Galactic synchrotron emissivity measurements between 250 degrees < l < 355 degrees from the GLEAM survey with the MWA
H Su, N Hurley-Walker, CA Jackson, NM McClure-Griffiths, SJ Tingay, L Hindson, P Hancock, RB Wayth, BM Gaensler, L Staveley-Smith, J Morgan, M Johnston-Hollitt, E Lenc, ME Bell, JR Callingham, KS Dwarkanath, B-Q For, AD Kapinska, B McKinley, AR Offringa Show all
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | OXFORD UNIV PRESS | Published : 2017
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 (εb) are in the range of 0.39 ~ 1.45 K pc-1 with..View full abstract
Awarded by NSFC
Awarded by Science and Technology Facilities Council
We thank the referee for a number of useful suggestions which improved this paper. This work makes use of the Murchison Radioastronomy Observatory, operated by CSIRO. We acknowledge the Wajarri Yamatji people as the traditional owners of the Observatory site. Support for the operation of the MWA is provided by the Australian Government (NCRIS), under a contract to Curtin University administered by Astronomy Australia Limited. We acknowledge the Pawsey Supercomputing Centre which is supported by the Western Australian and Australian Governments. HS thanks the support from the NSFC (11473038, 11273025). CAJ thanks the Department of Science, Office of Premier & Cabinet, WA for their support through the Western Australian Fellowship Program.