Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA
Synchrotron emission pervades the Galactic plane at low radio frequencies, originating from cosmic ray electrons interacting with the Galactic magnetic field. Using a low-frequency radio telescope, the Murchison Widefield Array (MWA), we measure the free-free absorption of this Galactic synchrotron...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
Oxford University Press
2017
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| Online Access: | http://hdl.handle.net/20.500.11937/51676 |
| _version_ | 1848758751729811456 |
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| author | Su, H. Hurley-Walker, Natasha Jackson, Carole McClure-Griffiths, N. Tingay, Steven Hindson, L. Hancock, P. Wayth, Randall Gaensler, B. Staveley-Smith, L. Morgan, J. Johnston-Hollitt, M. Lenc, E. Bell, M. Callingham, J. Dwarkanath, K. For, B. Kapinska, A. McKinley, B. Offringa, A. Procopio, P. Wu, C. Zheng, Q. |
| author_facet | Su, H. Hurley-Walker, Natasha Jackson, Carole McClure-Griffiths, N. Tingay, Steven Hindson, L. Hancock, P. Wayth, Randall Gaensler, B. Staveley-Smith, L. Morgan, J. Johnston-Hollitt, M. Lenc, E. Bell, M. Callingham, J. Dwarkanath, K. For, B. Kapinska, A. McKinley, B. Offringa, A. Procopio, P. Wu, C. Zheng, Q. |
| author_sort | Su, H. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Synchrotron emission pervades the Galactic plane at low radio frequencies, originating from cosmic ray electrons interacting with the Galactic magnetic field. Using a low-frequency radio telescope, the Murchison Widefield Array (MWA), we measure the free-free absorption of this Galactic synchrotron emission by intervening HII regions along the line of sight. These absorption measurements allow us to calculate the Galactic cosmic ray electron emissivity behind and in front of 47 detected HII regions in the region 250° < l < 355°, |b| < 2°.We find that all average emissivities between the HII regions and the Galactic edge along the line of sight (eb) are in the range of 0.39 ~ 1.45 K pc-1 with a mean of 0.77 K pc-1 and a variance of 0.14 K pc-1 at 88 MHz. Our best model, the two-circle model, divides the Galactic disc into three regions using two circles centring on the Galactic Centre. It shows a high emissivity region near the Galactic Centre, a low emissivity region near the Galactic edge, and a medium emissivity region between these two regions, contrary to the trend found by previous studies. |
| first_indexed | 2025-11-14T09:48:58Z |
| format | Journal Article |
| id | curtin-20.500.11937-51676 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:48:58Z |
| publishDate | 2017 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-516762018-04-09T03:24:27Z Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA Su, H. Hurley-Walker, Natasha Jackson, Carole McClure-Griffiths, N. Tingay, Steven Hindson, L. Hancock, P. Wayth, Randall Gaensler, B. Staveley-Smith, L. Morgan, J. Johnston-Hollitt, M. Lenc, E. Bell, M. Callingham, J. Dwarkanath, K. For, B. Kapinska, A. McKinley, B. Offringa, A. Procopio, P. Wu, C. Zheng, Q. Synchrotron emission pervades the Galactic plane at low radio frequencies, originating from cosmic ray electrons interacting with the Galactic magnetic field. Using a low-frequency radio telescope, the Murchison Widefield Array (MWA), we measure the free-free absorption of this Galactic synchrotron emission by intervening HII regions along the line of sight. These absorption measurements allow us to calculate the Galactic cosmic ray electron emissivity behind and in front of 47 detected HII regions in the region 250° < l < 355°, |b| < 2°.We find that all average emissivities between the HII regions and the Galactic edge along the line of sight (eb) are in the range of 0.39 ~ 1.45 K pc-1 with a mean of 0.77 K pc-1 and a variance of 0.14 K pc-1 at 88 MHz. Our best model, the two-circle model, divides the Galactic disc into three regions using two circles centring on the Galactic Centre. It shows a high emissivity region near the Galactic Centre, a low emissivity region near the Galactic edge, and a medium emissivity region between these two regions, contrary to the trend found by previous studies. 2017 Journal Article http://hdl.handle.net/20.500.11937/51676 10.1093/mnras/stw2959 Oxford University Press fulltext |
| spellingShingle | Su, H. Hurley-Walker, Natasha Jackson, Carole McClure-Griffiths, N. Tingay, Steven Hindson, L. Hancock, P. Wayth, Randall Gaensler, B. Staveley-Smith, L. Morgan, J. Johnston-Hollitt, M. Lenc, E. Bell, M. Callingham, J. Dwarkanath, K. For, B. Kapinska, A. McKinley, B. Offringa, A. Procopio, P. Wu, C. Zheng, Q. Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA |
| title | Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA |
| title_full | Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA |
| title_fullStr | Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA |
| title_full_unstemmed | Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA |
| title_short | Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA |
| title_sort | galactic synchrotron emissivity measurements between 250° < l < 355° from the gleam survey with the mwa |
| url | http://hdl.handle.net/20.500.11937/51676 |