Journal article

Parametrizing Epoch of Reionization foregrounds: a deep survey of low-frequency point-source spectra with the Murchison Widefield Array

AR Offringa, CM Trott, N Hurley-Walker, M Johnston-Hollitt, B McKinley, N Barry, AP Beardsley, JD Bowman, F Briggs, P Carroll, JS Dillon, A Ewall-Wice, L Feng, BM Gaensler, LJ Greenhill, BJ Hazelton, JN Hewitt, DC Jacobs, H-S Kim, P Kittiwisit Show all



Experiments that pursue detection of signals from the Epoch of Reionization (EoR) are relying on spectral smoothness of source spectra at low frequencies. This article empirically explores the effect of foreground spectra on EoR experiments by measuring high-resolution full-polarization spectra for the 586 brightest unresolved sources in one of the Murchison Widefield Array (MWA) EoR fields using 45 h of observation. A novel peeling scheme is used to subtract 2500 sources from the visibilities with ionospheric and beam corrections, resulting in the deepest, confusion-limited MWA image so far. The resulting spectra are found to be affected by instrumental effects, which limit the constraints ..

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Awarded by European Research Council under ERC

Awarded by Australian Research Council

Awarded by Centre for All-sky Astrophysics (an Australian Research Council Centre of Excellence)

Awarded by Division Of Astronomical Sciences

Funding Acknowledgements

AO acknowledges financial support from the European Research Council under ERC Advanced Grant LOFARCORE - 339743. MJH acknowledges the support of the Marsden Fund. This research was supported under Australian Research Council's Discovery Early Career Researcher funding scheme (project number DE140100316) and the Centre for All-sky Astrophysics (an Australian Research Council Centre of Excellence funded by grant CE110001020).r This scientific work makes use of the NCI National Facility in Canberra, Australia, which is supported by the Australian Commonwealth Government.r This scientific work makes use of the Murchison Radio astronomy 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 Department of Industry and Science and Department of Education (National Collaborative Research Infrastructure Strategy: NCRIS), under a contract to Curtin University administered by Astronomy Australia Limited. We acknowledge the iVEC Petabyte Data Store and the Initiative in Innovative Computing and the CUDA Center for Excellence sponsored by NVIDIA at Harvard University.