Title:	Galactic synchrotron emissivity measurements between 250° < l < 355° from the GLEAM survey with the MWA
Authors:	Su, H Hurley-Walker, N Dwarakanath, K S Jackson, C A McClure-Griffiths, N M Tingay, S J Hindson, L Hancock, P Wayth, R B Gaensler, B M Staveley-Smith, L Morgan , J Johnston-Hollitt , M Lenc, E Bell, M E Callingham, J R For, B-Q Kapińska , A D McKinley, B Offringa, A R Procopio, P Wu, C Zheng, Q
Keywords:	Errata Erratum Cosmic rays
Issue Date:	Mar-2017
Publisher:	Oxford University Press for the Royal Astronomical Society
Citation:	Monthly Notices of the Royal Astronomical Society, 2017, Vol. 465, p3163-3174
Abstract:	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 H II 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 H II regions in the region 250° < l < 355°, |b| < 2°. We find that all average emissivities between the H II regions and the Galactic edge along the line of sight (εb) 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.
Description:	Open Access
URI:	http://hdl.handle.net/2289/6720
ISSN:	0035-8711 1365-2966 - (online)
Alternative Location:	http://adsabs.harvard.edu/abs/2017MNRAS.465.3163S http://arxiv.org/abs/1611.05446 http://dx.doi.org/10.1093/mnras/stw2959
Copyright:	2017 The authors & the Royal Astronomical Society
Appears in Collections:	Research Papers (A&A)

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