Bayesian evidence-driven diagnosis of instrumental systematics for sky-averaged 21-cm cosmology experiments

Abstract

We demonstrate the effectiveness of a Bayesian evidence-based analysis for diagnosing and disentangling the sky-averaged 21-cm signal from instrumental systematic effects. As a case study, we consider a simulated REACH pipeline with an injected systematic. We demonstrate that very poor performance or erroneous signal recovery is achieved if the systematic remains unmodelled. These effects include sky-averaged 21-cm posterior estimates resembling a very deep or wide signal. However, when including parameterised models of the systematic, the signal recovery is dramatically improved in performance. Most importantly, a Bayesian evidence-based model comparison is capable of determining whether or not such a systematic model is needed as the true underlying generative model of an experimental dataset is in principle unknown. We, therefore, advocate a pipeline capable of testing a variety of potential systematic errors with the Bayesian evidence acting as the mechanism for detecting their presence.

accepted to PASA

References in corpus (9)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• PolyChord: nested sampling for cosmology
• Evolution of the 21 cm signal throughout cosmic history
• Signature of Excess Radio Background in the 21-cm Global Signal and Power Spectrum
• Testing for calibration systematics in the EDGES low-band data using Bayesian model selection
• Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization
• Improved Measurement of the Spectral Index of the Diffuse Radio Background Between 90 and 190 MHz
• Radio background and IGM heating due to Pop III supernovae explosions
• A Comprehensive Bayesian re-analysis of the SARAS2 data from the Epoch of Reionization

Cited by in corpus (8)

• The REACH radiometer for detecting the 21-cm hydrogen signal from redshift 7.5 to 28
• A General Bayesian Framework to Account for Foreground Map Errors in Global 21-cm Experiments
• Bayesian evidence-driven likelihood selection for sky-averaged 21-cm signal extraction
• Impact of extragalactic point sources on the low-frequency sky spectrum and cosmic dawn global 21-cm measurements
• Accounting for Noise and Singularities in Bayesian Calibration Methods for Global 21-cm Cosmology Experiments
• A Bayesian Method to Mitigate the Effects of Unmodelled Time-Varying Systematics for 21-cm Cosmology Experiments
• Constraining a Model of the Radio Sky Below 6 MHz Using the Parker Solar Probe/FIELDS Instrument in Preparation for Upcoming Lunar-based Experiments
• Optimizing Foreground Modelling for Global 21cm Cosmology with GPU-Accelerated Nested Sampling