SEDs of 8-Myr-old UCDs at different redshifts. For this purpose, we arbitrarily chose the SED of an 8-Myr-old stellar population with metallicity [Fe/H] = −2 and corrected the spectrum for the wavelength shift and luminosity fainting with luminosity distance for redshifts 3, 6, and 9. Left panel: SEDs of the MKDP IMF. Right panel: SEDs of the CAN IMF. The photometric filters, here approximated by rectangular profiles as shaded vertical regions, are shown. The J, K, and N filters are used in the colour analysis of the data.