A study from the University of Queensland has tracked dwarf galaxies to understand if the evolution of the Milky Way is similar to other parts of the Universe.
In collaboration with the Australian National University’s Research School of Astronomy and Astrophysics, among others, the Delegate survey found that a cosmic dance could be the future of the Milky Way as it tracks a course to collide with neighbouring dwarf and spiral galaxies.
“The Milky Way will merge with Andromeda and their respective smaller dwarf galaxies in the next 2.5 billion years, and while there has been a lot of research into what’s happening in our Local Group, we don’t know how typical it is,” explained Dr Sarah Sweet from Queensland’s School of Mathematics and Physics.
Spiral and dwarf galaxies combine to form satellite structures
The team studied two similar spiral galaxies that are about 3 billion years ahead of the Milky Way and Andromeda in merging.
The research showed that these galaxies – NGC5713 and NGC5719 – combine as if they were dancing with the closely located dwarf satellites rotating around them.
Without these mergers, the galaxies might remain in a randomly distributed cloud, not arranged in beautiful, coherent planes like those around the Milky Way and Andromeda.
Refining models of galaxy evolution
“This may offer our clearest look yet at how structures like the Milky Way’s satellite system form, and how they will evolve,” Sweet said.
“Understanding our galaxy’s likely future helps us refine models of galaxy evolution, dark matter, and cosmic structure and beyond that, it gives us perspective.”
The research shows that the Milky Way is part of a much larger cosmic story, one that unfolds over billions of years, involving dances of dwarf galaxies and the shaping of the Universe itself.
Comparisons of the Milky Way and other twin-like systems
Several papers will be published as part of the Delegate survey to confirm the galaxy evolution findings.
Research paper lead, ANU Professor Helmut Jerjen, said the researchers were comparing our local galaxy group to other twin-like systems.
Professor Jerjen commented: “We will test whether the Milky Way and Andromeda Local Group is a poster child or a cosmic outlier. Until we know this, our ability to generalise findings from the Local Group of galaxies to understand galaxy evolution in a broader cosmological context is hampered.”
For example, there is persisting tension between local galaxy group observations and the world’s most sophisticated cosmological computer simulations, such as the observed placement of dwarfs preferentially in satellite planes around their hosts.
New simulations to uncover the future of our galaxy
The new observations from the Delegate survey suggest that current simulations of spiral and dwarf galaxies need to be overhauled.
Professor Jerjen concluded: Will the Milky Way begin its own dance with Andromeda, with the smaller dwarf galaxies rotating around them? That’s what we want to find out.”