Cloud Structure and Physical Conditions in Star-forming Regions from Optical Observations. I. Data and Component Structure

Abstract

We present high-resolution optical spectra (at ~0.6--1.8 km s-1) of interstellar CN, CH, CH^+, \ion{Ca}{1}, \ion{K}{1}, and \ion{Ca}{2} absorption toward 29 lines of sight in three star-forming regions, ρOph, Cep OB2, and Cep OB3. The observations and data reduction are described. The agreement between earlier measurements of the total equivalent widths and our results is quite good. However, our higher resolution spectra reveal complex structure and closely blended components in most lines of sight. The velocity component structure of each species is obtained by analyzing the spectra of the six species for a given sight line together. The tabulated column densities and Doppler parameters of individual components are determined by using the method of profile fitting. Total column densities along lines of sight are computed by summing results from profile fitting for individual components and are compared with column densities from the apparent optical depth method. A more detailed analysis of these data and their implications will be presented in a companion paper.

66 pages, 15 figures, accepted to ApJS

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• High-Resolution Observations of Interstellar Ca I Absorption -- Implications for Depletions and Electron Densities in Diffuse Clouds
• Observations of Small Scale ISM Structure in Dense Atomic Gas
• Density Variations over Subparsec Scales in Diffuse Molecular Gas
• Physical Conditions in the Foreground Gas of Reflection Nebulae: NGC 2023, vdB 102, and NGC 7023

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