Insights on Dark Matter from Hydrogen during Cosmic Dawn

Understand

The origin and composition of the cosmological dark matter remain a mystery.

• However, upcoming 21-cm measurements during cosmic dawn, the period of the first stellar formation, can provide new clues on the nature of dark matter.
• During this era, the baryon-dark matter fluid is the slowest it will ever be, making it ideal to search for dark matter elastically scattering with baryons through massless mediators, such as the photon.
• Here we explore whether dark-matter particles with an electric "minicharge" can significantly alter the baryonic temperature and, thus, affect 21-cm observations.