A Self-Absorption Census of Cold H I Clouds in the Canadian Galactic Plane Survey

摘要: We present a 21 cm line H I self-absorption (HISA) survey of cold atomic gas within Galactic longitudes l = 75? to 146? and latitudes b -3? +5?. identify HISA as spatially spectrally confined dark features extract it from the surrounding emission in arcminute-resolution Canadian Plane Survey (CGPS). compile catalog most significant our compare detections against those literature. Within parameters search, we find nearly all previously detected many new ones. The CGPS shows much greater detail than any prior allows both discovered be placed into larger context structure. In space radial velocity, faint is virtually everywhere that background sufficiently bright. This ambient population may arise small turbulent fluctuations temperature velocity neutral interstellar medium. By contrast, stronger organized discrete complexes, which follow longitude-velocity distribution suggests they have been made visible by reversal Perseus arm's spiral density wave. revealed this way recently passed through shock on its forming molecules and, eventually, stars. paper second series examining at high angular resolution. A companion (Paper III) describes search extraction algorithms detail.