THE DISTRIBUTION OF NEUTRAL HYDROGEN IN THE INTERSTELLAR-MEDIUM .1. THE DATA

We compile, from the existing literature, the largest sample to date ( 842 data points) of hydrogen column density measurements, N(H I), of t he gas in the interstellar medium. We include only results obtained fr om absorption measurements toward individual stars (594 in our sample) in an effort to construct a three-dimensional picture of the interste llar gas. We derive hydrogen column densities toward a fraction of the stars in the sample from published column density measurements of met al ions. A three-dimensional physical model derived from this data set will be presented in a companion paper. The observed stars span dista nces from a few parsecs to a few thousand parsecs, and more than half of the sample serves to describe the local interstellar medium within a few hundred parsecs of the Sun. Hydrogen column densities range from 10(17) to 10(22) cm-2. We describe here the various observational met hods used to estimate the hydrogen column densities and present the ta ble with the stellar and hydrogen column density data. The provided ta ble is intended as a global reference work, not to introduce new resul ts.