A simpler way to read the 21-cm signal from the cosmic dawn

The 21-cm glow from neutral hydrogen during reionization is twisted into non-Gaussian patterns that standard power spectra miss. The authors tested marked statistics—a technique that weights data by custom properties to highlight specific features—on 21-cm simulations and found they capture reionization physics as well as expensive bispectrum analyses but with less computational cost. This approach could tighten constraints on how and when the universe reionized when applied to upcoming radio telescopes.