Are Nuclear Star Clusters the Precursors of Massive Black Holes?
Figure 1
The ratio assumed for the stellar population against the mass of the putative black hole for each of the nine nuclear clusters. Models falling onto the right solid vertical line have the same velocity dispersion as given in Table 1 for each cluster (dashed lines are upper and lower uncertainties). We also draw a vertical, full line (left) for the minimum mass-to-light ratio compatible with the observed spectrum of the stellar population in the cluster. The horizontal solid lines indicate the black hole masses referring to the two different values quoted previously. For the minimum we find a firm upper limit to the black hole mass (upper line) and for the best-fit stellar populations we get (lower line).
