Exponential Tails in the Centroid Velocity Distributions of Star-forming Regions

Exponential Tails in the Centroid Velocity Distributions of Star-Forming Regions

Probability density functions (pdfs) of CO emission line centroid (line-of-sight, intensityweighted average) velocities are presented for several densely sampled molecular clouds as quantitative descriptors of their underlying dynamics. Although some are approximately Gaussian in form, most of the pdfs exhibit relatively broader, often nearly exponential, tails, similar to the pdfs of velocity ...

Velocity Field Statistics in Star-forming Regions. I. Centroid Velocity Observations

The probability density functions (pdfs) of molecular line centroid velocity fluctuations, and of line centroid velocity fluctuation differences at different spatial lags, are estimated for several nearby molecular clouds with active internal star formation. The data consist of over 75,000 CO line profiles divided among twelve spatially and/or kinematically distinct regions. These regions range...

The Chemistry of Star-Forming Regions

During the last quarter century, chemists have responded magnificently to the challenges raised by astronomers in their attempts to understand the variety of molecules detected in interstellar clouds. Observations have shown the chemistry of these regions to be surprisingly complex, and now more than 100 molecular species have been identified in interstellar and circumstellar regions of the Gal...

The metallicity of circumnuclear star forming regions

We present a spectrophotometric study of circumnuclear star forming regions (CNSFR) in the early type spiral galaxies: NGC 2903, NGC 3351 and NGC 3504, all of them of over solar metallicity according to standard empirical calibrations. A detailed determination of their abundances is made after careful subtraction of the very prominent underlying stellar absorption. It is found that most regions...

Observations of Infall in Star-forming Regions