At the center of a galaxy more than 570 million light years from Earth, energy flares up with surprising regularity. Astrophysicists are the first to observe such regular and frequent flares emanating from the core of a distant galaxy.
Flares appear at the center of ESO 253-3 approximately every 114 days. It is worth noting that the galaxy is located almost 600 million light years from Earth, which means that these outbursts also occurred almost 600 million years ago. And only now is the light about a distant galaxy available to scientists. It took him 570 million years to reach Earth.
In total, astrophysicists have counted 17 such flares over six years of observation. They were discovered by instruments both on Earth and in space. The telescope for the discovery of exoplanets by the transit method (TESS) and Swift, an orbiting observatory, a joint project of the USA, Italy and the UK, were responsible for collecting data in space.
The flares are likely caused by a supermassive black hole at the center of the galaxy. This cosmic giant is about 20 times the size of the Sagittarius A * (Sgr A *) black hole at the center of the Milky Way galaxy. For comparison: Sgr A * has a diameter of about 23.6 million km and about 4 million times the mass of the Sun.
The first of 17 flares was discovered on November 14, 2014 and was considered a supernova.
However, in 2020, scientists analyzed data from the All-Sky Automated Survey for Supernovae (ASSAS-SN) over the past six years and identified more flares coming out of the galaxy at regular intervals, with a difference of about 114 days. Based on these observations, scientists successfully predicted when subsequent outbreaks would occur in 2020: May 17, September 6, and December 26. They confirmed these events by observations from the Earth and in space.
The most likely explanation for recurring flares is a tidal discontinuity, in which the star’s orbit brings it so close to the black hole that parts of the star break away and are sucked into the accretion disk – a diffuse band of dust, gas, and debris that orbits the black hole. Usually such events end with the complete destruction of the star. In the case of ESO 253-3, the orbit of a massive star could bring it close enough to the black hole for the star to lose some of its material, triggering a flare. But then the star slips away and runs away. The cycle repeats every time the star passes close enough to the black hole.