L_acc  values for the different accretion tracers considered (see Tables 5 and 6) plotted as a function of L_∗: from top to bottom Brγ, Paβ, Hα, [O i] λ6300, Ca ii λ8542. Red circles and blue squares refer to detections of Cha I and Cha II objects, respectively. Upper limits are indicated by downward triangles. The solid and dashed lines show the locus where L_acc = L_∗  and L_acc = 0.1 L_∗, respectively. The error bars reflect only the assumed uncertainty of 0.5 mag for the 2MASS K band magnitude used as reference for the absolute flux calibration of the spectra (see Sect. 4).