A general Bayesian framework for foreground modelling and chromaticity correction for global 21 cm experiments
نویسندگان
چکیده
The HI 21cm absorption line is masked by bright foregrounds and systematic distortions that arise due to the chromaticity of antenna used make observation coupling spectral inhomogeneity these foregrounds. We demonstrate are sufficient conceal signal when not perfectly achromatic simple corrections assuming a constant spatial distribution foreground power insufficient overcome them. then propose new physics-motivated method modelling experiments in order fit chromatic as part This done generating simulated sky model across observing band dividing into $N$ regions scaling base map distinct uniform index each region. resulting can be convolved with beam give parameterised indices regions. fitting this for varying using Bayesian nested sampling algorithm comparing results evidence allows reliably detected data relatively smooth conical log spiral antenna. also test much more sinuous find will produce reliable detection, but manner easily distinguishable from true detection.
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2021
ISSN: ['0035-8711', '1365-8711', '1365-2966']
DOI: https://doi.org/10.1093/mnras/stab1765