A joint survey strategy helps 21 cm intensity mapping become a powerful cosmological probe

摘要

Hydrogen atoms can radiate photons of 21 cm wavelength,which can be used to probe the entire evolution history of the universe after the recombination epoch.A highly efficient way of observing the large scale hydrogen distribution is to make“intensity mapping”surveys,in which the 21 cm intensity of volume pixels(voxels)containing many galaxies is mapped,without resolving individual galaxies[1].