EDP Sciences
Free access
Volume 391, Number 3, September I 2002
Page(s) 887 - 902
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20020884

A&A 391, 887-902 (2002)
DOI: 10.1051/0004-6361:20020884

Parkes H I observations of galaxies behind the southern Milky Way

I. The Hydra/Antlia region ( $l\approx$ 266 ${^\circ}$ to 296 ${^\circ}$)
R. C. Kraan-Korteweg1, P. A. Henning2 and A. C. Schröder3

1  Depto. de Astronomía, Universidad de Guanajuato, Apartado Postal 144, Guanajuato, Gto 36000, Mexico
2  Institute for Astrophysics, University of New Mexico, 800 Yale Blvd., NE, Albuquerque, NM 87131, USA
3  Dept. of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK

(Received 3 April 2002 / Accepted 11 June 2002)

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 $\ion{H}{I}$ 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 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 $\ion{H}{I}$ emitters identified in the shallow Zone of Avoidance $\ion{H}{I}$ survey (Henning et al. 2000), all $\ion{H}{I}$ detections are new. An analysis of the properties of the observed and detected galaxies prove that pointed $\ion{H}{I}$ 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 $\ell \sim 287\hbox{$.\!\!^\circ$ }5, b \sim-9\hbox{$.\!\!^\circ$ }5, V\sim 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.

Key words: catalogs -- surveys -- ISM: dust, extinction -- galaxies: fundamental parameters -- radio lines: galaxies -- cosmology: large-scale structure of the Universe

Offprint request: R. C. Kraan-Korteweg, kraan@astro.ugto.mx

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