Kavli Affiliate: George Efstathiou
| First 5 Authors: , , , ,
| Summary:
Several ongoing and upcoming radio telescopes aim to detect either the global
21 cm signal or the 21 cm power spectrum. The extragalactic radio background,
as detected by ARCADE-2 and LWA-1, suggests a strong radio background from
cosmic dawn, which can significantly alter the cosmological 21 cm signal,
enhancing both the global signal amplitude and the 21 cm power spectrum. In
this paper, we employ an artificial neural network (ANN) to check if there is a
radio excess over the cosmic microwave background in mock data, and if present,
we classify its type into one of two categories, a background from
high-redshift radio galaxies or a uniform exotic background from the early
Universe. Based on clean data (without observational noise), the ANN can
predict the background radiation type with $96%$ accuracy for the power
spectrum and $90%$ for the global signal. Although observational noise reduces
the accuracy, the results remain quite useful. We also apply ANNs to map the
relation between the 21 cm power spectrum and the global signal. By
reconstructing the global signal using the 21 cm power spectrum, an ANN can
estimate the global signal range consistent with an observed power spectrum
from SKA-like experiments. Conversely, we show that an ANN can reconstruct the
21 cm power spectrum over a wide range of redshifts and wavenumbers given the
global signal over the same redshifts. Such trained networks can potentially
serve as a valuable tool for cross-confirmation of the 21 cm signal.
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