Cores and filaments in MHD simulations of massive protoclusters

Collisions between giant molecular clouds (GMCs) have been proposed as a mechanism to compress gas to trigger the birth of massive star clusters and associations and thus be potentially relevant to the formation of most stars in galaxies. The spatial distributions of dense gas cores within protoclusters generated by such collisions may encode important diagnostic information about the process and the environmental properties of the parent clouds. To investigate this, we carried out 3D numerical simulations of magnetized turbulent GMCs. Non-colliding cases were also considered. The projected 2D mass surface density structures of the clouds, including cases after applying simulated ALMA observations, were analyzed. In particular, dense cores were identified with the dendrogram method and the Minimum Spanning Tree (MST) of the cores computed. We compared the results from clouds with different initial magnetic (B-) field strengths, ranging from 10 to 50 micro G. The number and mass fraction of dense cores are suppressed in the more strongly magnetized and non-colliding cases. We consider various MST statistics, including the Q parameter, and how these evolve during the simulations and their potential ability to diagnose magnetic and collisional conditions. We also examine mass segregation, including detailed properties of the most massive cores, which relates to the question of whether or not massive stars tend to form in more central locations in protoclusters. Finally, we study the properties of the filaments within and around the protoclusters, including their widths, mass per unit lengths, energy balance and magnetic field strengths and orientations.