Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey

We derive the synchrotron distribution in the Milky Way disc from H II region absorption observations over -40° < l < 40° at six frequencies of 76.2, 83.8, 91.5, 99.2, 106.9, and 114.6 MHz with the GaLactic and Extragalactic All-sky Murchison widefield array survey (GLEAM). We develop...

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Main Authors: Su, H., Macquart, Jean-Pierre, Hurley-Walker, Natasha, McClure-Griffiths, N., Jackson, Carole, Tingay, Steven, Tian, W., Gaensler, B., McKinley, B., Kapínska, A., Hindson, L., Hancock, Paul, Wayth, Randall, Staveley-Smith, L., Morgan, John, Johnston-Hollitt, M., Lenc, E., Bell, M., Callingham, J., Dwarkanath, K., For, B., Offringa, A., Procopio, P., Wu, C., Zheng, Q.
Format: Journal Article
Published: Oxford University Press 2018
Online Access:http://hdl.handle.net/20.500.11937/73228
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author Su, H.
Macquart, Jean-Pierre
Hurley-Walker, Natasha
McClure-Griffiths, N.
Jackson, Carole
Tingay, Steven
Tian, W.
Gaensler, B.
McKinley, B.
Kapínska, A.
Hindson, L.
Hancock, Paul
Wayth, Randall
Staveley-Smith, L.
Morgan, John
Johnston-Hollitt, M.
Lenc, E.
Bell, M.
Callingham, J.
Dwarkanath, K.
For, B.
Offringa, A.
Procopio, P.
Wu, C.
Zheng, Q.
author_facet Su, H.
Macquart, Jean-Pierre
Hurley-Walker, Natasha
McClure-Griffiths, N.
Jackson, Carole
Tingay, Steven
Tian, W.
Gaensler, B.
McKinley, B.
Kapínska, A.
Hindson, L.
Hancock, Paul
Wayth, Randall
Staveley-Smith, L.
Morgan, John
Johnston-Hollitt, M.
Lenc, E.
Bell, M.
Callingham, J.
Dwarkanath, K.
For, B.
Offringa, A.
Procopio, P.
Wu, C.
Zheng, Q.
author_sort Su, H.
building Curtin Institutional Repository
collection Online Access
description We derive the synchrotron distribution in the Milky Way disc from H II region absorption observations over -40° < l < 40° at six frequencies of 76.2, 83.8, 91.5, 99.2, 106.9, and 114.6 MHz with the GaLactic and Extragalactic All-sky Murchison widefield array survey (GLEAM). We develop a new method of emissivity calculation by taking advantage of the Haslam et al. (1981) map and known spectral indices, which enable us to simultaneously derive the emissivity and the optical depth of H II regions at each frequency. We show our derived synchrotron emissivities based on 152 absorption features of H II regions using both the method previously adopted in the literature and our improved method. We derive the synchrotron emissivity from H II regions to the Galactic edge along the line of sight and, for the first time, derive the emissivity from H II regions to the Sun. These results provide direct information on the distribution of the Galactic magnetic field and cosmic ray electrons for future modelling.
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institution Curtin University Malaysia
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last_indexed 2025-11-14T10:55:51Z
publishDate 2018
publisher Oxford University Press
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spelling curtin-20.500.11937-732282019-02-14T06:52:30Z Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey Su, H. Macquart, Jean-Pierre Hurley-Walker, Natasha McClure-Griffiths, N. Jackson, Carole Tingay, Steven Tian, W. Gaensler, B. McKinley, B. Kapínska, A. Hindson, L. Hancock, Paul Wayth, Randall Staveley-Smith, L. Morgan, John Johnston-Hollitt, M. Lenc, E. Bell, M. Callingham, J. Dwarkanath, K. For, B. Offringa, A. Procopio, P. Wu, C. Zheng, Q. We derive the synchrotron distribution in the Milky Way disc from H II region absorption observations over -40° < l < 40° at six frequencies of 76.2, 83.8, 91.5, 99.2, 106.9, and 114.6 MHz with the GaLactic and Extragalactic All-sky Murchison widefield array survey (GLEAM). We develop a new method of emissivity calculation by taking advantage of the Haslam et al. (1981) map and known spectral indices, which enable us to simultaneously derive the emissivity and the optical depth of H II regions at each frequency. We show our derived synchrotron emissivities based on 152 absorption features of H II regions using both the method previously adopted in the literature and our improved method. We derive the synchrotron emissivity from H II regions to the Galactic edge along the line of sight and, for the first time, derive the emissivity from H II regions to the Sun. These results provide direct information on the distribution of the Galactic magnetic field and cosmic ray electrons for future modelling. 2018 Journal Article http://hdl.handle.net/20.500.11937/73228 10.1093/mnras/sty1732 Oxford University Press fulltext
spellingShingle Su, H.
Macquart, Jean-Pierre
Hurley-Walker, Natasha
McClure-Griffiths, N.
Jackson, Carole
Tingay, Steven
Tian, W.
Gaensler, B.
McKinley, B.
Kapínska, A.
Hindson, L.
Hancock, Paul
Wayth, Randall
Staveley-Smith, L.
Morgan, John
Johnston-Hollitt, M.
Lenc, E.
Bell, M.
Callingham, J.
Dwarkanath, K.
For, B.
Offringa, A.
Procopio, P.
Wu, C.
Zheng, Q.
Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey
title Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey
title_full Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey
title_fullStr Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey
title_full_unstemmed Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey
title_short Galactic synchrotron distribution derived from 152 HII region absorption features in the full GLEAM survey
title_sort galactic synchrotron distribution derived from 152 hii region absorption features in the full gleam survey
url http://hdl.handle.net/20.500.11937/73228