Global 21-cm signal extraction from foreground and instrumental effects III: Utilizing drift-scan time dependence and full Stokes measurements

Abstract

When using valid foreground and signal models, the uncertainties on extracted signals in global 21-cm signal experiments depend principally on the overlap between signal and foreground models. In this paper, we investigate two strategies for decreasing this overlap: (i) utilizing time dependence by fitting multiple drift-scan spectra simultaneously and (ii) measuring all four Stokes parameters instead of only the total power, Stokes I. Although measuring polarization requires different instruments than are used in most existing experiments, all existing experiments can utilize drift-scan measurements merely by averaging their data differently. In order to evaluate the increase in constraining power from using these two techniques, we define a method for connecting Root-Mean-Square (RMS) uncertainties to probabilistic confidence levels. Employing simulations, we find that fitting only one total power spectrum leads to RMS uncertainties at the few K level, while fitting multiple time-binned, drift-scan spectra yields uncertainties at the $\lesssim 10$ mK level. This significant improvement only appears if the spectra are modeled with one set of basis vectors, instead of using multiple sets of basis vectors that independently model each spectrum. Assuming that they are simulated accurately, measuring all four Stokes parameters also leads to lower uncertainties. These two strategies can be employed simultaneously and fitting multiple time bins of all four Stokes parameters yields the best precision measurements of the 21-cm signal, approaching the noise level in the data.

arXiv comment16 pages, 6 figures, accepted for publication in ApJ

References in corpus (16)

• 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
• Reionization and Cosmology with 21 cm Fluctuations
• Constraining the unexplored period between reionization and the dark ages with observations of the global 21 cm signal
• Results from EDGES High-Band: I. Constraints on Phenomenological Models for the Global $21$ cm Signal
• Decoding the X-ray Properties of Pre-Reionization Era Sources
• Systematic errors in cosmic microwave background polarization measurements
• Chromatic effects in the 21 cm global signal from the cosmic dawn
• Global 21cm signal experiments: A designer's guide
• Global 21-cm signal extraction from foreground and instrumental effects I: Pattern recognition framework for separation using training sets
• Erasing the variable: Empirical foreground discovery for global 21 cm spectrum experiments
• Global 21-cm Signal Extraction from Foreground and Instrumental Effects II: Efficient and Self-Consistent Technique for Constraining Nonlinear Signal Models
• Modeling the Radio Foreground for detection of CMB spectral distortions from Cosmic Dawn and Epoch of Reionization
• Assessment of the Projection-induced Polarimetry Technique for Constraining the Foreground Spectrum in Global 21 cm Cosmology
• A Translational Polarization Rotator

Cited by in corpus (24)

• A General Bayesian Framework for Foreground Modelling and Chromaticity Correction for Global 21cm Experiments
• Transformative Science from the Lunar Farside: Observations of the Dark Ages and Exoplanetary Systems at Low Radio Frequencies
• Mapper of the IGM spin temperature: instrument overview
• Global 21-cm Signal Extraction from Foreground and Instrumental Effects II: Efficient and Self-Consistent Technique for Constraining Nonlinear Signal Models
• Lunar Orbit Measurement of Cosmic Dawn 21 cm Global Spectrum
• Use of Time Dependent Data in Bayesian Global 21cm Foreground and Signal Modelling
• Lost Horizon: Quantifying the Effect of Local Topography on Global 21-cm Cosmology Data Analysis
• A Bayesian Calibration Framework for EDGES
• Global 21-cm signal extraction from foreground and instrumental effects IV: Accounting for realistic instrument uncertainties and their overlap with foreground and signal models
• Modelling the Galactic Foreground and Beam Chromaticity for Global 21-cm Cosmology
• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- I. Mathematical formalism
• Global 21-cm Cosmology from the Farside of the Moon
• Simulating the Detection of the Global 21 cm Signal with MIST for Different Models of the Soil and Beam Directivity
• A General Bayesian Framework to Account for Foreground Map Errors in Global 21-cm Experiments
• Sky-averaged 21-cm signal extraction using multiple antennas with an SVD framework: the REACH case
• Joint constraints on reionization: a framework for combining the global 21cm signal and the kinetic Sunyaev-Zel'dovich effect
• Simulation-Based Inference of the sky-averaged 21-cm signal from CD-EoR with REACH
• Ensuring Robustness in Training Set Based Global 21-cm Cosmology Analysis
• Sensitivity of the Global 21-cm Signal to Dark Matter-Baryon Scattering
• Constraining a Model of the Radio Sky Below 6 MHz Using the Parker Solar Probe/FIELDS Instrument in Preparation for Upcoming Lunar-based Experiments
• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- II. Model priors and posterior odds
• On the Possibility of Detecting a Global Signal in the Line of the Hyperfine Structure of Hydrogen from the Dark Ages
• On Measuring the 21 cm Global Spectrum of the Cosmic Dawn with an Interferometer Array
• Optimizing Foreground Modelling for Global 21cm Cosmology with GPU-Accelerated Nested Sampling