Wednesday, September 28, 2022

Mysterious ring in space may be the first known intergalactic supernova

The universe is not a chaotic free-for-all. Most of the stars are bound in galaxies, separated by vast, almost unimaginable distances.

The space between galaxies – the intergalactic space – is sparsely populated, but not completely empty; There, too, sometimes lonely stars can be found.

For the first time, astronomers think they have found evidence of the death of one of these lone rogue stars. Not far from the Large Magellanic Cloud, a satellite galaxy orbiting with the Milky Way, a mysterious and remarkably neat circle emitting radio waves has been found hanging in space, and is called J0624-6948. Is.

If this sounds familiar, there’s a reason for it. Recently, astronomers have been intrigued by a number of mysterious, radio-emitting space circles, named strange radio circles, or ORCs.

The similarity was not lost on astronomer Miroslav Filipovic of the University of Western Sydney in Australia.

“When we originally discovered this almost perfectly spherical radio object we thought it was yet another ORC,” he says. “But after our additional observations, it became clear that this object was more likely to be something else.”

The ORCs were first discovered using the Australian Square Kilometer Array Pathfinder (ASKAP) in Australia, one of the world’s most powerful radio telescopes. These objects seemed massive and distant, with many defining features, not the least of which is a galaxy at the dead center.

Scientists now think that the ORC is the result of an energetic process in those central galaxies, although the exact nature of that process is unknown.

In fact, it is possible that the orcs are indeed circular. The reason they appear as rings is perspective; Around the edges, the density of emissions is higher along our line of sight.

space supernova locationLocation of J0624-6948. (Filipovic et al., MNRAS, 2022)

Yet there are some important differences between J0624-6948 and ORC. The lack of a clear central galaxy in J0624-6948 is a big one, but not conclusive in itself. The spectral index of radio emission is more flat than that of ORCs, and J0624–6948 has an apparent size variation, that too—larger than other ORCs.

Filipovic and his team considered several possibilities that could result in an object that resembled their observations. These include a very large ORC, as well as a super-flare that originates in a star near the galactic center, or jets from a distant active supermassive black hole.

Finally, one scenario emerged as the most consistent with the observed event.

“The most plausible explanation is that the object is a space supernova remnant caused by an exploded star that resided on the outskirts of the Large Magellanic Cloud that underwent a single-degenerate Type Ia supernova that involved the explosion of two stars orbiting each other. It is,” Filipovic explains.

“What we have potentially discovered is a unique relic [a] Supernova that has expanded into a rarefied, intergalactic environment – ​​an environment we did not expect to find in such an object. Our estimate points to an age of about 2,200 to 7,100 years.”

While supernova remnants are not so beautifully circular, this would not be phenomenal. Some similar examples have been documented, such as the stunning eye-shaped object SN 1987A in the Large Magellanic Cloud.

If scientists are correct, J0624-6948 will be the first space supernova remnant ever identified – a bubble-like ball of ejecta expanding outward. According to the team’s measurements, an association with the Large Magellanic Cloud would make J0624-6948 about 155 light-years across.

Follow-up comments may help resolve uncertainties. In addition, more observations with instruments such as ASKAP and its South African counterpart MeerKAT could help identify more specific radio circles in the sky.

Finding out more will give us a more complete picture of their range and diversity, which gives us a better chance of finding out what they are.

“These new radio telescopes can pick up a range of spherical objects,” Filipovic says. “Because of the combined effects of high sensitivity, good spatial sampling and wide area coverage, they are enriching our understanding of the universe.”

research has been published in Monthly Notices of the Royal Astronomical Society,

Nation World News Desk
Nation World News Desk
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