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In an article for The Conversation,
Andrew Hopkins describes work
that combines data from the ASKAP radio telescope and the Parkes radio telescope, Murriyang,
to answer the question: where are all the supernova remnants?
A supernova remnant is an expanding cloud of gas and dust marking the
last phase in the life of a star, after it has exploded as a
supernova. But the number of supernova remnants we have detected so
far with radio telescopes is too low. Models predict five times as
many, so where are the missing ones?
The image above shows the ASKAP (left) and Parkes (right) views of
about 1% of the plane of our Galaxy, the Milky Way. In the
combination of these images, more than 20 new possible supernova
remnants were discovered where only seven were previously known. The
resolution of radio-astronomy images depends on the size of the
telescope. The Parkes Dish, Murriyang, is 64m in diameter, but the 36
ASKAP dishes are spread over 6km, proving almost 100 times better
angular resolution. However, ASKAP's fine resolution but comes at the
expense of missing radio emission on the largest scales, which are
captured by the Parkes Dish.
By combining the information from both Parkes and ASKAP, each fills in
the gaps of the other to give us the best fidelity image of this
region of our Milky Way galaxy. This combination reveals the radio
emission on all scales to help uncover the missing supernova remnants.
Astronomers estimate there may be up to 1,500 or more new supernova
remnants yet to discover. Solving the puzzle of these missing remnants
will open new windows into the history of our Milky Way.
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