WALLABY builds an intergalactic map in the outback

By on November 15, 2022 0

A radio telescope in a remote area of ​​Western Australia is helping create a 3D map of the night sky, mapping nearby galaxies up to a billion light-years away.

Published today in the Publications of the Astronomical Society of AustraliaThe WALLABY pilot survey (The Widefield ASKAP L-band Legacy All-sky Blind surveY) will share its first release of data with the scientific community, helping us better understand nearby galaxies and galactic clusters.

Hundreds of galaxies were surveyed in WALLABY Phase 1, covering 180 square degrees of the observable sky, the area equivalent to over 700 full moons.

During the survey, a quarter of a million galaxies are expected to be cataloged, helping researchers measure the distribution of dark matter, the internal motion of galaxies, and how these systems evolve and interact.

Lead author Dr Tobias Westmeier, from the University of Western Australia’s Node of the International Center for Radio Astronomy Research (ICRAR/UWA) and the ARC Center of Excellence for 3-Dimensional Sky Astrophysics ( ASTRO 3D), said the data collected by WALLABY will help us study the Universe on a scale we never could with simple optical telescopes.

“If our own Milky Way lies between us and the galaxy we’re trying to observe, the sheer number of stars and dust makes it incredibly difficult to see anything else,” Dr Westmeier said.

“WALLABY is not affected by these limitations. This is one of the great strengths of radio polls; they can just look through all the stars and dust in our own Milky Way.

It is the first comprehensive 3D survey of this scale, with more than 30 terabytes of data collected each eight-hour day from the ASKAP radio telescope in the remote Mid West region of Western Australia.

Co-author, WALLABY project scientist and director of the Australian SKA Regional Center Dr Karen Lee-Waddell said the project will show us where these galaxies really are relative to each other in three-dimensional space, dividing the galaxies that seem clustered together but millions of light-years apart.

“WALLABY will allow us to directly map and detect hydrogen gas, the fuel for star formation,” Dr Lee-Waddell said.

“With this data, astronomers can precisely group galaxies to better understand how they affect each other when grouped together, providing insight into how galaxies form and change over time.”

The WALLABY catalog is expected to lead to many new sightings and discoveries due to the sheer breadth of the investigation.

“Of the more than 600 galaxies measured so far, many have never been cataloged in another frequency band and are considered new discoveries,” said lead researcher and WALLABY co-author Professor Lister Staveley-Smith (ICRAR/UWA).

“More than a dozen papers have been published so far describing new findings from these early observations.”
CSIRO Australia’s National Telescope Facility Science Program Manager, Dr George Heald, said the projects were made possible by ASKAP’s ability to collect data on a scale never seen before.

“Our observatory is one of the quietest places in the world, allowing projects like WALLABY to find narrow, weak astronomical signals without being overwhelmed by radio interference,” Dr Heald said.

The international project works with organizations such as AusSRC, the Canadian Astronomical Data Center (run by the National Research Council of Canada) and CSIRO as well as many international universities to help process and catalog the data into a database. data usable for astronomers.

Professor Kristine Spekkens of Queens University and the Royal Military College of Canada is a co-author of the paper and an executive member of the WALLABY team.

“Astronomy in general, and WALLABY in particular, benefits from the contributions of researchers around the world to achieve scientific breakthroughs,” Professor Spekkens said.


‘WALLABY Pilot Survey: Public release of HI data for near 600 galaxies from phase 1 of ASKAP pilot observations’ and ‘WALLABY Pilot Survey: Public release of HI kinematic models for more than 100 galaxies from phase 1 of ASKAP pilot observations’, both published in Publications of the Astronomical Society of Australia on November 15, 2022.



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The Widefield ASKAP L-band Legacy All-sky Blind (or WALLABY) is a survey performed on the ASKAP radio telescope. WALLABY is a collaborative effort of nearly 200 researchers led by ICRAR, ASTRO 3D and CSIRO, and is one of nine surveys undertaken with ASKAP.


The ASK The radio telescope is located at Inyarrimanha Ilgari Bundara, the CSIRO Murchison radio astronomy observatory, one of the quietest places in the world. ASKAP is part of CSIRO’s Australia National Telescope Facility (ATNF) which also operates Parkes’ famous Murriyang radio telescope.

We acknowledge the Wajarri Yamatji as the traditional owners and native title holders of the Inyarrimanha Ilgari Bundara, the site of the CSIRO Murchison radio astronomy observatory where ASKAP is located.


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