Large-scale numerical simulations of star formation put to the test: Comparing synthetic images and actual observations for statistical samples of protostars

Abstract

(abridged) Context: Both observations and simulations of embedded protostars have progressed rapidly in recent years. Bringing them together is an important step in advancing our knowledge about the earliest phases of star formation. Aims: To compare synthetic continuum images and SEDs, calculated from large-scale numerical simulations, to observational studies, thereby aiding in both the interpretation of the observations and in testing the fidelity of the simulations. Methods: The radiative transfer code RADMC-3D is used to create synthetic continuum images and SEDs of protostellar systems in a large numerical simulation of a molecular cloud. More than 13000 unique radiative transfer models are produced of a variety of different protostellar systems. Results: Over the course of 0.76 Myr the simulation forms more than 500 protostars, primarily within two sub-clusters. Synthetic SEDs are used to the calculate evolutionary tracers Tbol and Lsmm/Lbol. It is shown that, while the observed distributions of the tracers are well matched by the simulation, they generally do a poor job of tracking the protostellar ages. Disks form early in the simulation, with 40 % of the Class 0 protostars being encircled by one. The flux emission from the simulated disks is found to be, on average, a factor of 6 too low relative to real observations. The distribution of protostellar luminosities spans more than three order of magnitudes, similar to the observed distribution. Cores and protostars are found to be closely associated with one another, with the distance distribution between them being in excellent agreement with observations. Conclusions: The analysis and statistical comparison of synthetic observations to real ones is established as a powerful tool in the interpretation of observational results.