Title:	Galactic synchrotron distribution derived from 152 H II region absorption features in the full GLEAM survey
Authors:	Su, H. Dwarakanath, K.S. +21 authors
Keywords:	cosmic rays H II regions Galaxy structure radio continuum general
Issue Date:	21-Sep-2018
Publisher:	Oxford University Press for The Royal Astronomical Society
Citation:	Monthly Notices of the Royal Astronomical Society, 2018, Vol. 479, p 4041-4055
Abstract:	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.
Description:	Open Access
URI:	http://hdl.handle.net/2289/6993
ISSN:	0035-8711 1365-2966 - (online)
Alternative Location:	https://arxiv.org/abs/1806.10611 https://doi.org/10.1093/mnras/sty1732
Copyright:	2018 The authors
Appears in Collections:	Research Papers (A&A)

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