The young stellar population in NGC 247 Main properties and hierarchical
  clustering
  The aim of this work is to investigate the characteristics of the young
stellar population in the spiral galaxy NGC 247. In particular, we focused our
attention in its hierarchical clustering distributions and the properties of
the smallest groups. We used multiband Hubble Space Telescope (HST) data from
three fields covering more than half of NGC 247 to select the young population.
Then, through the path linkage criterion (PLC), we found compact young star
groups, and estimated their fundamental parameters, such as their stellar
densities, sizes, amount of members and luminosity function (LF) slopes. We
also performed a fractal analysis to determinate the clustering properties of
this population. We build a stellar density map and the corresponding
dendrograms corresponding to the galactic young population to detect large
structures and draw their main characteristics. We detected 339 young star
groups, for which we computed a mean radius of $\sim$ 60 pc and a maximum in
the size distribution between 30 and 70 pc. We also obtained LF slopes with a
bimodal distribution showing peaks at $\sim$ 0.1 and $\sim$ 0.2. We identified
several candidates to HII regions which follow an excellent spatial correlation
with the young groups found by the PLC. We observed that the young population
are hierarchically organized, where the smaller and denser structures are
within larger and less dense ones. We noticed that all these groups presented a
fractal subclustering, following the hierarchical distribution observed in the
corresponding stellar density map. For the large young structures observed in
this map, we obtained a fractal dimension of $\sim$ 1.6-1.8 using the
perimeter-area relation and the cumulative size distribution. These values are
consistent with a scenario of hierarchical star formation.
