3D intergalactic map reveals details of dark matter, black holes and stars
The first 3D map of hundreds of galaxies in the local universe should improve our understanding of the neighborhood galaxy and galaxy clusters, showing how they form and change over time.
The map, which covers three-quarters of the sky, should help scientists measure the distribution of gas and dark matter in the local universe, and gain a much better understanding of the processes involved in the formation and evolution of galaxies and the role black holes play in this galactic development.
The map was produced by the L-band Widefield ASKAP Legacy All-Blind Survey (WALLABY) using data from the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope in the Australian Outback.
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During its first phase, WALLABY covered 180 square degrees of the night sky, an area equivalent in size to 700 full moonand surveyed more than 600 galaxies.
That’s just a drop in the cosmic ocean compared to the quarter of a million galaxies WALLABY is estimated to catalog during its mission. These observations will form a detailed intergalactic map, prompting an investigation that cannot be carried out on a similar scale using only optical telescopes.
“If yours The Milky Way is between us and the galaxy we’re trying to observe, the sheer amount of stars and dust makes it incredibly difficult to see anything else,” Tobias Westmayer, a radio astronomer at the University of Western Australia’s International Center for Radio Astronomy Research (ICRAR), said in a statement. “These restrictions do not affect the WALLABY. This is one of the strengths of radio research; they can just peer through all the stars and dust in our Milky Way.”
The ASKAP radio telescope that hosts WALLABY operates eight hours a day in a very quiet radio zone in the remote Midwest region of Western Australia, allowing WALLABY to find narrow and faint astronomical signals without being exposed to radio interference.
WALLABY represents the first full 3D galactic survey conducted at this scale, and this first data release consists of more than 30 terabytes of data from each eight-hour day.
The advantage of a 3D map is that it can better show astronomers where galaxies are relative to each other, separating galaxies that may look close together but are actually separated in another dimension by millions of light years.
“WALLABY will allow us to directly map and detect hydrogen gas, the fuel for star formation,” study co-author Karen Lee-Waddell, director of the Australian SKA Regional Center and WALLABY project scientist, said in a statement. “With this data, astronomers can precisely group galaxies together to better understand how they affect each other when grouped together, providing insight into how galaxies form and change over time.”
The sheer scale of the WALLABY catalog is expected to lead to many new observations and discoveries, and its first release already reveals many galaxies never before seen in radio waves.
“Of the more than 600 galaxies measured so far, many have not been previously cataloged in any other wavelength range and are considered new discoveries,” Lister Staveley-Smith, principal investigator of WALLABY and co-author of the study, said in a statement. “So far, more than a dozen papers have been published describing new discoveries from these early observations.”
The recently published WALLABY study is presented in two papersboth published Nov. 15 in the journal Publications of the Astronomical Society of Australia.
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