By ARC Centre of Excellence for All Sky Astrophysics in 3D (ASTRO 3D) April 15, 2024New research shows galaxy age as the key consider star movement, challenging older theories that highlighted environment or mass. Credit: SciTechDaily.comAn global group led by Australian research center ASTRO 3D reports that age is the driving force in altering how stars move within galaxies.Galaxies start life with their stars turning in an orderly pattern however in some the movement of stars in more random. Until now, researchers have been unsure about what causes this– perhaps the surrounding environment or the mass of the galaxy itself.Key Findings on Galaxy AgeA new research study, released in just recently in MNRAS (Monthly Notices of the Royal Astronomical Society), has discovered that the most crucial element is neither of these things. It reveals the tendency of the stars to have random movement is driven mostly by the age of the galaxy– things simply get untidy with time.”When we did the analysis, we found that age, regularly, whichever way we slice or dice it, is always the most essential specification,” says first author Prof Scott Croom, an ASTRO 3D scientist at the University of Sydney.Environmental and Mass Factors”Once you account for age, there is basically no ecological pattern, and its comparable for mass.”If you find a young galaxy it will be rotating, whatever environment it remains in, and if you discover an old galaxy, it will have more random orbits, whether its in a dense environment or a void.”A comparison of a young (top) and old (bottom) galaxy observed as part of the SAMI Galaxy Survey. Panels on the left are routine optical images from the Subaru Telescope. In the middle are rotational velocity maps (blue coming towards us, red going away from us) from SAMI. On the right are maps measuring random velocities (redder colours for greater random velocity). Both galaxies have the same overall mass. The top galaxy has a typical age of 2 billion years, high rotation and low random motion. The bottom galaxy has an average age of 12.5 billion years, slower rotation and much bigger random motion. Credit: Hyper Suprime-Cam Subaru Strategic ProgramResearch Team and MethodologyThe research team also consisted of scientists from Macquarie University, Swinburne University of Technology, the University of Western Australia, the Australian National University, the University of New South Wales, the University of Cambridge, the University of Queensland, and Yonsei University in the Republic of Korea.The study updates our understanding from previous studies that have actually variously recommended environment or mass as more crucial aspects. But the earlier work is not always inaccurate, states second author Dr. Jesse van de Sande.Young galaxies are star-forming super-factories, while in older ones, star development ceases.”We do understand that age is impacted by environment. It will tend to shut down the star formation if a galaxy falls into a dense environment. Galaxies in denser environments are, on average, older,” Dr. van de Sande states.”The point of our analysis is that its not living in dense environments that reduces their spin, its the reality that theyre older.”The Milky Ways DynamicsOur own galaxy, the Milky Way, still has a thin star-forming disk, so is still thought about a high-spin rotational galaxy.”But when we look at the Milky Way in detail, we do see something called the Milky Way thick disk. Its not dominant, in terms of light, but it exists and those seem older stars, which may well have actually been heated from the thin disk at earlier times, or born with more rough movement in the early Universe,” Prof Croom says.Contributions of the SAMI Galaxy SurveyThe research utilized data from observations made under the SAMI Galaxy Survey. The SAMI instrument was developed in 2012 by the University of Sydney and the Anglo-Australian Observatory (now Astralis). SAMI uses the Anglo-Australian Telescope, at Siding Spring Observatory, near Coonabarabran, New South Wales. It has actually surveyed 3000 galaxies across a large variety of environments.The study allows astronomers to rule out lots of procedures when attempting to comprehend galaxy formation and so fine-tune models of how deep space has developed.Future Directions in Galaxy ResearchThe next steps will be to develop simulations of galaxy advancement with more granular detail.”One of the difficulties of getting simulations right is the high resolution you require in to forecast whats going on. Common existing simulations are based on particles which have the mass of maybe 100,000 stars and you cant solve small-scale structures in galaxy disks,” Prof. Croom says.The Hector Galaxy Survey will assist Prof Croom and his team expand this work utilizing a brand-new instrument on the Anglo-Australian Telescope.”Hector is observing 15,000 galaxies but with higher spectral resolution, allowing the age and spin of galaxies to be determined even in much lower mass galaxies and with more in-depth environmental details,” states Professor Julia Bryant, lead of the Hector Galaxy Survey, University of Sydney.Conclusion and Impact on Universal UnderstandingProfessor Emma Ryan-Weber, Director of ASTRO 3D, states, “These findings answer one of the crucial questions positioned by ASTRO 3D: how does mass and angular momentum progress in the Universe? This mindful work by the SAMI team exposes that the age of a galaxy figures out how the stars orbit. This critical piece of information contributes to a clearer big-picture view of the Universe.”Reference: “The SAMI Galaxy Survey: galaxy spin is more highly correlated with stellar population age than mass or environment” by Scott M Croom, Jesse van de Sande, Sam P Vaughan, Tomas H Rutherford, Claudia del P Lagos, Stefania Barsanti, Joss Bland-Hawthorn, Sarah Brough, Julia J Bryant, Matthew Colless, Luca Cortese, Francesco DEugenio, Amelia Fraser-McKelvie, Michael Goodwin, Nuria P F Lorente, Samuel N Richards, Andrei Ristea, Sarah M Sweet, Sukyoung K Yi and Tayyaba Zafar, 3 April 2024, Monthly Notices of the Royal Astronomical Society.DOI: 10.1093/ mnras/stae458ABOUT ASTRO 3DThe ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) is a $40m Research Centre of Excellence funded by the Australian Research Council (ARC) and 9 collaborating Australian universities– The Australian National University, The University of Sydney, The University of Melbourne, Swinburne University of Technology, The University of Western Australia, Curtin University, Macquarie University, The University of New South Wales, and Monash University.ABOUT the SAMI Galaxy SurveyThe SAMI Galaxy Survey started in March 2013, with the objective of creating a large survey of 3000 galaxies across a large series of environment. The information for the SAMI Galaxy Survey was gathered using SAMI, the Sydney-Australian-Astronomical-Observatory Multi-object Integral-Field Spectrograph. SAMI is an instrument on the 4-meter Anglo-Australian Telescope at Siding Spring Observatory. Integral-field spectroscopy (IFS) enables a distinct view of how stars and gas zoom around inside far-off galaxies since we gather dozens of spectra across the whole face of each galaxy.
Until now, researchers have actually been unpredictable about what causes this– potentially the surrounding environment or the mass of the galaxy itself.Key Findings on Galaxy AgeA new research study, released in just recently in MNRAS (Monthly Notices of the Royal Astronomical Society), has discovered that the most crucial aspect is neither of these things. It has surveyed 3000 galaxies across a large range of environments.The study allows astronomers to rule out numerous processes when attempting to understand galaxy formation and so fine-tune models of how the Universe has developed.Future Directions in Galaxy ResearchThe next steps will be to develop simulations of galaxy development with more granular information.”Hector is observing 15,000 galaxies but with greater spectral resolution, enabling the age and spin of galaxies to be determined even in much lower mass galaxies and with more detailed ecological info,” states Professor Julia Bryant, lead of the Hector Galaxy Survey, University of Sydney.Conclusion and Impact on Universal UnderstandingProfessor Emma Ryan-Weber, Director of ASTRO 3D, states, “These findings respond to one of the key questions positioned by ASTRO 3D: how does mass and angular momentum progress in the Universe?”Reference: “The SAMI Galaxy Survey: galaxy spin is more strongly correlated with excellent population age than mass or environment” by Scott M Croom, Jesse van de Sande, Sam P Vaughan, Tomas H Rutherford, Claudia del P Lagos, Stefania Barsanti, Joss Bland-Hawthorn, Sarah Brough, Julia J Bryant, Matthew Colless, Luca Cortese, Francesco DEugenio, Amelia Fraser-McKelvie, Michael Goodwin, Nuria P F Lorente, Samuel N Richards, Andrei Ristea, Sarah M Sweet, Sukyoung K Yi and Tayyaba Zafar, 3 April 2024, Monthly Notices of the Royal Astronomical Society.DOI: 10.1093/ mnras/stae458ABOUT ASTRO 3DThe ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) is a $40m Research Centre of Excellence funded by the Australian Research Council (ARC) and 9 collaborating Australian universities– The Australian National University, The University of Sydney, The University of Melbourne, Swinburne University of Technology, The University of Western Australia, Curtin University, Macquarie University, The University of New South Wales, and Monash University.ABOUT the SAMI Galaxy SurveyThe SAMI Galaxy Survey began in March 2013, with the intent of producing a big survey of 3000 galaxies throughout a large variety of environment. Integral-field spectroscopy (IFS) allows a special view of how stars and gas zoom around inside remote galaxies since we gather dozens of spectra across the whole face of each galaxy.
