A Bayesian Calibration Framework for EDGES

Abstract

We develop a Bayesian model that jointly constrains receiver calibration, foregrounds and cosmic 21cm signal for the EDGES global 21\,cm experiment. This model simultaneously describes calibration data taken in the lab along with sky-data taken with the EDGES low-band antenna. We apply our model to the same data (both sky and calibration) used to report evidence for the first star formation in 2018. We find that receiver calibration does not contribute a significant uncertainty to the inferred cosmic signal (<1%), though our joint model is able to more robustly estimate the cosmic signal for foreground models that are otherwise too inflexible to describe the sky data. We identify the presence of a significant systematic in the calibration data, which is largely avoided in our analysis, but must be examined more closely in future work. Our likelihood provides a foundation for future analyses in which other instrumental systematics, such as beam corrections and reflection parameters, may be added in a modular manner.

arXiv comment18 pages + 3 for appendices. 13 figures. Accepted to MNRAS

References in corpus (35)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Array Programming with NumPy
• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• An absorption profile centred at 78 megahertz in the sky-averaged spectrum
• 21-cm cosmology
• PolyChord: nested sampling for cosmology
• PolyChord: next-generation nested sampling
• Concerns about Modelling of the EDGES Data
• The Epoch of Reionization Window: II. Statistical Methods for Foreground Wedge Reduction
• Testing for calibration systematics in the EDGES low-band data using Bayesian model selection
• BIGHORNS - Broadband Instrument for Global HydrOgen ReioNisation Signal
• Realistic Simulations of the Galactic Polarized Foreground: Consequences for 21-cm Reionization Detection Experiments
• The redshifted 21-cm signal in the EDGES low-band spectrum
• Bayesian constraints on the global 21-cm signal from the Cosmic Dawn
• Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization
• Results from EDGES High-Band: I. Constraints on Phenomenological Models for the Global $21$ cm Signal
• Calibration of the EDGES High-Band Receiver to Observe the Global 21-cm Signature from the Epoch of Reionization
• Absolute calibration of a wideband antenna and spectrometer for sky noise spectral index measurements
• A General Bayesian Framework for Foreground Modelling and Chromaticity Correction for Global 21cm Experiments
• Results from EDGES High-Band: III. New Constraints on Parameters of the Early Universe
• Spectral Index of the Diffuse Radio Background Between 50 and 100 MHz
• SARAS 3 CD/EoR Radiometer: Design and Performance of the Receiver
• GLOBALEMU: A novel and robust approach for emulating the sky-averaged 21-cm signal from the cosmic dawn and epoch of reionisation
• Results from EDGES High-Band: II. Constraints on Parameters of Early Galaxies
• Formulating and critically examining the assumptions of global 21-cm signal analyses: How to avoid the false troughs that can appear in single spectrum fits
• Validation of EDGES Low-Band Antenna Beam Model
• The 21-cm Line as a Probe of Reionization
• Informing antenna design for sky-averaged 21-cm experiments using a simulated Bayesian data analysis pipeline
• Global 21-cm signal extraction from foreground and instrumental effects III: Utilizing drift-scan time dependence and full Stokes measurements
• Bayesian noise wave calibration for 21-cm global experiments
• Global 21-cm signal extraction from foreground and instrumental effects IV: Accounting for realistic instrument uncertainties and their overlap with foreground and signal models
• The All-Sky SignAl Short-Spacing INterferometer (ASSASSIN) I: Global sky measurements with the Engineering Development Array-2
• SARAS CD/EoR Radiometer: Design and performance of the Digital Correlation Spectrometer

Cited by in corpus (17)

• 21cmEMU: an emulator of 21cmFAST summary observables
• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- I. Mathematical formalism
• A General Bayesian Framework to Account for Foreground Map Errors in Global 21-cm Experiments
• RHINO: A large horn antenna for detecting the 21cm global signal
• The EDGES measurement disfavors an excess radio background during the cosmic dawn
• Relic neutrino decay solution to the excess radio background
• Rapid and Late Cosmic Reionization Driven by Massive Galaxies: a Joint Analysis of Constraints from 21-cm, Lyman Line & CMB Data Sets
• A Differentiable, End-to-End Forward Model for 21 cm Cosmology: Estimating the Foreground, Instrument, and Signal Joint Posterior
• Accounting for Noise and Singularities in Bayesian Calibration Methods for Global 21-cm Cosmology Experiments
• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- II. Model priors and posterior odds
• Constraining a Model of the Radio Sky Below 6 MHz Using the Parker Solar Probe/FIELDS Instrument in Preparation for Upcoming Lunar-based Experiments
• Forecast measurement of the 21 cm global spectrum from Lunar orbit with the Vari-Zeroth-Order Polynomial (VZOP) method
• Radiometer Calibration using Machine Learning
• EDGES of the dark forest: A new absorption window into the composite dark matter and large scale structure
• Capturing System Drift with Time Series Calibration for Global 21-cm Cosmology Experiments
• The magnitude of the dark ages 21-cm signal in the context of existing early and late time constraints on $\Lambda$CDM
• Optimizing Foreground Modelling for Global 21cm Cosmology with GPU-Accelerated Nested Sampling