AN H-I SURVEY OF THE BOOTES VOID .2. THE ANALYSIS

We discuss the results of a VLA(2) [Napier et al., Proc. IEEE 71, 1295 (1983)] H I survey of the Bootes void and compare the distribution an d H I properties of the void galaxies to those of galaxies found in a survey of regions of mean cosmic density. The Bootes survey covers 110 0 Mpc(3), or similar to 1% of the volume of the void and consists of 2 4 cubes of typically 2 MpcX2 MpcX1280 km s(-1), centered on optically known galaxies. Sixteen targets were detected in H I; 18 previously un cataloged objects were discovered directly in H I. The control samples consists of 12 cubes centered on IRAS-selected galaxies with FIR lumi nosities similar to those of the Bootes targets and located in regions of one to two times the cosmic mean density. In addition to the 12 ta rgets 29 companions were detected in H I. We find that the number of g alaxies within 1 Mpc of the targets is the same to within a factor of 2 for void and control samples, and thus that the small scale clusteri ng of galaxies is the same in regions that differ by a factor of simil ar to 6 in density an larger scales. A dynamical analysis of the galax ies in the void suggests that on scales of a few Mpc the galaxies are gravitationally bound, forming interacting galaxy pairs, loose pairs, and loose groups. One group is compact enough to qualify as a Hickson compact group (hereafter referred to as HCG [Hickson, APJ, 255, 382 (1 952)]. The galaxies found in the void are mostly late-type, gas-rich s ystems. A careful scrutiny of their H I and optical properties shows t hem to be very similar to field galaxies of the same morphological typ e. This, combined with our finding that the small scale clustering of the galaxies in the voids is the same as in the field, suggests that i t is the near environment that mostly affects the evolution of galaxie s. (C) 1996 American Astronomical Society.