Astronomers Detect Hundreds of Supernova Remnants Using New Method

Using a new method that exploits the capabilities of the Multi Unit Spectroscopic Explorer (MUSE), astronomers have detected 307 new supernova remnants, including seven rare oxygen-rich ones. The discovery was presented in a research paper published September 10 on the preprint server arXiv.

Supernova remnants (SNRs) are diffuse, expanding structures resulting from a supernova explosion. They contain expanding ejected material from the explosion and other interstellar material that was carried away by the passage of the shock wave from the exploded star.

Some supernova remnants emit strong oxygen emission in visible light, and are therefore known as oxygen-rich SNRs. However, oxygen-rich SNRs are rarely found, as to date only eight such objects have been identified in our galaxy and the Magellanic Clouds. Furthermore, the nature of these SNRs and their connection to specific supernovae (SNe) is not yet well understood.

A team of astronomers led by Timo Kravtsov of the European Southern Observatory (ESO) in Chile recently reported new findings that could advance our knowledge of oxygen-rich supernova remnants. Using a new signal-to-noise detection method, they managed to discover hundreds of new remnants with MUSE on ESO’s Very Large Telescope (VLT), including those showing oxygen emission.

“We present a new method to detect SNRs by exploiting the capabilities of modern visible light integral field units based on the shapes of SNR emission lines,” the researchers explained.

In their results, the team identified 307 supernova remnants in galaxies from the PHANGS-MUSE survey, part of the PHANGS (Physics at High Angular Resolution in Nearby Galaxies) project. Among this sample, they detected oxygen emission in 35 SNRs and, upon closer inspection, seven of them turned out to be oxygen-rich, as they exhibited unusually strong and broad oxygen lines.

According to the study, most of the detected SNRs have X-ray counterparts, whose luminosity lies in the range of 10 to 100 undecillion erg/s. The astronomers noted that this lies near the limit of ultraluminous X-ray sources (ULX) and around the Eddington limit of neutron star mass objects.

Additionally, due to the similarity between the discovered oxygen-rich SNRs and old/young supernovae, the researchers conducted a search for known SNe at the locations of the SNRs in the sample. However, no such SNe was found.

Summarizing the results, the study authors emphasized that their study further underscores the rarity of oxygen-rich supernova remnants. They plan to extend their new method to other nearby galaxies, in the hopes of detecting more oxygen-rich SNRs, which could shed more light on the origin and properties of these remnants.

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