Evolution of disk gas at different redshifts. For each snapshot at a given redshift z, gas particles that are cold and in the disk are tracked forward until an outcome is identified: the particle is heated within the disk, the particle is launched in an outflow but is still cold, the particle is launched in an outflow and is heated above T₀, or the particle is converted into stars. If none of the previous outcomes is found earlier than z = 0.3, it means that the particle remains cold in the disk. Left: total mass of the gas in each outcome. Right: fraction of the gas mass in each outcome, with respect to the initial cold disk gas at the redshift z at which the forward tracking is started.