Cosmic models predict that supernova remnants are much more common than they actually are. Now, new images from sensitive radio telescopes reveal the missing wreckage lurking in plain sight.
When many stars reach the end of their lives, they explode as supernovae, leaving behind clouds of expanding matter. But the story is not so simple. Based on the age and density of the Milky Way, astronomers have calculated that we should see up to five times more supernova remnants than have ever been discovered. That raises the obvious question – where are they all?
After all, supernova remnants are there all the time, invisible to most instruments. To find them, the astronomer combined observations from his two radio telescopes in Australia, the famous Parkes Dish and his ASKAP. Each has different advantages. Parkes can capture a wider range of data, but ASKAP’s snaps have higher resolution and provide much more detail.
Combining their powers, the two radio telescopes have mapped an area of about 1% of the Milky Way’s galactic plane. Seven supernova remnants are typically seen in this region, but the new images reveal more than 20 new supernova remnants. The bright blobs in the image are supernova remnants, and the green blotches represent hydrogen gas between them, which could drive new star birth.
CSIRO, R. Kothes (NRC), E. Carretti (INAF), EMU and POSSUM Team
The combined power of each radio telescope brought the ghostly gas cloud into focus. In Parkes’ image, this area he sees as little more than a greenish fog with two red glowing orbs. The ASKAP image shows details of the wreckage, but misses the big picture behind how they are connected. But when the images are put together, they reveal an invisible stellar graveyard.
And this is just the beginning. Both telescopes are currently in use for a long-term project to map much of the Milky Way, capturing an area about 100 times larger than this image with the same level of detail. This should reveal as many as 1,500 new supernova remnants, the team says.
Source: CSIRO, The Conversation
