).We estimate the distribution of the polarization fraction and the polarized flux density source counts at ~20 GHz. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. |
| first_indexed | 2025-11-14T08:27:54Z |
| format | Journal Article |
| id | curtin-20.500.11937-32392 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:27:54Z |
| publishDate | 2013 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-323922017-09-13T15:23:55Z A polarization survey of bright extragalactic AT20G sources Massardi, M. Burke-Spolaor, S. Murphy, T. Ricci, R. López-Caniego, M. Negrello, M. Chhetri, R. De Zotti, G. Ekers, Ronald Partridge, R. Sadler, E. We present polarization data for 180 extragalactic sources extracted from the Australia Telescope 20 GHz (AT20G) survey catalogue and observed with the Australia Telescope Compact Array during a dedicated, high sensitivity run (sP ~ 1mJy). For the sake of completeness, we extracted the polarization information for seven extended sources from the 9 yr Wilkinson Microwave Anisotropy Probe co-added maps at 23 GHz. The full sample of 187 sources constitutes a ?99 per cent complete sample of extragalactic sources brighter than S20GHz = 500 mJy at the selection epoch with declinationd < -30°. The sample has a 91.4 per cent detection rate in polarization at ~20 GHz (94 per cent if considering the subsample of point-like sources). We have measurements also at 4.8 and 8.6 GHz within ~1 month of the 20 GHz observations for 172 sources to reconstruct the spectral properties of the sample in total intensity and in polarization: 143 of them have a polarization detection at all three frequencies. We find that there is no statistically significant evidence of a relationship either between the fraction of polarization and frequency or between the fraction of polarization and the total intensity flux density. This indicates that Faraday depolarization is not very important above 4.8 GHz and that the magnetic field is not substantially more ordered in the regions dominating the emission at higher frequencies (up to 20 GHz).We estimate the distribution of the polarization fraction and the polarized flux density source counts at ~20 GHz. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. 2013 Journal Article http://hdl.handle.net/20.500.11937/32392 10.1093/mnras/stt1717 unknown |
| spellingShingle | Massardi, M. Burke-Spolaor, S. Murphy, T. Ricci, R. López-Caniego, M. Negrello, M. Chhetri, R. De Zotti, G. Ekers, Ronald Partridge, R. Sadler, E. A polarization survey of bright extragalactic AT20G sources |
| title | A polarization survey of bright extragalactic AT20G sources |
| title_full | A polarization survey of bright extragalactic AT20G sources |
| title_fullStr | A polarization survey of bright extragalactic AT20G sources |
| title_full_unstemmed | A polarization survey of bright extragalactic AT20G sources |
| title_short | A polarization survey of bright extragalactic AT20G sources |
| title_sort | polarization survey of bright extragalactic at20g sources |
| url | http://hdl.handle.net/20.500.11937/32392 |