An Improved Statistical Point-source Foreground Model for the Epoch of Reionization
MetadataShow full item record
© 2017. The American Astronomical Society. All rights reserved.. We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio sky, we enhance the realism of two model components compared with existing models: the source count distributions as a function of flux density and spatial position (source clustering), extending current formalisms for the foreground covariance of 2D power-spectral modes in 21 cm EoR experiments. The former we generalize to an arbitrarily broken power law, and the latter to an arbitrary isotropically correlated field. This paper presents expressions for the modified covariance under these extensions, and shows that for a more realistic source spatial distribution, extra covariance arises in the EoR window that was previously unaccounted for. Failure to include this contribution can yield bias in the final power-spectrum and under-estimate uncertainties, potentially leading to a false detection of signal. The extent of this effect is uncertain, owing to ignorance of physical model parameters, but we show that it is dependent on the relative abundance of faint sources, to the effect that our extension will become more important for future deep surveys. Finally, we show that under some parameter choices, ignoring source clustering can lead to false detections on large scales, due to both the induced bias and an artificial reduction in the estimated measurement uncertainty.
Showing items related by title, author, creator and subject.
Gupta, Sunil Kumar (2011)The growing number of information sources has given rise to joint analysis. While the research community has mainly focused on analyzing data from a single source, there has been relatively few attempts on jointly analyzing ...
Thermal History and Deep Overpressure Modelling in the Northern Carnarvon Basin, North West Shelf, AustraliaHe, Sheng (2002)The Northern Carnarvon Basin is the richest petroleum province in Australia. About 50 gas/condensate and oil fields, associated mainly with Jurassic source rocks, have been discovered in the sub-basins and on the Rankin ...
A High-Resolution Foreground Model for the MWA EoR1 Field: Model and Implications for EoR Power Spectrum AnalysisProcopio, P.; Wayth, R.; Line, J.; Trott, Cathryn; Intema, H.; Mitchell, D.; Pindor, B.; Riding, J.; Tingay, S.; Bell, M.; Callingham, J.; Dwarakanath, K.; For, B.; Gaensler, B.; Hancock, P.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kapinska, A.; Lenc, E.; McKinley, B.; Morgan, J.; Offringa, A.; Staveley-Smith, L.; Wu, C.; Zheng, Q. (2017)The current generation of experiments aiming to detect the neutral hydrogen signal from the Epoch of Reionisation (EoR) is likely to be limited by systematic effects associated with removing foreground sources from target ...