Astronomers have made the most detailed map of the star formation history of the Large Magellanic Cloud to date. This history of one of our closest galactic neighbours could help us understand the history of our local region of space, as well as improving models of how stars and galaxies form.
The Large Magellanic Cloud and Small Magellanic Cloud are satellite galaxies of the Milky Way, meaning they are all gravitationally bound to one another. At about 163,000 light years away, the Large Magellanic Cloud one of the nearest galaxies in the cosmos, which makes it one of only a few that we can study in detail.
Alessandro Mazzi at the University of Padua in Italy and his colleagues used data from the Visible and Infrared Survey Telescope for Astronomy (VISTA) in Chile to construct their map. It covers most of the galaxy – an area about 50 per cent bigger than older maps of star formation – at higher resolutions than previous work.
The data showed that the most intense period of star formation happened between about 4 and 0.5 billion years ago, when dust and gas in the Large Magellanic Cloud turned into stars at rates of about 0.3 times the mass of the sun per year. “If you look at the map, you can clearly see when the spiral arms formed, when the central body formed, when the peaks of star formation were,” says Mazzi.
For the most part, the researchers’ conclusions matched up with previous work, although they found lower rates of star formation when the galaxy was young. This could tell us something about the formation of stars more generally, as well as about their formation in our galactic neighbourhood in particular.
“Most of the reason why we care about the Magellanic Clouds is that they are incredible grounds for understanding the processes that govern the formation of galaxies,” says Mazzi. “Moving one peak of the star formation history might constrain interactions with the galaxies and other astronomical objects.”
Because the Large Magellanic Cloud is so close, these other astronomical objects could have affected the Milky Way as well.
Journal reference: Monthly Notices of the Royal Astronomical Society, DOI: 10.1093/mnras/stab2399
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