Hierarchy of clumps fragments : a den for the formation of local star-clusters using a graph theory-based approach

The spatial distribution of YSOs might give some clues on the fragmentation process of molecular clouds. Indeed, the small significant stellar structures (NESTs) discovered in Taurus (Joncour+18) are interpreted as pristine imprints of star formation process and may be a consequence of the fragmentation of gaseous substructures. This work aims to investigate at which spatial scale gas clumps are fragmenting to form NESTs. We design a graph theory-based approach to characterise the properties of fragmentation and apply it to Herschel observations of NGC2264.

Using the getsf procedure (Men’shchikov+21), we extracted clumps catalogs at various scales in both observations and simulations. The observational data sets are taken from the Herschel’s five bands density maps of NGC2264, covering scales from ~6kAU to ~26kAU. From those catalogs we build a directed graph in which the nodes are associated to the individual clumps and the links between them define an inclusive relation between ravelled clumps.

Spatial distribution of structures in NGC2264 revealed that hierarchical nested fragmentation is primary observed in the high density central part of NGC2264 whereas monolothic collapse occurs in the sparser regions. Star formation may result from hierarchical fractal collapse of massive dense cores.