First All-sky Map

The Australian Square Kilometre Array Pathfinder (ASKAP), a powerful telescope developed and operated by the country’s science agency CSIRO, has mapped over three million galaxies in a record 300 hours during its first all-sky survey. The initial results of this survey were published in the journal Publications of the Astronomical Society of Australia on 30 November 2020.

ASKAP is a telescope designed over a decade ago and located about 800 km north of Perth. It became fully operational in February 2019 and is currently conducting pilot surveys of the sky before it can begin large-scale projects from 2021 onward.

ASKAP surveys are designed to map the structure and evolution of the Universe, which it does by observing galaxies and the hydrogen gas that they contain.

One of its most important features is its wide field of view, because of which it has been able to take panoramic pictures of the sky in great detail. The telescope uses novel technology developed by CSIRO, which is a kind of a “radio camera” to achieve high survey speeds and consists of 36 dish antennas, which are each 12m in diameter.

Using this telescope at CSIRO’s Murchison Radio-astronomy Observatory (MRO) in outback Australia, the survey team has been able to observe over 83 per cent of the sky visible from ASKAP’s site in Western Australia. For the current survey, it combined over 903 images to form the full map of the sky.

Essentially, the telescope has been able to map a vast area of the universe, something that would otherwise take close to a decade.

Significance of the results

The present Rapid ASKAP Continuum Survey (RACS) taken by the ASKAP telescope is like a “Google mapof the Universe where most of the millions of star-like points are distant galaxies, about a million of which have not been seen before. Mapping the Universe on such a scale enables astronomers to study the formation of stars and how galaxies and their supermassive black holes evolve and interact with each other.

Significantly, the images the telescope has taken are on average deeper and have better spatial resolution compared to those taken during other surveys of the sky. The aim of the RACS survey is to generate images that will aid future surveys undertaken using the telescope.

Further, the results of various surveys undertaken using ASKAP are also being used for the development of the Square Kilometre Array (SKA), which is an international project with the aim of building the world’s largest radio telescopes.

The results of this survey are significant for mainly two reasons. Firstly, the time it has taken ASKAP to map the Universe demonstrates that it is something that does not have to take years and secondly, the data that has been gathered as a result of the survey will help astronomers to undertake statistical analyses of large populations of galaxies.

Today is a special day for astronomy as we release the results of our ASKAP telescope’s first survey of the southern sky. What used to take years can now be done in days revealing more of the Universe – about a million times more!” CSIRO said.

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