Discovery of a New Supernova Remnant by Astronomers

A group of astronomers, including those from Curtin University in Australia, have discovered a new supernova remnant (SNR) named G321.3-3.9. Located approximately 3,300 light years away, the SNR is estimated to be a few thousand years old and has an elliptical shape. SNRs are the remains of a supernova explosion, consisting of ejected material and interstellar material that has been swept up by the shockwave from the exploded star.

The study of SNRs is critical for astronomers because they are essential to the evolution of galaxies. They disperse heavy elements created during the supernova explosion and provide the energy required to heat the interstellar medium. SNRs are also believed to be responsible for the acceleration of galactic cosmic rays.

The SNR G321.3-3.9 was initially identified as a potential SNR in 1997. It was noted for its elliptical, nearly complete shell and a size of 109×64 arcmin². The peak flux was measured to be 10 mJy/beam, and the total integrated flux density was found to be greater than 0.37 Jy. The recent confirmation of its SNR status came after the analysis of radio and X-ray data from different surveys and the Spektr-RG spacecraft.

The study also revealed that G321.3-3.9 showcases an extended structure at low X-ray energies surrounded by a radio shell, with no diffuse emission in the infrared. The spectral index of the source, measured at -0.8, is in line with non-thermal synchrotron emission, a characteristic of a shell-type SNR.

The researchers estimate that G321.3-3.9 is located between 2,300 and 3,300 light years away, with a diameter of about 62–97 light years and an age in the range of 1,700–4,000 years. This estimated age is surprisingly young considering the shell shape and low brightness at radio frequencies. The team also noted uncertainties in these findings, due to the limited photon statistics in X-rays and the lack of correlation between the shell and a known pulsar.

To further their research, the team plans to conduct PARKES follow-up observations inside the remnant shell in the radio band to search for a possible pulsar association. If successful, this would facilitate the calculation of the dispersion measure, and therefore the age and distance of G321.3-3.9, along with its expansion velocity.

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