Astronomers trace emissions from repeating fast radio burst to plasma bubble | Science News

The researchers have constrained the nature of the engine driving mysterious repeating fast radio bursts.

Illustration of a plasma bubble around a magnetar. (Image Credit: US NSF/AUI/NSF NRAO S. Dagnello).

New Delhi: Fast Radio Bursts (FRBs) are among the most powerful cosmic explosions, releasing an immense amount of energy in radio frequencies in pulses that last milliseconds. Scientists do not understand the sources that they originate from, and as such FRBs are considered to be a mysterious phenomenon. Only a handful of these FRBs are known to be persistent, and associated with persistent background emissions. One of the first repeating FRBs discovered is designated as FRB20201124A. An international team of scientists have now identified the engine driving the persistent emissions associated with the repeated FRB, which is a magnetar surrounded by a planetary nebula, or a roughly spherical bubble of hot gas.

The researchers from Italy, China, USA, Spain and Germany have recorded the weakest ever persistent radio emission associated with an FRB. The plasma bubble is located at a distance of about 1.3 billion lightyears from the Earth. The observations were conducted by the Very large Array in the United States. There are around 800 known FRBs, out of which only around 10 per cent are repeating FRBs. The researchers had previously identified the host galaxy of the FRB, but could not resolve the position sufficiently to associate the persistent radio emissions and the FRB. The team was able to observe the environment around the FRB in unprecedented detail with the new dedicated campaign.

Magnetar or X-ray binary system is source of plasma bubble

The researchers were able to determine that either a highly magnetised neutron star, the remnant core of a dead star, or an X-ray binary system is at the heart of the plasma bubble, is responsible for the energetic stellar winds that produced the plasma bubble. A paper describing the findings has been published in Nature. Lead author of the paper, Gabriele Bruni says, “We were able to demonstrate through observations that the persistent emission observed along with some fast radio bursts behaves as expected from the nebular emission model, i.e. a ‘bubble’ of ionized gas that surrounds the central engine. In particular, through radio observations of one of the bursts that is nearest to us, we were able to measure the weak persistent emission coming from the same location as the FRB, extending the radio flux range explored so far for these objects by two orders of magnitude.”

 

 

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