article · The Astronomical Journal · 2026
The Column Density Probability Density Function of Cygnus-X
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Abstract
Abstract The density distribution within molecular clouds offers critical insights into their underlying physical processes, which are essential for understanding star formation. As a statistical measure of column density on the cloud scale, the shape and evolution of the column density probability density function (N-PDF) serve as important tools for understanding the dynamics between turbulence and gravity. Here, we investigate the N-PDFs of Cygnus-X using the column density map obtained from Herschel, supplemented by H I and young stellar objects data. We find that the N-PDFs of Cygnus-X and four subregions display log-normal + power-law shapes, indicating the combined effects of turbulence and gravity in sculpting the density structure. We find evidence that the power-law segment of the N-PDFs flattens over time, and the transitional column density can be seen as a unique and stable star formation threshold specific to each molecular cloud. These results not only clarify the physical state of Cygnus-X but also emphasize the utility of the N-PDF as a statistical diagnostic tool, as it is an accessible indicator of evolutionary stages and star formation thresholds in molecular clouds.
Cite this paper
Xing, Y., & Qiu, K. (2026). The Column Density Probability Density Function of Cygnus-X. The Astronomical Journal, 171(3), 152. https://doi.org/10.3847/1538-3881/ae331a
Xing, Yuchen, and Keping Qiu. “The Column Density Probability Density Function of Cygnus-X.” The Astronomical Journal, vol. 171, no. 3, 2026, p. 152, https://doi.org/10.3847/1538-3881/ae331a.
Xing, Yuchen, and Keping Qiu. 2026. “The Column Density Probability Density Function of Cygnus-X.” The Astronomical Journal 171 (3): 152. https://doi.org/10.3847/1538-3881/ae331a.
Xing, Y. and Qiu, K. (2026) ‘The Column Density Probability Density Function of Cygnus-X’, The Astronomical Journal, 171(3), p. 152. Available at: https://doi.org/10.3847/1538-3881/ae331a.
@article{xing2026column,
title = {{The Column Density Probability Density Function of Cygnus-X}},
author = {Xing, Yuchen and Qiu, Keping},
journal = {The Astronomical Journal},
volume = {171},
number = {3},
pages = {152},
year = {2026},
doi = {10.3847/1538-3881/ae331a}
}Made from the index record. Check names, capitalisation and page numbers against the paper. Need another style? AI for Research has over 10,000.