Parametrising Epoch of Reionization foregrounds: A deep survey of low-frequency point-source spectra with the MWA
Abstract
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 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 that can be set on source-intrinsic spectral structure. The sensitivity and power-spectrum of the spectra are analysed, and it is found that the spectra of residuals are dominated by PSF sidelobes from nearby undeconvolved sources. We release a catalogue describing the spectral parameters for each measured source.
Keywords
Cite
@article{arxiv.1602.02247,
title = {Parametrising Epoch of Reionization foregrounds: A deep survey of low-frequency point-source spectra with the MWA},
author = {A. R. Offringa and C. M. Trott and N. Hurley-Walker and M. Johnston-Hollitt and B. McKinley and N. Barry and A. P. Beardsley and J. D. Bowman and F. Briggs and P. Carroll and J. S. Dillon and A. Ewall-Wice and L. Feng and B. M. Gaensler and L. J. Greenhill and B. J. Hazelton and J. N. Hewitt and D. C. Jacobs and H. -S. Kim and P. Kittiwisit and E. Lenc and J. Line and A. Loeb and D. A. Mitchell and M. F. Morales and A. R. Neben and S. Paul and B. Pindor and J. C. Pober and P. Procopio and J. Riding and S. K. Sethi and N. U. Shankar and R. Subrahmanyan and I. S. Sullivan and M. Tegmark and N. Thyagarajan and S. J. Tingay and R. B. Wayth and R. L. Webster and J. S. B. Wyithe},
journal= {arXiv preprint arXiv:1602.02247},
year = {2016}
}
Comments
Accepted for publication in MNRAS. 15 pages, 16 figures. Catalogue of sources externally available as CSV file