Observations of Blue/Emission-Line Galxies \\from the Case Survey

Previous abstract Next abstract

Session 31 -- Star-Forming Galaxies
Display presentation, Tuesday, 9:30-6:30, Heller Lounge Room

[31.06] Observations of Blue/Emission-Line Galxies \\from the Case Survey

J.L. Rosenberg, J.J. Salzer (Wesleyan U.), J.W. Moody (BYU)

We present the results of our imaging and spectroscopic study of a complete sample of galaxies cataloged in the first two lists of the Case Low-Dispersion Northern Sky Survey. This sample of 176 objects was selected for detailed follow-up investigation in part because they are located in fields which overlap the \lq\lq Slice of the Universe" survey of de\thinspace Lapparent et al. (1986). We have obtained redshifts for the entire sample of objects, optical spectra for 141 galaxies including all of the line-selected subsample, and CCD images for 112 galaxies including all objects fainter than the limiting magnitude of the CGCG. We present a detailed description of the properties of the survey constituents, and compare the Case Galaxies with their counterparts in other objective-prism surveys. An analysis of the completeness limit for the survey is presented along with a derivation of the luminosity function and spatial distribution characteristics of these star-forming galaxies. We find that the unique selection characteristics of this sample allows it to find star-forming galaxies with lower levels of activity than those in purely line-selected surveys. We utilize the great depth of the redshift sample of normal galaxies in this field to study the relative spatial distributions of the CGCG and Case galaxies. The goals of this latter portion of our study are (i) to investigate the role that galaxy--galaxy encounters might play in triggering star formation; (ii) to assess the utility of using line/UV-excess selected galaxies to map out large scale structures at high redshift; (iii) to look for evidence of biasing in the spatial distribution of low-luminosity galaxies, which are more readily detected in objective-prism surveys than in magnitude-limited surveys.

Tuesday program listing