Astronomers have captured the central region of our Milky Way in a striking new image, unveiling a complex network of filaments of cosmic gas in unprecedented detail. When Maya Petkova, an astronomer at Chalmers, saw the whole image for the first time, she was struck by the incredible level of detail in the areas between the few well-studied clouds.
"All of a sudden the Galactic Center emerged as one rich interconnected system, where each region that we study gives us a different piece of the puzzle of how this system functions", says Maya Petkova, who co-led the theory and simulation group within ACES, the research project behind the new study.
Obtained with the telescope ALMA (Atacama Large Millimeter/submillimeter Array), this rich dataset – the largest ALMA image to date – will allow astronomers to probe the lives of stars in the most extreme region of our galaxy, next to the supermassive black hole at its centre.
The region featured in the new image spans more than 650 light-years. It harbours dense clouds of gas and dust, surrounding the supermassive black hole at the centre of our galaxy. The observations provide a unique view of the cold gas – the raw material from which stars form – within the so-called Central Molecular Zone (CMZ) of our galaxy. It is the first time the cold gas across this whole region has been explored in such detail.
The dataset reveals the CMZ like never before, from gas structures dozens of light-years across all the way down to small gas clouds around individual stars. The gas that the project ACES — the ALMA CMZ Exploration Survey — specifically explores is cold molecular gas. The survey unpacks the intricate chemistry of the CMZ, detecting dozens of different molecules, from simple ones such as silicon monoxide to more complex organic ones like methanol, acetone or ethanol.
Cold molecular gas flows along filaments feeding into clumps of matter out of which stars can grow. In the outskirts of the Milky Way we know how this process happens, but within the central region the events are much more extreme.
The only galaxy centre we can study in detail
"We can’t understand the evolution of galaxies – including ours – without an understanding of how their centres form stars" says Chalmers astronomer Maya Petkova.
"We know that the molecular gas in galaxy centres is subjected to extreme conditions compared to our solar neighbourhood, but we don't fully understand how this impacts the star formation process. Our own Galactic Center is our closest example of an extreme star formation environment, and the only one that we can study in detail to help us answer these questions".
More information:
This research was presented in a series of papers presenting the ACES data, to appear in Monthly Notices of the Royal Astronomical Society. The results were also presented in a press release from European Southern Observatory: Largest image of its kind shows hidden chemistry at the heart of the Milky Way, on which the text above is based.
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. Sweden is one of ESO’s 16 member states.