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We examine the issues surrounding an IR slitless prism survey for galaxies with highly redshifted Hα to see if some of the next generation of IR instruments should have the capability to conduct such surveys. We model the galaxy and star surface density as a function of J, H, and K magnitudes to estimate field crowding with depth. Using data from the Subaru 8.2 m telescope and Infrared Camera and Spectrograph detector as a benchmark, we estimate the number of detectable galaxies as a function of telescope aperture size, object magnitude, and line strength. We find that while crowding need not be a major problem, it is still difficult for even a large telescope to obtain a useful emission-line galaxy sample in the J, H, or K bands primarily because of the high IR background and the faintness of the galaxies with Hα in these bands.

We examine the population statistics for two samples of galaxies in the direction of the Perseus supercluster. One sample, with N = 258 galaxies having MB ≤ -19.52 + 5 log(h) and vh ≤ 8000 km s-1, is complete for those galaxies within the boundaries of our survey region that have apparent magnitudes mp ≤ 15.0 in the Zwicky catalog. A more restrictive sample with N = 177 galaxies having MB ≤ -20.00 + 5 log(h) (with the same redshift range) is complete in both luminosity and volume. We derive the statistics for the relative incidence of galaxies in the following spectroscopic classes: (1) absorption line only, (2) collisionally-excited emission lines only, (3) nuclear H II region, (4) starburst, (5) LINER, and (6) Seyfert 1.8–2.

We present new optical spectroscopic data for 347 galaxies in the region of the Perseus supercluster. The new data were obtained using the Steward Observatory 2.3 m telescope and cover the whole optical window. Included are redshifts (for 345 objects), absorption-line equivalent widths, a continuum index measuring the 4000 A break, and emission-line flux ratios. After 11 objects are rejected for being too faint and redshifts for 26 objects are added from the literature, we arrive at a complete sample of 361 galaxies. The distribution of redshifts for the whole sample is examined, and we show the relationship of the continuum index to morphology.

The paper reports on VLA 20 cm observations of an extensive sample of galaxies in 139 poor groups. These groups, composed of galaxies down to the limit of the Zwicky et al. (CGCG) catalog, were chosen using a percolation algorithm set at a high surface-density threshold. Approximately 50 percent of the groups have measured redshifts. These groups were surveyed using a snapshot mode of the VLA with a resolution of about 13 arcsec. Analysis of the resulting radio and optical properties reveals that the presence of a nearby companion galaxy has an important role in generating radio emission in a galaxy. CCD observations of two radio-loud, disturbed galaxies with companions are presented and are used to discuss models of radio-source production. Nine tailed radio galaxies are found in the poor groups, which is much more than had been expected from previous work on rich clusters and from theoretical models. The paper discusses previous statistical biases and proposes a method for bending head-tail sources in poor groups. From the confinement of extended radio features associated with tailed sources, the presence of a substantial intracluster medium that should radiate significantly at soft-X-ray energies is predicted. 56 references.

VLA 20-cm continuum observations of eight emission-line galaxies in the Bootes void are presented. Five of the eight galaxies have weak (0.7-4.4 mJy) and compact radio emission. The radio and optical properties of these galaxies are compared with those of Seyferts and starburst galaxies in an effort to understand the origin and nature of galaxy activity in such an underdense region. It is concluded that the radio and optical properties of these galaxies are remarkably similar to those of active galaxies in richer cluster environments. 22 references.