A physical model for [CII] line emission from galaxies

Understand

A tight relation between the [CII]158$\mu$m line luminosity and star formation rate is measured in local galaxies.

• At high redshift ($z>5$), though, a much larger scatter is observed, with a considerable (15-20\%) fraction of the outliers being [CII]-deficient.
• Moreover, the [CII] surface brightness ($\Sigma_{\rm CII}$) of these sources is systematically lower than expected from the local relation.
• To clarify the origin of such [CII]-deficiency we have developed an analytical model that fits local [CII] data, and has been validated against radiative transfer simulations performed with CLOUDY.