Intervening C i absorption towards the quasar PKS 0237−23: spectrum (black curve) and simultaneous fit to the two transitions (red curve). The green curves correspond to a fit with a spatial coverage factor C_f = 0.85 of the Lyα emission line. In the bottom panel, bluewards of C iλ1560 line (which falls at the top of Lyα emission) C ivλ1550 absorption at z_abs = 1.52580 is present as well as a weak, somewhat broad Lyα absorption. At v_helio = 0 km s^-1, the redshift is z = 1.364695.