Astronomers study the supernova remnant of Meerkat Urania

Astronomers from the National Radio Astronomy Observatory (NRAO) and other centers used the MeerKAT radio telescope to study 36 supernova remnants. The results of the monitoring campaign, published on November 20 on the arXiv server, give us important insight into the properties of these organisms.

Supernova remnants (SNRs) expand and spread out structures resulting from the supernova explosion. They consist of matter ejected from the dying star as a result of this explosion and other interstellar material that is compressed and displaced by the shock wave generated by the star’s explosion. The study of supernova remnants is very important to astronomers because they play a key role in the evolution of galaxies, scattering heavy elements from the explosion within the galaxy and providing the energy needed to heat the interstellar medium. Supernovas are also believed to be responsible for accelerating galactic cosmic rays.

Recently, a team of astronomers led by NRAO’s William Cotton selected 36 poorly studied galactic supernova remnants for observations using the MeerKAT antenna array. The goal of the research was simple: they wanted to learn more about the properties of these specific SNRs.

– We present complete L-band (856-1.712 MHz) MeerKAT observations of 36 supernova remnants at high galactic latitudes. – the scientists wrote in their article.

Interestingly, these observations showed that two of the 36 observed SNRs were not supernova remnants at all. The object, called G30.7-2.0, and initially classified as a relic, has now been shown to be a structure consisting of three relatively bright background radio sources that appear to form an arc. The second object, G15.1-1.6, appears to be a region of ionized interstellar atomic hydrogen (HII).

The images also show that at least half of the SNR tested had bulges or bumps. Most indicate that something penetrates the outer edge of the remains. Astronomers confirm that this discovery was only possible thanks to the exceptional sensitivity and high quality of images captured in the so-called intense broadcast provided by the MeerKAT network. Most of the observed bulges have very low radio brightness, which this network handles very well.

The research conducted allowed the team to examine the magnetic fields present in the sample’s remains. For example, the magnetic field within remnant G327.6+14.6 is found to have a largely radial component, while SNR G4.8+6.2 in turn shows a largely tangential magnetic field, except in the explosion regions where it is. Also radial.

The astronomers also found that many of the supernova remnants they studied showed a double-sided or barrel-shaped structure. Such structures are very common in mature SNRs and indicate their expansion within an almost uniform medium with a relatively uniform magnetic field.

MeerKAT is an interference network of 64 antennas with a diameter of 13.5 meters in the Northern Cape region of Africa. This interferometer will be the largest and most sensitive radio telescope in this region until construction of the SKA network is completed (Square kilometer matrix), which is expected to be completed no later than 2024. The MeerKAT telescope is used for research into cosmic magnetic fields, the evolution of galaxies, the large-scale structure of the universe, dark matter, and the nature of transient radio sources in the sky. It saw its “first light” in July 2016.

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Source: Phys.org

Prepared by: Elizabieta Kolegoska

Pictured: MeerKAT image of the so-called total power of one of the studied SNRs, G4.2-3.5, at a frequency of 1.335 MHz in Galactic coordinates. Source: arXiv (2023)