Linking simulations and observations of star-forming regions I. Masses and temperatures of ALMAGAL-like cores

Abstract

Dense cores and clumps in massive star-forming regions are studied through (sub-)millimetre continuum observations, but inferred masses and temperatures can be biased by limited resolution, interferometric filtering, projection, and uncertain dust temperatures. We quantify how reliably core masses and temperatures can be inferred from ALMA-like continuum data using synthetic observations of such clumps. We post-processed radiation-hydrodynamic simulations of collapsing 1000 M${}_{\odot }$ clumps with RADMC-3D and CASA to generate synthetic ALMAGAL-like images. Cores were defined around sink particles, enabling comparison of masses from the 3D simulations, idealised RADMC-3D maps, and synthetic ALMA images. We quantified how resolution, projection, and viewing angle affect core masses, and tested three dust-temperature estimators (clump-scale L/M, a L/M+flux model, and a supervised machine-learning estimate). Projection effects cause line-of-sight integrated core masses within 1500 au to exceed spherical masses by factors of two to three. The empirical L/M temperature prescription follows the global thermal evolution but misses the core-to-core scatter, producing core-mass errors of a factor of a few. Including local flux improves temperature and mass estimates, while a gradient-boosting machine-learning model suggests further improvement. Synthetic ALMAGAL-like images recover the global core structure, but flux-reconstruction uncertainties introduce mass errors up to a factor of three and limit reliable core-mass recovery to $\gtrsim 0.3$ M${}_{\odot }$, comparable to the ALMAGAL completeness limit. Individual core masses are typically uncertain by a factor of three to five, mainly due to dust-temperature assumptions and flux reconstruction. Reducing these biases requires temperature estimates that include local core information rather than a single clump-scale L/M-based prescription.

References in corpus (21)

• CASA, the Common Astronomy Software Applications for Radio Astronomy
• High-Mass Star and Massive Cluster Formation in the Milky Way
• The Effects of Radiative Transfer on Low-Mass Star Formation
• The relative impact of photoionizing radiation and stellar winds on different environments
• Tree-based solvers for adaptive mesh refinement code FLASH - I: gravity and optical depths
• Calibration of evolutionary diagnostics in high-mass star formation
• Zooming in on Individual Star Formation: Low- and High-mass Stars
• A Novel High-Order, Entropy Stable, 3D AMR MHD Solver with Guaranteed Positive Pressure
• How fast do young star clusters expel their natal gas?: Estimating the upper limit of the gas expulsion time-scale
• Synthetic observations of star formation and the interstellar medium
• The SQUALO project (Star formation in QUiescent And Luminous Objects) I: clump-fed accretion mechanism in high-mass star-forming objects
• Observing Turbulent Fragmentation in Simulations: Predictions for CARMA and ALMA
• Tree-based solvers for adaptive mesh refinement code FLASH -- II: radiation transport module TreeRay
• Modelling the chemistry of star-forming filaments - II. Testing filament characteristics with synthetic observations
• Insights from Synthetic Star-forming Regions: I. Reliable Mock Observations from SPH Simulations
• Will ALMA Reveal the True Core Mass Function of Protoclusters?
• ALMAGAL IV. Morphological comparison of molecular and thermal dust emission using the histogram of oriented gradients (HOG) method
• Tree-based solvers for adaptive mesh refinement code FLASH -- III: a novel scheme for radiation pressure on dust and gas and radiative transfer from diffuse sources
• ALMAGAL VI. The spatial distribution of dense cores during the evolution of cluster-forming massive clump
• ALMAGAL V. Relations between the core populations and the parent clump physical properties
• ALMAGAL VII. Cataloging Hierarchical Mass Structure from Cores to Clumps across the Galactic Disk