Applying a one-dimensional PDR model to the Taurus molecular cloud and its atomic envelope

Abstract

In this contribution, we test our previously published one-dimensional PDR model for deriving total hydrogen volume densities from HI column density measurements in extragalactic regions by applying it to the Taurus molecular cloud, where its predictions can be compared to available data. Also, we make the first direct detailed comparison of our model to CO(1-0) and far-infrared emission. Using an incident UV flux G0 of 4.25 (χ = 5) throughout the main body of the cloud, we derive total hydrogen volume densities of \approx 430 cm-3, consistent with the extensive literature available on Taurus. The distribution of the volume densities shows a log-normal shape with a hint of a power-law shape on the high density end. We convert our volume densities to H2 column densities assuming a cloud depth of 5 parsec and compare these column densities to observed CO emission. We find a slope equivalent to a CO conversion factor relation that is on the low end of reported values for this factor in the literature (0.9 x 1020 cm-2 (K km s-1)-1), although this value is directly proportional to our assumed value of G0 as well as the cloud depth. We seem to under-predict the total hydrogen gas as compared to 100 μm dust emission, which we speculate may be caused by a higher actual G0 incident on the Taurus cloud than is generally assumed.

14 pages, 14 figures. Accepted for publication in MNRAS

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Cited by in corpus (5)

• The FRIED grid of mass loss rates for externally irradiated protoplanetary discs
• Assessing molecular line diagnostics of triggered star formation using synthetic observations
• Molecular cloud formation as seen in synthetic Hi and molecular gas observations
• A panoptic view of the Taurus molecular cloud I. The cloud dynamics revealed by gas emission and 3D dust
• Photon-Dominated Region Modeling of the [C I],[C II], and CO Line Emission from a Boundary in the Taurus Molecular Cloud