The brightest pulsar detected thanks to “sunglasses”

A pulsarit’s a bit like a lighthouse that guides the astronomers in the immensity ofUniverse. A star pulsating that emits waves radio at such a regular rate that researchers first believed in…signals sent by extraterrestrial civilizations. Astronomers now know that pulsar are none other than neutron stars, what’s left of massive, incredibly dense stars that spin very quickly. In just one second. Even less.

The first pulsar was observed in 1967 near Cambridge (United Kingdom). Since then, more than 3,000 other pulsars have been detected. Most in our Galaxy. But about thirty all the same, in our closest neighbour, the Large Magellanic Cloud. And today, it is thanks to a new technique that astronomers of the Commonwealth Scientific and Industrial Research Organization (Csiro) have just made an astonishing discovery there. This bright spot that researchers took until then for a distant galaxy would in fact be just one more pulsar in the heart of the Large Magellanic Cloud. And not just any pulsar. The one they named PSR J0523-7125 would be the brightest pulsar ever observed outside the Milky Way. Perhaps even the most luminous pulsar of all!

To understand how such an object could have passed under the radar so far, it is necessary to know that classically, to find pulsars, astronomers seek the distinctive repetitive signals that these astonishing objects leave in the data of the radio telescopes. The method is effective. Most of the time. Because it tends to fail to detect out-of-the-ordinary pulsars. Pulsars that are too fast or too slow. But also those whose ” pulse » is dispersed.

Still many pulsars to discover

To detect this type of pulsar, the researchers imagined that they could rely on another property of pulsars. Their beams, in fact, can be highly circularly polarized. Understand that the electric field of their light waves adopts a circular motion as the waves travel through space. And such signals are rare.

But precisely, theAustralian Square Kilometer Array Pathfinderthe Australian Square Kilometer (Askap) Radio Telescope Array, has sorts of ” sunglasses » allowing him to capture this lightpolarized. And it was a student who finally spotted, in the data from the instrument, a circularly polarized object, in a place where there was no known pulsar.

Observations of the region using other telescopes made it possible to eliminate all the assumptions. And the MeerKAT radio telescope – also equipped with the famous ” glasses of sun » – from the South African Radio Astronomy Observatory confirmed it. It is indeed a pulsar that Askap has thus detected. A pulsar ten times brighter than any other pulsar detected so far outside the Milky Wayat about 160,000light yearsof our Earth. Maybe even just thebrighternever observed.

Thanks to this new technique, astronomers now hope to discover other extragalactic pulsars. And why not, pulsars located beyond the Large Magellanic Cloud. Observations that will help them better understand the processes that are still hidden behind these extreme objects.