Astronomers used the Dark Energy Camera (DECam) in Chile as a kind of electronic nanny, observing a region of nearby space absolutely filled with stellar nurseries.
The Large and Small Magellanic Clouds are the only two dwarf galaxies visible to the naked eye from Earth, and thankfully they are also home to some of the most active star forming regions in our Local Group of galaxies.
This isn’t the first time we’ve tried to look inside and see what these newborns are doing, but it’s the most insightful one yet.
The MAgellanic stellar history survey (SMASH) required 50 nights of observation to map in great detail an area 2,400 times the size of the full moon. The results are breathtaking.
Images of the most complex regions of the Magellanic Clouds have now provided about 4 billion measurements of 360 million objects that scientists hope to turn into a “home movie” for this celestial family – potentially going back 13 billion years.
“These satellite galaxies have been studied for decades, but SMASH is used to map their structure to the fullest extent and helps solve the mystery of their formation,” explains astronomer David Nidever of Montana State University.
As the gas in these clouds collapses, new stars are still being born rapidly, and data from SMASH suggest that this spike in activity was initially triggered by the collision of large and small Magellanic galaxies long ago.
Now the two are still circling each other. Astronomers believe that one day, far in the future, both will be swallowed up by our Milky Way.
Although the Magellanic Clouds are close and rather small, detailed mapping still requires deep and efficient imaging. DECam – a massive camera built to observe millions of galaxies in order to understand how dark energy separates them – is the perfect tool for keeping a close eye on these young stellar neighbors.
Using data from DECam at the Cerro Tololo Inter-American Observatory in Chile, astronomers probed straight to the center of the Magellanic Clouds, where there are many nurseries.
“In addition to creating amazing images, this data allows us to look back and reconstruct the way the Magellanic Clouds formed their stars over time,” says astronomer Knut Olsen of the National Science Foundation in the United States.
“With these ‘movies’ about star formation, we can try to understand how and why these galaxies evolved.”
The article was accepted by The Astronomical Journal and is available on arXiv.