MSX Color–color diagram. All MSX sources in the CMZ, detected in all four MSX bands, are plotted with black dots. The black boxes mark all MSX sources with an ISOGAL counterpart within 8″ (177 sources). 656 MSX sources with F_E/F_D  ≥  2 without an ISOGAL counterpart within 8″ are shown as gray circles. The MSX sources, marked with boxes and circles, have flux quality flags  ≥ 1 in the A and C bands and  ≥ 2 in the D and E bands.