The density structure of molecular cloud scales: A fitting for N-PDF with multi log-normal functions
Abstract
We studied the probability distribution function of the column density (N-PDF) of molecular clouds based on a fit with a multi-log-normal function using the Nobeyama 45-m Cygnus X CO survey data. We identified 124 molecular clouds in 13CO data using the DENDROGRAM and SCIMES algorithms. The N-PDF was constructed for 11 extended (≥ 0.4 deg2) molecular clouds of these identified clouds. We found that every N-PDF is well-fitted with one or two log-normal (LN) distributions. We investigated the distributions of the column density, C18O dense cores, and radio continuum source in each cloud and found that the N-PDF was less correlated with the star-forming activity. The LN N-PDF parameters showed two impressive features. First, the LN distribution at the low-density part had the same mean column density (∼1021.5 cm−2 ) for almost all the molecular clouds. Second, the wider LN distribution tended to show the lower mean density of the structures.
- Publication:
-
Resolving the Rise and Fall of Star Formation in Galaxies
- Pub Date:
- 2023
- DOI:
- 10.1017/S1743921322004379
- Bibcode:
- 2023IAUS..373...45M
- Keywords:
-
- ISM: clouds;
- ISM: structure;
- ISM: molecules;
- methods: analytical;
- stars: formation