Simultaneously constraining the astrophysics of reionisation and the epoch of heating with 21CMMC

Abstract

The cosmic 21 cm signal is set to revolutionise our understanding of the early Universe, allowing us to probe the 3D temperature and ionisation structure of the intergalactic medium (IGM). It will open a window onto the unseen first galaxies, showing us how their UV and X-ray photons drove the cosmic milestones of the epoch of reionisation (EoR) and epoch of heating (EoH). To facilitate parameter inference from the 21 cm signal, we previously developed 21CMMC: a Monte Carlo Markov Chain sampler of 3D EoR simulations. Here we extend 21CMMC to include simultaneous modelling of the EoH, resulting in a complete Bayesian inference framework for the astrophysics dominating the observable epochs of the cosmic 21 cm signal. We demonstrate that second generation interferometers, the Hydrogen Epoch of Reionisation Array (HERA) and Square Kilometre Array (SKA) will be able to constrain ionising and X-ray source properties of the first galaxies with a fractional precision of order $\sim 1$-10 per cent (1$\sigma$). The ionisation history of the Universe can be constrained to within a few percent. Using our extended framework, we quantify the bias in EoR parameter recovery incurred by the common simplification of a saturated spin temperature in the IGM. Depending on the extent of overlap between the EoR and EoH, the recovered astrophysical parameters can be biased by $\sim 3-10\sigma$.

20 pages, 10 figures, 4 tables. Accepted to MNRAS (matches online version). Movies showing the imprint of the astrophysical parameters on the 21cm signal can be found at http://homepage.sns.it/mesinger/21CMMC.html

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Cited by in corpus (9)

• Improved Constraints on the 21 cm EoR Power Spectrum and the X-Ray Heating of the IGM with HERA Phase I Observations
• Mitigating Internal Instrument Coupling for 21 cm Cosmology I: Temporal and Spectral Modeling in Simulations
• Evaluating machine learning techniques for predicting power spectra from reionization simulations
• Evaluating the QSO contribution to the 21-cm signal from the Cosmic Dawn
• Improved supervised learning methods for EoR parameters reconstruction
• Inferring Astrophysics and Dark Matter Properties from 21cm Tomography using Deep Learning
• The bispectrum and 21cm foregrounds during the Epoch of Reionization
• Constraining the Reionization History using Bayesian Normalizing Flows
• Reionization relics in the cross-correlation between the Ly$\alpha$ forest and 21 cm intensity mapping in the post-reionization era