Astronomers have uncovered 307 new supernova remnants (SNRs), including seven rare oxygen-rich remnants, using a groundbreaking detection method. The findings, published on September 10 in a research paper on the preprint server *arXiv*, could significantly deepen our understanding of supernova explosions and their remnants.
Supernova remnants are the expanding debris fields left after a supernova, a powerful stellar explosion. These structures contain both the material ejected during the explosion and the surrounding interstellar matter swept up by the resulting shockwave. While supernova remnants are not uncommon, remnants rich in oxygen are exceedingly rare, with only eight previously discovered in our galaxy and the nearby Magellanic Clouds.
Now, a team led by Timo Kravtsov of the European Southern Observatory (ESO) in Chile has detected hundreds of new SNRs, including seven oxygen-rich ones, by using the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT). This new method, which takes advantage of MUSE’s ability to analyze visible-light emission lines in unprecedented detail, enabled astronomers to detect the distinct signatures of supernova remnants across distant galaxies.
“We present a new method to detect SNRs exploiting the capabilities of modern visible-light integral-field units based on the shapes of the SNR emission lines,” the researchers wrote in their paper.
Rare Oxygen-Rich Supernova Remnants
The newly detected SNRs were found as part of the PHANGS-MUSE survey, which is part of the Physics at High Angular Resolution in Nearby Galaxies (PHANGS) project. Of the 307 remnants identified, 35 exhibited oxygen emission. Seven of these were confirmed to be oxygen-rich, showing unusually strong and broad oxygen emission lines.
Oxygen-rich supernova remnants are of particular interest because they help astronomers understand certain types of supernovae, but their rarity has made them difficult to study. The latest discoveries, therefore, could shed new light on their formation and characteristics.
A Link to Ultra-Luminous X-Ray Sources?
In addition to detecting oxygen-rich SNRs, the research team noted that most of the remnants they found have counterparts in X-ray data. These X-ray sources have luminosities ranging from 10 to 100 undecillion erg/s, placing them near the threshold of ultra-luminous X-ray (ULX) sources. ULXs are extremely bright and may be powered by neutron stars or black holes, making this discovery an important clue in understanding the nature of the remnants and their origins.
Despite the similarities between the oxygen-rich remnants and old supernovae or young SNRs, the researchers found no evidence of known supernovae at the locations of the newly detected SNRs.
The study, while revealing a wealth of new information, also underscored the rarity of oxygen-rich supernova remnants. The research team hopes to apply their novel detection method to other nearby galaxies, where they anticipate discovering more of these elusive objects.
Nowakowski, Tomasz. “Astronomers Detect Hundreds of Supernova Remnants Using Novel Method.” Phys.org, Phys.org, 18 Sept. 2024, phys.org/news/2024-09-astronomers-hundreds-supernova-remnants-method.html. Accessed 19 Sept. 2024.
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