Mapping Cosmic Dawn and Reionization: Challenges and Synergies

TL;DR

This paper discusses the challenges and opportunities in mapping the Cosmic Dawn and Epoch of Reionization using multi-wavelength intensity mapping, emphasizing the importance of coordinated surveys and models for advancing understanding.

Contribution

It highlights the potential of multi-wavelength intensity mapping and the need for coordinated survey strategies to improve insights into the Cosmic Dawn and reionization.

Findings

Upcoming observations will likely detect inhomogeneous reionization.

Multi-wavelength data can provide synergistic insights.

Joint analysis and modeling are crucial for progress.

Abstract

Cosmic dawn and the Epoch of Reionization (EoR) are among the least explored observational eras in cosmology: a time at which the first galaxies and supermassive black holes formed and reionized the cold, neutral Universe of the post-recombination era. With current instruments, only a handful of the brightest galaxies and quasars from that time are detectable as individual objects, due to their extreme distances. Fortunately, a multitude of multi-wavelength intensity mapping measurements, ranging from the redshifted 21 cm background in the radio to the unresolved X-ray background, contain a plethora of synergistic information about this elusive era. The coming decade will likely see direct detections of inhomogenous reionization with CMB and 21 cm observations, and a slew of other probes covering overlapping areas and complementary physical processes will provide crucial additional information and cross-validation. To maximize scientific discovery and return on investment, coordinated survey planning and joint data analysis should be a high priority, closely coupled to computational models and theoretical predictions.