Work

Molecular clouds have power-law probability distribution functions

Year: 2015

Type: article

Abstract: In this Letter we investigate the shape of the probability distribution of column densities (PDF) in molecular clouds. Through the use of low-noise, extinction-calibrated Herschel/Planck emission data for eight molecular clouds, we demonstrate that, contrary to common belief, the PDFs of molecular clouds are not described well by log-normal functions, but are instead power laws with exponents close to two and with breaks between AK ≃ 0.1 and 0.2 mag, so close to the CO self-shielding limit and not far from the transition between molecular and atomic gas. Additionally, we argue that the intrinsic functional form of the PDF cannot be securely determined below AK ≃ 0.1 mag, limiting our ability to investigate more complex models for the shape of the cloud PDF.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/201525650

Authors: Marco Lombardi, João Alves, Charles J. Lada

Institutions: University of Milan, Center for Astrophysics Harvard & Smithsonian, University of Vienna

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: bronze

Funder: Ministero dell’Istruzione, dell’Università e della Ricerca

Award: G3653413569