The H I Parkes All Sky Survey (HIPASS) is a large survey for neutral atomic hydrogen (H I). Most of the data was taken between 1997 and 2002 using CSIRO's 64 m

Parkes Telescope Parkes Observatory is a radio astronomy observatory, located north of the town of Parkes, New South Wales, Australia. It hosts Murriyang, the 64 m CSIRO Parkes Radio Telescope also known as "The Dish", along with two smaller radio telescopes. T ...

. HIPASS covered 71% of the sky and identified more than 5000 galaxies; the major galaxy catalogs are: the "HIPASS Bright Galaxy Catalog" (HIPASS BGC), the southern HIPASS catalog (HICAT), and the northern HIPASS catalog (NHICAT) Discoveries include over 5000 galaxies (incl. several new galaxies), the Leading Arm of the Magellanic Stream and a few gas clouds devoid of

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

Survey

HIPASS covers a velocity range of −1,280 to 12,700 km/s. It was the first blind HI survey to cover the entire southern sky and the northern sky up to +25°. Technical overview, calibration and imaging (Barnes et al. 2001).

Southern Sky observations

Observations of the southern sky started in February 1997, and were completed in March 2000, consisting of 23,020 eight-degree scans of each of 9 minutes duration. HIPASS scanned the entire southern sky five times. The southern HIPASS galaxy catalog (HICAT) contains 4315 HI sources.

Northern Sky observations

Northern HIPASS extended the survey into the northern sky. The entire Virgo Cluster region was observed in Northern HIPASS. NHICAT, the catalogue of the northern extension of HIPASS contains 1,002 H I sources.

CHIPASS

Archival data from HIPASS and the HI Zone of Avoidance (HIZOA) survey were reprocessed to make a new 20cm confusion-limited continuum map of the sky south of

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

+25°. Its relatively high

sensitivity Sensitivity may refer to: Science and technology Natural sciences * Sensitivity (physiology), the ability of an organism or organ to respond to external stimuli ** Sensory processing sensitivity in humans * Sensitivity and specificity, statisti ...

and resolution (compared to other single-dish surveys) and low level of artefacts has made this survey invaluable, particularly for merging with interferometric data such as WALLABY to improve the coverage of extended structure.

Multibeam Receiver

Observations for HIPASS were taken using the Parkes 21-cm Multibeam Receiver. The instrument consists of a focal-plane array of 13 individual receivers arranged in a hexagonal pattern. Built in a collaboration between numerous institutions, it was funded by the

Australian Research Council The Australian Research Council (ARC) is the primary non-medical research funding agency of the Australian Government, distributing more than in grants each year. The Council was established by the ''Australian Research Council Act 2001'', ...

(ARC) and the Australia Telescope National Facility (ATNF) to undertake the HIPASS and ZOA surveys.

Discoveries

Leading arm of Magellanic Stream

HIPASS discovered the Leading Arm of the Magellanic Stream. This is an extension of the Magellanic Stream beyond the Magellanic clouds. The existence of the Leading Arm is predicted by models of a tidal interaction between the Magellanic Clouds and the Milky Way.

HIPASS J0731-69

HIPASS J0731-69 is a cloud of gas devoid of any stars. It is associated with the asymmetric spiral galaxy NGC 2442. It is likely that HIPASS J0731-69 was torn loose from NGC 2442 by a companion.

HIPASS J1712-64

HIPASS J1712-64 is an isolated extragalactic cloud of neutral hydrogen with no associated stars. The cloud is a binary system and is not dense enough to form stars. HIPASS J1712-64 was probably ejected during an interaction between the Magellanic clouds and the Milky way.

New galaxies in the Centaurus A/M83 Group

Ten new galaxies were identified in the

Centaurus A/M83 Group The Centaurus A/M83 Group is a complex group of galaxies in the constellations Hydra, Centaurus, and Virgo. The group may be roughly divided into two subgroups. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered on Centauru ...

, bringing the total (at the time) to 31 galaxies.

References

{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Astronomical imaging Astronomical surveys