The completion of the Australian guided astronomy project sheds light on the evolution of the universe.
The intricate mechanics that determine how galaxies rotate, grow, group and die were revealed after the release of all the data collected during a massive astronomy research project led by Australia for seven years.
The scientists observed 13 galaxies simultaneously and built to a total of 3068, using a custom instrument called the Sydney-AAO Multi-Object Integral-Field Spectrograph (SAMI), connected to the 4-meter Anglo-Australian telescope ( AAT)) at Siding Spring Observatory in New South Wales. The telescope is controlled by the Australian National University.
Under the supervision of the ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), the project used bundles of optical fibers to capture and analyze bands of colors, or spectra, at various points in each galaxy.
The results enabled astronomers from around the world to investigate how these galaxies interacted with each other, and how they grew, accelerated or slowed down over time.
The SAMI instrument in the Anglo Australian telescope is being prepared for action. Credit: Ángel R. López-Sánchez (AAO-MQ)
No two galaxies are alike. They have different bumps, tails, discs and rings. Some form new generations of stars, while others have not done so for billions of years. And there are powerful feedback loops in it that are fueled by supermassive black holes.
“With the SAMI survey, we can see the actual internal structures of galaxies, and the results were astonishing,” said lead author Professor Scott Croom of ASTRO 3D and the University of Sydney.
“With the large size of the SAMI survey, we can identify similarities as well as differences so that we can come closer to understanding the forces that influence the fate of galaxies during their very long lives.”
The survey, which began in 2013, has already formed the basis of dozens of astronomy articles, with a few more being prepared. Today (February 2, 2021) a paper was published today (February 2, 2021) containing the final release of data – for the first time the details of 888 galaxies within galaxies. Monthly notices from the Royal Astronomical Society.
“The nature of galaxies depends on how massive they are and their environment,” Professor Croom said.
‘They can be lonely, for example, in the gaps, or in the dense heart of galactic clusters or anywhere in between pressure. The SAMI survey shows how the internal structure of galaxies simultaneously relates to their mass and environment, so that we can understand how these things affect each other. ”
Research resulting from the survey has already shown several unexpected outcomes.
One group of astronomers has shown that the direction of rotation of a galaxy depends on the other galaxies around it, and changes depending on the size of the galaxy. Another group has shown that the amount of rotation that a galaxy has is mainly determined by its mass, with little influence on the surrounding environment. A third looked at galaxies that were making stars, and found that the process began for many only a billion years after they drifted away from clusters in the dense downtown regions.
A / Prof Julia Bryant from the University of Sydney in the SAMI instrument at the top of the Anglo Australian Telescope. Credit: Scott Croom / University of Sydney
“The SAMI survey was set up to help us answer some very broad questions at the highest level about the evolution of the galaxy,” said co-author Dr Matt Owers of Macquarie University in Australia.
‘The detailed information we have gathered will help us understand fundamental questions, such as: Why do galaxies look different depending on where they live in the universe? Which processes prevent galaxies from forming new stars, and conversely, which processes drive the formation of new stars? Why do the stars in some galaxies move in a highly ordered rotating disk, while their orbits are randomly aligned in other galaxies? “
Professor Croom added: “The survey has now been completed, but by making it all public, we hope the data will last for many more years.”
Co-author, Associate Professor Julia Bryant of ASTRO 3D and the University of Sydney, said: ‘The next steps in this research will use a new Australian tool – which we named Hector – starting in 2021, which details will increase and the number of galaxies that can be observed. ”
When Hector is fully installed, it will examine 15,000 galaxies.
Reference: “The SAMI Galaxy Survey: the third and final data release” by Scott M Croom, Matt S Owers, Nicholas Scott, Henry Poetrodjojo, Brent Groves, Jesse van de Sande, Tania M Barone, Luca Cortese, Francesco D’Eugenio, Joss Bland-Hawthorn, Julia Bryant, Sree Oh, Sarah Brough, James Agostino, Sarah Casura, Barbara Catinella, Matthew Colless, Gerald Cecil, Roger L Davies, Michael J Drinkwater, Simon P Driver, Ignacio Ferreras, Caroline Foster, Amelia Fraser- McKelvie, Jon Lawrence, Sarah K Leslie, Jochen Liske, Ángel R López-Sánchez, Nuria PF Lorente, Rebecca McElroy, Anne M Medling, Danail Obreschkow, Samuel N Richards, Rob Sharp, Sarah M Sweet, Dan S Taranu, Edward N Taylor , Edoardo Tescari, Adam D Thomas, James Tocknell and Sam P Vaughan, February 1, 2021, Monthly notices from the Royal Astronomical Society.
DOI: 10.1093 / mnras / stab229
The final publication paper has 41 authors from Australia, Belgium, the USA, Germany, Britain, Spain and the Netherlands.
The complete data set is available online via the Australian Astronomical Optics (AAO) Data Central.