Astronomers Identify Twenty Ultraviolet-Emitting Supernova Remnants in the Andromeda Galaxy

Utilizing the AstroSat satellite, astronomers from the University of Calgary, Canada, have identified twenty supernova remnants (SNRs) in the Andromeda Galaxy that exhibit diffuse ultraviolet emission. The finding, presented in a research paper released on January 25 on the arXiv preprint server, can help us better comprehend the beginning and properties of ultraviolet emission in SNRs.

SNRs are diffuse, expanding frameworks resulting from a supernova explosion. They include ejected product expanding from the explosion and other interstellar product that has been swept up by the passage of the shockwave from the exploded star.

Studies of supernova remnants

Research studies of supernova remnants are essential for astronomers, as they play an essential function in the advancement of galaxies, dispersing the heavy elements made in the supernova explosion and offering the energy required for heating up the interstellar medium. SNRs are also presumed to be responsible for galactic cosmic rays’ acceleration.

Although numerous extragalactic SNRs have been spotted to date, the ones showcasing ultraviolet (UV) emission are hard to find, mainly because of the solid interstellar termination for our galaxy in the UV. What is noteworthy, in spite of the recent progress in UV-based SNR research study, is that there doesn’t yet exist a catalog of extragalactic UV-emitting SNRs.

That is why a group of astronomers conducted by Denis Leahy chose to perform a search for UV-emitting SNRs in the nearby Andromeda Galaxy (also called as Messier 31, or M31), intending to generate the first catalog of such things in another galaxy. They employed AstroSat’s Ultraviolet Imaging Telescope (UVIT) for this objective.

“UV pictures of M31 were acquired by the Ultraviolet Imaging Telescope on the AstroSat satellite, and also the list of SNRs was obtained from X-ray, optical, and also radio catalogs of SNRs in M31. We used the UVIT pictures to find SNRs with diffuse emission, omitting those also contaminated with stellar emission,” the scientists wrote in the paper.

Research Progress

The team at first chose 177 SNRs to investigate whether or not they showcase diffuse ultraviolet emission. Out of the entire sample, 20 supernova residues ended up being UV emitters. The identified sources exhibit diffuse emission that is not connected with stars, although the strength of the diffuse emission varies.

The astronomers contrasted the band luminosities of these twenty SNRs to the band luminosities of 7 formerly known UV-emitting SNRs in the Milky Way, Big Magellanic Cloud (LMC), and Small Magellanic Cloud (SMC). In outcome, they discovered similar spectral shapes in between the known SNRs and also the SNRs in the Andromeda Galaxy. The finding recommends that the UV emission from the supernova remnants reported in the paper is dominated by line emission, which this emission is connected with the SNRs.

The research study’s authors suggest spectroscopic observations to validate the line nature of the UV emission from the recently determined SNRs. Nevertheless, they noted that it will be challenging to carry out spectroscopy for the typically crowded areas in the Andromeda Galaxy where these SNRs are located.

Read the original article on PHYS.

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