Magnetars were caught in flashes of “death rays” – the brightest phenomena in the Universe

Science is still in the dark as it searches for the source of fast radio bursts (FRBs), first discovered in 2007. In a few milliseconds, something from the depths of the Universe sends out a radio pulse with a power comparable to three days of solar radiation. Scientists have thoughts about the origin of the bursts and one of the hypotheses has been well confirmed.

Image source: Robert Lea / space.com

In the journal Nature, a group of astronomers published a paper in which they reported the discovery of a faint source of a radio signal from the supposed space of one of the previous bursts: FRB 20201124A at a distance of about 1.3 billion light years from us. The Very Large Array radio telescope in the USA helped detect the weak radio signal. The radio signal comes from a faintly luminous nebula at the suspected source of a fast radio burst.

The authors of the study explained that the detected very weak radio emission is related to the emission ranges of pulses of fast radio bursts. This allowed scientists to create their own “nebula model”, in the depths of which fast radio bursts are born. In particular, the proposed model predicts that the radio emission of space is created by a bubble of plasma (ionized gas) with the “engine” of the process in the center of the bubble. The “engine” is responsible for the flares, and the flares themselves inflate a bubble of gas (plasma) around it.

«The discovery allows us to attribute the origin of fast radio bursts to the remnants of massive stars, scientists conclude. “Our discovery of the continuous emission associated with a particular FRB allows us to better understand their source environment, implying that the central drive producing the flares must also be capable of inflating the plasma bubble with a wind [of charged particles].”

«The best candidate to explain these properties so far is a magnetar, an extremely magnetized neutron star,” the researchers conclude.

Magnetars are a special case of neutron stars – the cores of once giant dead stars 8 or more times larger than the Sun, compressed to just 19 km. One teaspoon of neutron star matter would weigh 1 billion tons. By reducing the diameter of the object, the speed of neutron stars can reach 700 rps. Also, the physical compression of the core leads to an unimaginable increase in the magnetic field.

These are very valuable objects for studying physics under extreme conditions, which we will never be able to replicate in laboratories on Earth. Moreover, studying neutron stars could open the way to new physics. This is why it is so important to understand or link fast radio bursts to magnetars or other sources, if any. And they can be! Some fast radio bursts repeat themselves – this is very rare, but it does happen. Scientists do not rule out that repeating FRBs and single ones may have different origins.

The new discovery allows us to take another look at the likely sources of fast radio bursts to obtain previously missed features of the behavior of space in the radio frequency range in the event area. Bubbles of dead stars turned out to be a valuable trace leading to magnetars.