| 31st of August 2023 |
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| ASKAP discovery of candidate supernova remnants |
| by Ball et al. |
|
Ball et al. have used data from the pilot observations of the
EMU/POSSUM surveys to study the "missing supernova remnant (SNR)
problem" -- the discrepancy between the number of Galactic SNRs that
have been observed and the number that are estimated to exist.
The Evolutionary Map of the Universe (EMU) and the Polarization Sky Survey
of the Universe’s Magnetism (POSSUM) surveys are being
conducted with ASKAP. In a pilot survey field containing the plane of our Galaxy,
the team find 7 known SNRs and 21 SNR
candidates, of which 13 have not been previously studied.
These are the first discoveries of Galactic SNR candidates with EMU/POSSUM and,
if confirmed, will increase the SNR density in this field by a
factor of 4. By comparing our SNR candidates to the known Galactic SNR
population, it is shown that many of these sources would have been
missed in previous surveys due to their small angular size and/or low
surface brightness. The results of this paper
demonstrate the potential of the full EMU/POSSUM surveys to uncover
more of the missing Galactic SNR population.
The images above show comparisons of the radio and mid-infrared (MIR) emission from an ionized HII region (top row) and an SNR (bottom row). From left to right in each row, the images are the radio image (from ASKAP), MIR image (from WISE), and a combined image with radio in red and MIR in blue. The absence of an MIR counterpart in the bottom row is supporting evidence for this object being a SNR rather than an HII region. |