HIPASS Surveys

  
Table 1: Summary of the the expected parameters of the two major HIPASS surveys.

The scientific goals of the HIPASS surveys and a technical description of the receiver have been outlined elsewhere (Staveley-Smith et al. 1996). The approximate parameters of the surveys, as envisaged by the Multibeam Survey Working Group, are given in Table 1 for reference. This table contains the expected parameters for the HIPASS surveys, and an estimate of the theoretical detection limits. These detection limits will not be verified until the multibeam receiver is commissioned. The volume coverage is compared with previous and other continuing surveys by Schneider (1997). Other Parkes multibeam surveys, including a deep survey (see Disney & Banks 1997), are also proposed.

The first HIPASS survey, the Southern-Sky Survey is fairly shallow with an effective integration time of around 500 s for each beam area. Assuming that Nyquist sampling is desirable so that accurate positions can be obtained and extended structure can be faithfully reproduced, then about four pointings for each beam area are required. This implies a relatively short observing time for each point (125 s) and means that telescope control overheads will be very significant if the traditional point-and-shoot observing technique is used. Therefore a slow (active or drift) scan of the telescope across the sky, with continuous data collection, is probably the best observing technique for this survey (Sections 3.2 and 4).

The Zone of Avoidance survey is deeper, with an effective integration time of approximately 1800 s for each beam area; therefore, the choice of observing technique is not as constrained. At this stage (prior to commissioning), it is expected that a point-and-shoot technique (Section 3.1) will be used, in order to accommodate a piggy-back Galactic Plane pulsar survey. For sky-subtraction purposes, the telescope position will be frequently switched between adjacent fields (Section 4).

© Copyright Astronomical Society of Australia 1997