HID of the 2010–2011 outburst of GX 339-4. The position of the observations reported in Table 1 are indicated with blue and black colors and are labeled on the HID with their MJD. The black (resp. blue) MJD correspond to observations whose range of the ionization parameter consistent with Fe XXV and Fe XXVI ions is in an unstable (resp. stable) part of the photoionization stability curves. We have distributed the MJD observations in terms of modeled SED and associated stability curves in Fig. 2.