Interpretation of CO emission from the galactic molecular cloud ensemble

Abstract

view Abstract Citations (70) References (24) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Interpretation of CO emission from the galactic molecular cloud ensemble Liszt, H. S. ; Burton, W. B. Abstract An analysis is presented of simulated observations of CO emission from a model ensemble of molecular clouds in the inner Galaxy. The model galaxy is constructed in a three-dimensional manner, with each cloud assigned a position and systematic velocity according to specified distribution laws, and the observations are simulated for circular Gaussian telescope beams of different sizes and sampling intervals. Results are presented in the form of longitude-velocity diagrams for models of various cloud numbers, sizes, velocity distributions and kinematic perturbations. The typical cloud diameter in the inner Galaxy is found to be 15-20 pc, with larger clouds containing not more than 50% of the total cloud volume, while many of the large complex features observed in CO emission maps are shown to be the result of the blending of physically unrelated clouds. Results indicate that even though the molecular clouds fill a very small fraction of the galactic layer, they are sufficiently abundant that the gas distribution in the inner Galaxy must be dominated by molecular matter. Finally, the collective emission pattern in the Galactic plane is found to be very susceptible to kinematic perturbations, and kinematic patterns usually ascribed to spiral density enhancements are shown to arise mainly through velocity projection effects. Publication: The Astrophysical Journal Pub Date: February 1981 DOI: 10.1086/158646 Bibcode: 1981ApJ...243..778L Keywords: Carbon Monoxide; Galactic Radiation; Interstellar Gas; Molecular Clouds; Molecular Gases; Antenna Radiation Patterns; Astronomical Models; Galactic Structure; Telescopes; Velocity Distribution; Astrophysics full text sources ADS |