The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array
We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A’s giant radio lobes. We compare our images to 1.4 GHz maps of Cen A and co...
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| Format: | Journal Article |
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Oxford University Press
2013
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/42187 |
| _version_ | 1848756350950047744 |
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| author | McKinley, B. Briggs, F. Gaensler, B. Feain, I. Bernardi, G. Wayth, Randall Johnston-Hollitt, M. Offringa, A. Arcus, Wayne Barnes, D. Bowman, J. Bunton, J. Capallo, R. Corey, B. Deshpande, A. deSouza, L. Emrich, David Goeke, R. Greenhill, L. Hazelton, B. Herne, David Hewitt, J. Kaplan, David Kasper, J. Kincaid, B. Koenig, R. Kratzenberg, E. Lonsdale, C. Lynch, Mervyn McWhirter, S. Mitchell, D. Morales, M. Morgan, E. Oberoi, D. Ord, Stephen Pathikulangara, J. Prabu, T. Remillard, R. Rogers, A. Roshi, D. Salah, J. Sault, R. Udaya Shankar, N. Srivani, K. Stevens, J. Subrahmanyan, R. Tingay, Steven Waterson, Mark Webster, R. Whitney, A. Williams, Andrew Williams, C. Wyithe, J. |
| author_facet | McKinley, B. Briggs, F. Gaensler, B. Feain, I. Bernardi, G. Wayth, Randall Johnston-Hollitt, M. Offringa, A. Arcus, Wayne Barnes, D. Bowman, J. Bunton, J. Capallo, R. Corey, B. Deshpande, A. deSouza, L. Emrich, David Goeke, R. Greenhill, L. Hazelton, B. Herne, David Hewitt, J. Kaplan, David Kasper, J. Kincaid, B. Koenig, R. Kratzenberg, E. Lonsdale, C. Lynch, Mervyn McWhirter, S. Mitchell, D. Morales, M. Morgan, E. Oberoi, D. Ord, Stephen Pathikulangara, J. Prabu, T. Remillard, R. Rogers, A. Roshi, D. Salah, J. Sault, R. Udaya Shankar, N. Srivani, K. Stevens, J. Subrahmanyan, R. Tingay, Steven Waterson, Mark Webster, R. Whitney, A. Williams, Andrew Williams, C. Wyithe, J. |
| author_sort | McKinley, B. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A’s giant radio lobes. We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature–temperature plots and spectral tomography. We find that the morphologies at 118MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr. |
| first_indexed | 2025-11-14T09:10:49Z |
| format | Journal Article |
| id | curtin-20.500.11937-42187 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:10:49Z |
| publishDate | 2013 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-421872017-09-13T16:08:35Z The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array McKinley, B. Briggs, F. Gaensler, B. Feain, I. Bernardi, G. Wayth, Randall Johnston-Hollitt, M. Offringa, A. Arcus, Wayne Barnes, D. Bowman, J. Bunton, J. Capallo, R. Corey, B. Deshpande, A. deSouza, L. Emrich, David Goeke, R. Greenhill, L. Hazelton, B. Herne, David Hewitt, J. Kaplan, David Kasper, J. Kincaid, B. Koenig, R. Kratzenberg, E. Lonsdale, C. Lynch, Mervyn McWhirter, S. Mitchell, D. Morales, M. Morgan, E. Oberoi, D. Ord, Stephen Pathikulangara, J. Prabu, T. Remillard, R. Rogers, A. Roshi, D. Salah, J. Sault, R. Udaya Shankar, N. Srivani, K. Stevens, J. Subrahmanyan, R. Tingay, Steven Waterson, Mark Webster, R. Whitney, A. Williams, Andrew Williams, C. Wyithe, J. techniques: interferometric – galaxies: active – galaxies: individual: NGC 5128 – radio continuum: galaxies We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A’s giant radio lobes. We compare our images to 1.4 GHz maps of Cen A and compute spectral indices using temperature–temperature plots and spectral tomography. We find that the morphologies at 118MHz and 1.4 GHz match very closely apart from an extra peak in the southern lobe at 118 MHz, which provides tentative evidence for the existence of a southern counterpart to the northern middle lobe of Cen A. Our spatially averaged spectral indices for both the northern and southern lobes are consistent with previous analyses, however we find significant spatial variation of the spectra across the extent of each lobe. Both the spectral-index distribution and the morphology at low radio frequencies support a scenario of multiple outbursts of activity from the central engine. Our results are consistent with inverse-Compton modelling of radio and gamma-ray data that support a value for the lobe age of between 10 and 80 Myr. 2013 Journal Article http://hdl.handle.net/20.500.11937/42187 10.1093/mnras/stt1662 Oxford University Press fulltext |
| spellingShingle | techniques: interferometric – galaxies: active – galaxies: individual: NGC 5128 – radio continuum: galaxies McKinley, B. Briggs, F. Gaensler, B. Feain, I. Bernardi, G. Wayth, Randall Johnston-Hollitt, M. Offringa, A. Arcus, Wayne Barnes, D. Bowman, J. Bunton, J. Capallo, R. Corey, B. Deshpande, A. deSouza, L. Emrich, David Goeke, R. Greenhill, L. Hazelton, B. Herne, David Hewitt, J. Kaplan, David Kasper, J. Kincaid, B. Koenig, R. Kratzenberg, E. Lonsdale, C. Lynch, Mervyn McWhirter, S. Mitchell, D. Morales, M. Morgan, E. Oberoi, D. Ord, Stephen Pathikulangara, J. Prabu, T. Remillard, R. Rogers, A. Roshi, D. Salah, J. Sault, R. Udaya Shankar, N. Srivani, K. Stevens, J. Subrahmanyan, R. Tingay, Steven Waterson, Mark Webster, R. Whitney, A. Williams, Andrew Williams, C. Wyithe, J. The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array |
| title | The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array |
| title_full | The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array |
| title_fullStr | The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array |
| title_full_unstemmed | The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array |
| title_short | The giant lobes of Centaurus A observed at 118MHz with the Murchison Widefield Array |
| title_sort | giant lobes of centaurus a observed at 118mhz with the murchison widefield array |
| topic | techniques: interferometric – galaxies: active – galaxies: individual: NGC 5128 – radio continuum: galaxies |
| url | http://hdl.handle.net/20.500.11937/42187 |