BERNARDI, GIANNIGIANNIBERNARDIZwart, J. T. L.J. T. L.ZwartPrice, D.D.PriceGreenhill, L. J.L. J.GreenhillMesinger, A.A.MesingerDowell, J.J.DowellEftekhari, T.T.EftekhariEllingson, S. W.S. W.EllingsonKocz, J.J.KoczSchinzel, F.F.Schinzel2020-05-252020-05-2520160035-8711http://hdl.handle.net/20.500.12386/25132The birth of the first luminous sources and the ensuing epoch of reionization are best studied via the redshifted 21-cm emission line, the signature of the first two imprinting the last. In this work, we present a fully Bayesian method, HIBAYES, for extracting the faint, global (sky-averaged) 21-cm signal from the much brighter foreground emission. We show that a simplified (but plausible) Gaussian model of the 21-cm emission from the Cosmic Dawn epoch (15 ≲ z ≲ 30), parametrized by an amplitude A_{H I}, a frequency peak ν _{H I} and a width σ _{H I}, can be extracted even in the presence of a structured foreground frequency spectrum (parametrized as a seventh-order polynomial), provided sufficient signal-to-noise (400 h of observation with a single dipole). We apply our method to an early, 19-min-long observation from the Large aperture Experiment to detect the Dark Ages, constraining the 21-cm signal amplitude and width to be -890 < A_{H I} < 0 mK and σ _{H I} > 6.5 MHz (corresponding to ∆z > 1.9 at redshift z ≃ 20) respectively at the 95-per cent confidence level in the range 13.2 < z < 27.4 (100 > ν > 50 MHz).STAMPAenArticle10.1093/mnras/stw14992-s2.0-84983792816000383481100041https://academic.oup.com/mnras/article/461/3/2847/26086192016MNRAS.461.2847BFIS/05 - ASTRONOMIA E ASTROFISICA