In the weird, strange or unexplained stellar objects department, Fast Radio Bursts are now at the top of the list. Magnetars can be the possible sources of these emissions, and the first direct geometric measurement of the distance between one of them and the Earth is the first step in that direction.
Magnetars are corpses of supermassive stars that exploded in supernovae – neutron stars with gigantic magnetic fields (so far, the largest in the Universe). As they emit strong bursts of X-rays and gamma rays, they have become natural candidates for sources of FRBs. And it was for one of them, the XTE J1810-197, that the Very Long Baseline Array (VLBA) antennas turned.
From January to November 2019 and then, between March and April of this year, astronomers regularly observed the magnetar discovered in 2003, collecting data from opposite sides of the Earth’s orbit around the Sun. With that, they managed to register a slight change in its position in relation to more distant background objects – the parallax effect (the difference in the apparent position of an object seen by observers in different locations).
Power to issue FRBs
“Our measurement showed that this magnetar is among the closest known, about 8.1 thousand light years. In the future, it will be the main target of studies, ”said astronomer Hao Ding, from Swinburne University of Technology in Australia.
The clue that led astronomers to consider magnetars as sources of FRBs came from the observation of another of these dead stars, the SGR 1935 + 2154. On April 28, a brief radio explosion was recorded – the largest ever recorded in our galaxy.
On the eve of the event, radio telescopes around the planet detected an increase in magnetar activity. Thus, the next day, when the blast was captured on Earth, the Canadian Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope captured a radio explosion so intense that it was not possible to quantify it at the time.