Parkes H I observations of galaxies behind the southern Milky Way. I. The Hydra/Antlia region (l~ 266o to 296o)

As part of our program to map the large-scale distribution of galaxies behind the Milky Way, we used the Parkes 210 ft (64 m) radio telescope for pointed \normalsize H \footnotesize I observations of a sample of low surface-brightness (due to heavy obscuration) spiral galaxies selected from the deep optical Zone of Avoidance (ZOA) galaxy catalog in the Hydra/Antlia region (Kraan-Korteweg \cite{Kraan-2000a}). Searching a simultaneous velocity range of either 300 to 5500 km s^-1 or 300 to 10 500 km s^-1 to an rms level of typically 2-4 m Jy resulted in detections in 61 of the 139 pointings, leading to a total of 66 detections (an additional detection was made in a reference position, and two other pointings revealed two and four independent signals respectively). Except for 2 strong \normalsize H \footnotesize I emitters identified in the shallow Zone of Avoidance \normalsize H \footnotesize I survey (Henning et al. \cite{Henning}), all \normalsize H \footnotesize I detections are new. An analysis of the properties of the observed and detected galaxies prove that pointed \normalsize H \footnotesize I observations of highly obscured galaxies allow the tracing of a population of nearby, intrinsically large and bright spiral galaxies that otherwise would not be recovered. The new data identified a previously unrecognized nearby group at l ~ 287. ^o5, b ~ -9. ^o5, V ~ 1700 km s^-1, the continuation of the Hydra/Antlia filament on the opposite side of the Galactic plane, and helped to delimit a distinct void in the ZOA centered at 2000 km s^-1. Tables 1 and 2 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/391/887