What ingredients went into the galactic blender to create the Milky Way?

Our galaxy is a giant ‘smoothie’ of blended stars and gas but a new study tells us where the components came from

In its early days, the Milky Way was like a giant smoothie, as if galaxies consisting of billions of stars, and an enormous amount of gas had been thrown together into a gigantic blender. But a new study picks apart this mixture by analysing individual stars to identify which originated inside the galaxy and which began life outside.

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Too much heavy metal stops stars producing

Stars evolve according to the elements they manufacture

Stars are giant factories that produce most of the elements in the Universe – including the elements in us, and in the Earth’s metal deposits. But what stars produce changes over time.

Two new papers published in MNRAS shed light on how the youngest generation of stars will eventually stop contributing metals back to the universe.

The authors are all members of ASTRO 3D, the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions. They are based at Monash University, the Australian National University (ANU), and the Space Telescope Science Institute.

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Closing in on the first light in the Universe

Research using new antennas in the Australian hinterland has reduced background noise and brought us closer to finding a 13-billion-year-old signal

The early Universe was dark, filled with a hot soup of opaque particles. These condensed to form neutral hydrogen which coalesced to form the first stars in what astronomers call the Epoch of Reionisation (EoR).

“Finding the weak signal of this first light will help us understand how the early stars and galaxies formed,” says Dr Christene Lynch from ASTRO 3D, the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions.

Dr Lynch is first author on a paper published in Publications of the Astronomical Society of Australia. She and her colleagues from Curtin University and the International Centre for Radio Astronomy Research have reduced the background noise in their observations allowing them to home in on the elusive signal.

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Galaxies pump out contaminated exhausts

Research reveals how star-making pollutes the cosmos

Animation available, astronomers available in Australia and UK for interview

Galaxies pollute the environment they exist in, researchers have found.

A team of astronomers led by Alex Cameron and Deanne Fisher from the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) used a new imaging system on at the WM Keck Observatory in Hawaii to confirm that what flows into a galaxy is a lot cleaner than what flows out.

The research is published today in The Astrophysical Journal.

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New type of massive explosion explains mystery star

‘Magneto-rotational hypernova’ soon after the Big Bang fuelled high levels of uranium, zinc in ancient stellar oddity

A massive explosion from a previously unknown source – 10 times more energetic than a supernova – could be the answer to a 13-billion-year-old Milky Way mystery.

Astronomers led by David Yong, Gary Da Costa and Chiaki Kobayashi from Australia’s ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D) based at the Australian National University (ANU) have potentially discovered the first evidence of the destruction of a collapsed rapidly spinning star – a phenomenon they describe as a “magneto-rotational hypernova”.

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Bend it like Einstein: Astronomers turn galaxies into magnifiers

New technique helps NASA’s James Webb Space Telescope

Astronomers have turned a cluster of galaxies into a gargantuan magnifying lens, using it to study another galaxy, 10.7 billion light years away, in unprecedented detail.

Taking advantage of a phenomenon known as “gravitational lensing”, the team of scientists, led by NASA Goddard Space Flight Centre scientist Dr Soniya Sharma, identified star forming regions in the distant and ancient galaxy.

The research was funded by Australia’s ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D), and will be of direct benefit to NASA’s next orbiting observer.

Without the use of the massive magnifying effect, the galaxy, dubbed cswa128, would be a tiny blur to even the most powerful telescopes on Earth. With it, the astronomers can see stars being formed just three billion years after the Big Bang.

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Milky Way not unusual, astronomers find

Detailed cross-section of another galaxy reveals surprising similarities to our home

The first detailed cross-section of a galaxy broadly similar to the Milky Way, published today, reveals that our galaxy evolved gradually, instead of being the result of a violent mash-up. The finding throws the origin story of our home into doubt.

The galaxy, dubbed UGC 10738, turns out to have distinct ‘thick’ and ‘thin’ discs similar to those of the Milky Way. This suggests, contrary to previous theories, that such structures are not the result of a rare long-ago collision with a smaller galaxy. They appear to be the product of more peaceful change.

And that is a game-changer. It means that our spiral galaxy home isn’t the product of a freak accident. Instead, it is typical.

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More than 60 years to achieve gender equity?

Modelling shows urgent need to revamp hiring and working conditions for astronomers

It will take until at least 2080 before women make up just one-third of Australia’s professional astronomers, an analysis published today in the journal Nature Astronomy reveals.

“Astronomers have been leaders in gender equity initiatives, but our programs are not working fast enough,” says Professor Lisa Kewley, director of the ARC Centre of Excellence for All-Sky Astrophysics in 3 Dimensions (ASTRO 3D).

Professor Lisa Kewley.
Credit: ASTRO 3D

Kewley is also an ARC Laureate Fellow at the Australian National University’s Research School for Astronomy and Astrophysics. She developed workforce forward modelling that can predict the fraction of women at all levels in astronomy from 2021 to 2060, given different initiatives in hiring or retention. The models show that Australia’s university leadership need to adopt 50:50 or affirmative action hiring and introduce exit surveys and retention initiatives.

“With these initiatives we can reach one-third women in 11 years, growing to 50 per cent in 25,” she said.

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At cosmic noon, puffy galaxies make stars for longer

Galaxies with extended disks maintain productivity, research reveals

Massive galaxies with extra-large extended “puffy” disks produced stars for longer than their more compact cousins, new modelling reveals.

In a paper published in the Astrophysical Journal, researchers led by Dr Anshu Gupta and Associate Professor Kim-Vy Tran from Australia’s ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D), show that the sheer size of a galaxy influences when it stops making new stars. 

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The secrets of 3000 galaxies laid bare

Completion of Australian-led astronomy project sheds light on the evolution of the Universe

The complex mechanics determining how galaxies spin, grow, cluster and die have been revealed following the release of all the data gathered during a massive seven-year Australian-led astronomy research project.

The scientists observed 13 galaxies at a time, building to a total of 3068, using a custom-built instrument called the Sydney-AAO Multi-Object Integral-Field Spectrograph (SAMI), connected to the 4-metre Anglo-Australian Telescope (AAT) at Siding Spring Observatory in New South Wales. The telescope is operated by the Australian National University.

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