The initial conditions of high-mass star formation: radiative transfer models of IRDCs seen in the Herschel Hi-GAL survey

TL;DR

This study uses Herschel observations and radiative transfer models to analyze the properties of dense cores in IRDCs, shedding light on early high-mass star formation stages.

Contribution

First detailed radiative transfer modeling of IRDC cores with Herschel data to determine their physical properties and evolutionary status.

Findings

Core masses range from 90 to 290 solar masses.

Core temperatures are between 8 and 11K at the center.

High-mass star formation is unlikely in three cores.

Abstract

The densest infrared dark clouds (IRDCs) may represent the earliest observable stage of high-mass star formation. These clouds are very cold, hence they emit mainly at far-infrared and sub-mm wavelengths. For the first time, Herschel has provided multi-wavelength, spatially resolved observations of cores within IRDCs, which, when combined with radiative transfer modelling, can constrain their properties, such as mass, density profile and dust temperature. We use a 3D, multi-wavelength Monte Carlo radiative transfer code to model in detail the emission from six cores in three typical IRDCs seen in the Hi-GAL survey (G030.50+00.95, G031.03+00.26 and G031.03+00.76), and thereby to determine the properties of these cores and compare them with their low-mass equivalents. We found masses ranging from 90 to 290 solar masses with temperatures from 8 to 11K at the centre of each core and 18 to 28K at the surface. The maximum luminosity of an embedded star within each core was calculated, and we rule out the possibility of significant high mass star formation having yet occurred in three of our cores.