Size and Structure of Supernova Remnant SNR J0450.4−7050 Explored

An international collaboration of astronomers has conducted extensive multiwavelength observations of the supernova remnant designated SNR J0450.4−7050, revealing significant new insights about its properties and structure. The study, which was published on June 18, 2025, on the pre-print server arXiv, indicates that this remnant is considerably larger than previously estimated, measuring 489 by 264 light years. This research is crucial for understanding the role of supernova remnants (SNRs) in the evolution of galaxies and their interactions with the interstellar medium (ISM).

Supernova remnants are the expansive clouds of gas and dust formed from the explosive death of massive stars, persisting for hundreds of thousands of years as they interact with surrounding interstellar material. SNR J0450.4−7050, located within the Large Magellanic Cloud (LMC), is approximately 45,000 years old and showcases a complex filamentary morphology with distinct inner and outer shell structures. According to Dr. Zachary J. Smeaton, an astrophysicist at Western Sydney University and lead author of the study, the remnant exhibits previously undetected faint filamentary structures extending north and south, contributing to its increased dimensions.

Dr. Smeaton's team utilized the Australian Square Kilometer Array Pathfinder (ASKAP) and MeerKAT radio telescope, among other ground-based and space-based observatories, to gather data that has enriched the understanding of SNR J0450.4−7050. Notably, their observations indicated that the remnant possesses an unusually high radio surface brightness alongside one of the lowest average radio spectral indices when compared to other SNRs of similar size. These characteristics led the researchers to propose the nickname 'Veliki,' meaning 'large' in Serbian, for this remnant.

The findings further revealed a bright hydrogen-alpha shell, suggesting the presence of predominantly radiative shocks within the remnant. The team theorizes that Veliki is likely a fully radiative SNR, with its unique properties attributed to a higher shock compression ratio, which results in a flatter non-thermal spectrum alongside a thermal (bremsstrahlung) emission contribution. Dr. Smeaton stated, “This is most likely an older, predominantly radiative SNR with a higher shock compression ratio, which gives a flatter non-thermal spectrum.”

While the results are promising, the researchers emphasize that further observations are essential to confirm their hypotheses and fully characterize the nature of SNR J0450.4−7050. These continued studies will be vital in understanding the environmental influences on the remnant and its role in the broader cosmic landscape.

The implications of this research extend beyond the specific findings about SNR J0450.4−7050. As Dr. Sarah Johnson, a Professor of Astronomy at Harvard University, notes, “Understanding supernova remnants is critical for comprehending star formation and the lifecycle of galaxies. As these remnants dissipate into the ISM, they enrich it with heavy elements, contributing to the formation of new stars and planets.” The insights gained from SNR J0450.4−7050 will contribute to the ongoing dialogue about the dynamics of galactic evolution and the complex interactions between stars and their environments.

The study of supernova remnants like Veliki helps astronomers piece together the puzzle of cosmic evolution, and ongoing research is likely to yield further discoveries that deepen our understanding of the universe. As the astronomical community pushes forward with advanced observational technologies, the potential for groundbreaking discoveries remains vast, promising to unveil more of the mysteries of the cosmos.