New research has found that ultra-faint satellite galaxy systems orbiting our Milky Way could tell us about the conditions of the early Universe – and why some galaxies grew while others didn’t.
A new study involving our Department of Physics used supercomputer simulations to look at these dwarf galaxies in unprecedented resolution.
The simulations could be a major step forward in learning how the Milky Way’s neighbouring galaxies formed and evolved.
Researchers say these galaxies could also help us to investigate conditions even further away in the early Universe and understand why it looks as it does today.
In their simulations, researchers altered radiation levels in the early Universe when it was less than 500 million years old. The Universe is now 13 billion years old.
They were able to see which small dark matter haloes – areas where stars and galaxies grow – were able to form stars at all.
The researchers found that small, ultra-faint galaxies were very sensitive to changes in radiation, while more massive galaxies, like our Milky Way, weren’t really affected.
They say that for the smallest galaxies, conditions in the early Universe could decide whether they become visible galaxies or remain starless dark matter haloes.
(A) Dark matter map in our neighbourhood in the Universe. The two large densities are dark matter haloes of the Milky Way and Andromeda galaxy; (B) Zoomed-in on the dark matter map, showing a small dark matter clump approximately 700 million years after the Big Bang; (C) stars and gas in the simulated ultra-faint dwarf galaxy, hosted in the centre of the small dark matter halo in panel B. Image credit: J Sureda/A Fattahi/S Brown/S Avraham.
The research will be tested against upcoming observations, including those from the Vera C. Rubin Observatory, in Chile.
Rubin will be able to find many more of these ultra-faint dwarf galaxies around our Milky Way.
By studying our local Universe in such detail, the researchers hope this will tell us what the wider Universe looked like in its infancy.
Read the full research paper in Monthly Notices of the Royal Astronomical Society.
The research was led by Dr Shaun Brown, formerly of Durham University’s Department of Physics. Dr Azadeh Fattahi, of the Oskar Klein Centre (OKC), University of Stockholm, and a visitor to our Department of Physics, is a co-author.
The research team also included the LYRA collaboration.
Simulations were carried out on the COSMA 8 supercomputer on behalf of the DiRAC High Performance Computing Facility. COSMA 8 is hosted by Durham University and funded primarily by UK Research and Innovation, administered by the Science and Technology Facilities Council (STFC).
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Banner image: Stars and gaseous material in the simulated ultra faint dwarf galaxy. Credit: J Sureda/A Fattahi/S Brown.
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