considered to be the modern-day counterpart of proto-GCs and this study therefore implies that heating does not play an important role in the environment where the accretion process is believed to take place.

We can also estimate the cooling time scale for stellar ejecta from Eq. \[eq:cooling\_tau\_eda1\], to justify that the expelled gas cools fast to low temperatures. As a lower limit for the density of stellar ejecta we assume $n = 10^2 \mathrm{cm}^{-3}$ and $T = 10^4$ K [@smith07 see also B13]. Combined with an appropriate cooling rate of $\Lambda \approx 10^{-25} \mathrm{erg\,cm^3 / s}$ [@richings14] this results in a cooling time scale of roughly 6500 years. We consider this an upper limit, because assuming a higher density for the stellar ejecta would result in an even shorter cooling time scale. Consequently, the cooling time scale is at least three to four orders of magnitude smaller than the $10^{7}$ years time scale on which the early disc accretion scenario is expected to take place. Our assumption that the ISM has cooled sufficiently and can be approximated with a temperature of 25 K is therefore justified.

To estimate the density of the ISM in the early disc accretion scenario we 