Data from HST Survey of the Orion Nebula Cluster ACS/Visible Bands. IV. Star formation in the ONC

We have performed a comprehensive study of the Orion Nebula Cluster (ONC) combining the photometric data obtained by the two \textit{HST} Treasury programs that targeted this region.
To consistently analyze the rich dataset obtained in a wide variety of filters, we adopted a Bayesian approach to fit the Spectral Energy Distribution of the sources, deriving mass, age, extinction, distance, and accretion for each source in the region. The resulting age distribution of the bona-fide cluster members strongly supports the idea that star formation in the ONC is best described by a major episode of star formation that happened $\sim 1$ Myr ago.
Our derived empirical IMF for this cluster, characterized as a broken power-law, appears mostly compatible with a Chabrier system IMFs for \Mstar $\leq 0.3$ \Msun, with a possible lack of low-mass/brown dwarf objects at the lowest masses.
Both the accretion luminosity (\Lacc) and mass accretion rates (\dMacc) are also best described by broken power-law relations.
This suggests that for the majority of young circumstellar disks in this cluster the excess emission may be dominated by X-ray-driven photoevaporation by the centrao star rather than external photoevaporation. If this is the case, the slopes of the power-law relations may be largely determined by the initial conditions set at the onset of the star formation process, which may be quite similar between regions that eventually form clusters of different sizes.