Brightness temperature simulation
Evolution of a coeval cube, simulated in the redshift range z= 5 - 25. The dimensions of the box are 200x200 Mpc and the resolution is 100x100 pixels. The brightness temperature is the characteristic temperature associated with the 21 cm signal, a spectral line arising from the spin-flip transition of neutral hydrogen. It is expressed in terms of the deviation from the 21 cm signal from the cosmic microwave background. Since hydrogen is abundant and traces the neutral IGM, this 21 cm signal serves as a key probe for studying structure formation and reionization.