Star gazers will fill space in our knowledge of the universe

Two Swinburne University astronomers will use one of world’s best telescopes to unlock information on six million galaxies.

Guardians of the galaxies: Swinburne University astronomers Michelle Cluver and Edward Taylor will use of the world’s best telescopes to make a gravitational map of the near universe. Photo: David Geraghty

Two Swinburne University astronomers are embarking on a major project that will unlock a flood of information on six million galaxies in the sector of the universe nearest our Milky Way galactic home.

Edward Taylor and Michelle Cluver, both associate professors at Swinburne, are leading a multi-national 70-strong team to carry out the work using the European Southern Observatory’s 4MOST telescope facility in Chile.

Over five years, starting in 2024, the telescope will gather data from every one of the six million target galaxies, plugging a massive gap in astronomical knowledge.

While the new James Webb Space Telescope, launched last year, is amazing the world with images of early galaxies more than 13 billion light years away, we still lack key information about the galaxies in our “local” area, up to three billion light years away.

Measurements sought by Professor Taylor and Professor Cluver include each galaxy’s distance from us, its velocity and its mass.

“By measuring the mass and the motion, we’re going to get a complete gravitational map of the southern universe,” Professor Taylor said.

Their work, particularly the measurement of distance to each galaxy, will be the key to interpreting a host of other observations of galaxies made by other astronomy platforms such as the Square Kilometre Array radio telescope, the new Vera Rubin Legacy Survey of Space and Time, the European Space Agency’s planned Euclid space telescope and the now decommissioned NASA satellite, the Wide-field Infrared Survey Explorer.

“All those different data sources tell you different things (about galaxies). But without the distance you don’t have access to any of those pieces of information,” Professor Taylor said. “Without that distance information, those big facilities are blind to what’s right in front of them.”

While galaxies visible from the northern hemisphere are already being mapped in a US-based project costing $75m, the effort at Swinburne is low-cost.

“We had to work out how we could do it on a much smaller budget,” Professor Cluver said. She said they were fortunate to be able to plug into the existing infrastructure at the European Southern Observatory.

“If we had to do this by ourselves, there’s no way we could do it. We just don’t have the resources,” Professor Cluver said.

To keep costs down the pair are using a joint Swinburne-Curtin University initiative – Astronomy Data and Computing Services – to help them accurately locate the galaxies, and they also have access to Swinburne’s super computer. Without that, Professor Taylor said, the project could not succeed.

Even though they lack big resources, the two astronomers still managed to get allocated 235 observation nights on the Chile telescope over the five-year period of the project. The telescope needs to gather light for 20 minutes from each of the six million target galaxies to obtain enough data about each one.

The recently upgraded 4MOST telescope, which the two astronomers are using, employs an Australian-developed robotic system called AESOP to efficiently capture and store information from thousands of stars and galaxies at once.

First, the telescope fixes on one sector of the sky and then tiny robots align 2448 optical fibres with the images of separate stars and galaxies visible in that sector. The system enables light to be gathered and analysed, and data saved, from 2448 target stars or galaxies simultaneously.