Values of the M/L_V ratio as a function of L_V for three different times 5, 10, 13 Gyr. The case of the MKDP IMF is not constant since the MKDP IMF is a function of initial mass. The plotted curves assume all remnants are kept; if only a fraction are kept, the M/L_V values would become smaller accordingly. There are two horizontal axes, the one on the top of the plots shows corresponding values of the absolute magnitude in the rest-frame V band. The observed values of M/L_V for UCDs are in the interval from approximately five to ten, with few values spanning up to 15 (Mieske et al. 2002), which are shown by the grey band. The points plotted on the curves mark luminosities and M/L_V values for UCDs starting with initial mass of 10⁹,10⁸, and 10⁷ M_⊙. Left panel: [Fe/H] = −2. Right panel: [Fe/H] = 0.