The Characterization and Galactic Distribution of Infrared Dark Clouds

Simon, R.; Rathborne, J. M.; Shah, R. Y.; Jackson, James M.; Chambers, E. T.

doi:10.1086/508915

Cited by 216 publications

(349 citation statements)

References 24 publications

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“…However, as the individual peaks cannot be seen at either 160 μm or 500 μm, the two are grouped together and modelled as a single core. A distance of 3.4 kpc for the entire cloud is assumed (Simon et al 2006b). No previously calculated masses are available for these cores.…”

Section: G03050+0095mentioning

confidence: 99%

“…Neither core can be seen in emission at wavelengths shorter than 160 μm. A distance of 3.4 kpc is assumed (Simon et al 2006b). No previously calculated masses are available for these cores.…”

Section: G03103+0076mentioning

confidence: 99%

“…Williams et al 2001;Simon et al 2006b;Rathborne et al 2006). In particular, in Rathborne et al (2006), masses of dark cores were calculated and found to vary from 10 to 2100 M .…”

Section: Core Massesmentioning

confidence: 99%

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

Wilcock

Kirk

Stamatellos

et al. 2011

A&A

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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 M with temperatures from 8 to 11 K at the centre of each core and 18 to 28 K 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.

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Section: G03050+0095mentioning

confidence: 99%

Section: G03103+0076mentioning

confidence: 99%

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

Wilcock

Kirk

Stamatellos

et al. 2011

A&A

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“…Carey et al 1998;Peretto & Fuller 2010) against the Galactic background at mid-IR wavelengths . Simon et al (2006a), Teyssier et al (2002), and Kainulainen et al (2011a) showed that some IRDCs are embedded in giant molecular clouds (GMCs), and thus are not isolated…”

Section: Introductionmentioning

confidence: 99%

Understanding star formation in molecular clouds

Schneider

Csengeri

Klessen

et al. 2015

A&A

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We analyse column density and temperature maps derived from Herschel dust continuum observations of a sample of prominent, massive infrared dark clouds (IRDCs) i.e. G11.11-0.12, G18.82-0.28, G28.37+0.07, and G28.53-0.25. We disentangle the velocity structure of the clouds using 13 CO 1→0 and 12 CO 3→2 data, showing that these IRDCs are the densest regions in massive giant molecular clouds (GMCs) and not isolated features. The probability distribution function (PDF) of column densities for all clouds have a power-law distribution over all (high) column densities, regardless of the evolutionary stage of the cloud: G11.11-0.12, G18.82-0.28, and G28.37+0.07 contain (proto)-stars, while G28.53-0.25 shows no signs of star formation. This is in contrast to the purely log-normal PDFs reported for near and/or mid-IR extinction maps. We only find a log-normal distribution for lower column densities, if we perform PDFs of the column density maps of the whole GMC in which the IRDCs are embedded. By comparing the PDF slope and the radial column density profile of three of our clouds, we attribute the power law to the effect of large-scale gravitational collapse and to local free-fall collapse of pre-and protostellar cores for the highest column densities. A significant impact on the cloud properties from radiative feedback is unlikely because the clouds are mostly devoid of star formation. Independent from the PDF analysis, we find infall signatures in the spectral profiles of 12 CO for G28.37+0.07 and G11.11-0.12, supporting the scenario of gravitational collapse. Our results are in line with earlier interpretations that see massive IRDCs as the densest regions within GMCs, which may be the progenitors of massive stars or clusters. At least some of the IRDCs are probably the same features as ridges (high column density regions with N > 10 23 cm −2 over small areas), which were defined for nearby IR-bright GMCs. Because IRDCs are only confined to the densest (gravity dominated) cloud regions, the PDF constructed from this kind of a clipped image does not represent the (turbulence dominated) low column density regime of the cloud.

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“…Simon et al (2006a) presented a catalog of almost 11 000 IRDCs in the first and fourth quadrants of the Galactic plane. Using 13 CO J = 1-0 molecular line emission, the kinematic distances to 313 clouds in this catalog were established (Simon et al 2006b). This allowed to estimate the sizes, masses, and Galactic distribution for this large sample.…”

Section: Introductionmentioning

confidence: 99%

Physical properties of Southern infrared dark clouds

Vasyunina

Linz

Henning

et al. 2009

A&A

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Context. What are the mechanisms by which massive stars form? What are the initial conditions for these processes? It is commonly assumed that cold and dense Infrared Dark Clouds (IRDCs) represent the birth-sites of massive stars. Therefore, these clouds have been receiving an increasing amount of attention, and their analysis offers the opportunity to tackle the afore mentioned questions. Aims. To enlarge the sample of well-characterised IRDCs in the southern hemisphere, where ALMA will play a major role in the near future, we have developed a program to study the gas and dust of southern infrared dark clouds. The present paper attempts to characterize the continuum properties of this sample of IRDCs. Methods. We cross-correlated 1.2 mm continuum data from SIMBA bolometer array mounted on SEST telescope with Spitzer/GLIMPSE images to establish the connection between emission sources at millimeter wavelengths and the IRDCs that we observe at 8 μm in absorption against the bright PAH background. Analysing the dust emission and extinction enables us to determine the masses and column densities, which are important quantities in characterizing the initial conditions of massive star formation. We also evaluated the limitations of the emission and extinction methods. Results. The morphology of the 1.2 mm continuum emission is in all cases in close agreement with the mid-infrared extinction. The total masses of the IRDCs were found to range from 150 to 1150 M (emission data) and from 300 to 1750 M (extinction data). We derived peak column densities of between 0.9 and 4.6 × 10 22 cm −2 (emission data) and 2.1 and 5.4 × 10 22 cm −2 (extinction data). We demonstrate that the extinction method is unreliable at very high extinction values (and column densities) beyond A V values of roughly 75 mag according to the Weingartner & Draine (2001) extinction relation R V = 5.5 model B (around 200 mag when following the common Mathis (1990, ApJ, 548, 296) extinction calibration). By taking the spatial resolution effects into account and restoring the column densities derived from the dust emission to a linear resolution of 0.01 pc, peak column densities of 3-19 × 10 23 cm −2 are obtained, which are much higher than typical values for low-mass cores. Conclusions. Taking into account the spatial resolution effects, the derived column densities are beyond the column density threshold of 3.0 × 10 23 cm −2 required by theoretical considerations for massive star formation. We conclude that the values of column densities derived for the selected IRDC sample imply that these objects are excellent candidates for objects in the earliest stages of massive star formation.

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The Characterization and Galactic Distribution of Infrared Dark Clouds

Cited by 216 publications

References 24 publications

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

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

Understanding star formation in molecular clouds

Physical properties of Southern infrared dark clouds

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