In the early Universe, most of the cold neutral gas that will later form into individual stars and galaxies is practically invisible to us. These neutral gas reservoirs can, however, be illuminated by bright cosmic lightsources such as gamma-ray bursts ...

In the ΛCDM concordance model cold and collision-less dark matter (CDM) accounts for about four fifths of the Universe’s total matter content, while visible baryonic matter makes up the final fifth. The ΛCDM model successfully describes how large ...