Data di Pubblicazione:
2015
Citazione:
Molecular clouds have power-law probability distribution functions / M. Lombardi, J. Alves, C.J. Lada. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 576(2015 Apr).
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.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
dust; extinction; ISM: clouds; ISM: structure; methods: data analysis; astronomy and astrophysics; space and planetary science
Elenco autori:
M. Lombardi, J. Alves, C.J. Lada
Link alla scheda completa: