Australia Telescope National Facility

The HI Parkes Zone of Avoidance Shallow Survey
P. A. Henning , L. Staveley-Smith , R. C. Kraan-Korteweg , E. M. Sadler, PASA, 16 (1), in press.

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Title/Abstract Page: The HI Parkes Zone
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Contents Page: Volume 16, Number 1

Subsections

The Shallow Survey

Observing Strategy

The HI Parkes ZOA survey covers the southern ZOA (

$212\deg \le l \le 36\deg; \vert b \vert \le 5\deg$ ) over the velocity range (cz) = -1200 to

$12700\,\rm\,km\,s^{-1}$ . The multibeam receiver is a focal plane array with 13 beams arranged in an hexagonal grid. The spacing between adjacent beams is about two beamwidths, each beamwidth being 14 arcmin. The survey is comprised of 23 contiguous rectangular fields which are scanned parallel to the galactic equator. Eventually, each patch will be observed 25 times, with scans offset by about 1.5 arcmin in latitude. The shallow survey discussed here consists of two scans in longitude separated by $\Delta$ b = 17 arcmin, resulting in an rms noise of about 15 mJy, equivalent to a 5 $\sigma$ HI mass detection limit of 4 x 10⁶ d

$^2\!\!_{\rm Mpc}$ M $_{\odot}$ (for a galaxy with the typical linewidth of

$200{\,\rm\,km\,s^{-1}}$ ).

Data Visualization

After calibration, baseline-subtraction, and creation of data cubes, all done with specially developed routines based on aips++ (Barnes et al. 1998, Barnes 1998) the data are examined by eye using the visualization package Karma (http://www.atnf.csiro.au/karma/). The data are first displayed as right ascension - velocity planes, in strips of constant declination. Data cubes are then rotated, and right ascension - declination planes are checked for any suspected galaxies (eg. Figure 1).

**Figure 1:** Left panel shows a right ascension - velocity slice to 5000
${\,\rm\,km\,s^{-1}}$ which includes a galaxy discovered by the survey. Galactic HI appears as the strong horizontal feature at zero velocity. Note the extragalactic HI signal at

$7^{\rm h}18^{\rm m}$ ,

$900{\,\rm\,km\,s^{-1}}$ . Right panel shows a right ascension - declination plane at the velocity of the suspected signal. The galaxy is evident at

$7^{\rm h}18^{\rm m}$ , $-9\deg$ .
$\begin{figure} \begin{center} \hbox{ \psfig{file=map224avpart.eps,height=8.7cm} \psfig{file=map224ad.eps,height=8.7cm} } \end{center} \end{figure}$

Next Section: Galaxies Found by the
Title/Abstract Page: The HI Parkes Zone
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Contents Page: Volume 16, Number 1

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