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At the heart of a galaxy more than 570 million light years away, energy travels through space so steadily that astrophysicists have dubbed the galaxy Old Faithful, after the famous predictable geyser of Yellowstone National Park. This is the first time that such regular and frequent eruptions have been spotted emanating from the core of a distant galaxy.
About once every 114 days, flares emerge from the center of the galaxy ESO 253-3 (the events took place almost 600 million years ago, but scientists are now seeing them for the first time due to of how far the light of the galaxy must travel. Earth).
Researchers recently counted 17 such explosions spanning about six years. Flares have been spotted by instruments on the ground and in space, including NASA space telescopes such as the Transiting Exoplanet Survey Satellite (TESS) and the Neil Gehrels Swift Observatory, representatives of NASA. said in a press release.
Related: 10 huge black hole discoveries from 2020
The culprit behind the eruptions is likely the galaxy’s supermassive black hole, a cosmic giant about 20 times the size of the black hole known as Sagittarius A * (Sgr A *) at the center of the Milky Way galaxy. . To put this in perspective, Sgr A * is about 23.6 million kilometers in diameter and is about 4 million times the mass of the sun.
As the ESO 253-3’s huge black hole snacks on a nearby star, the star’s siphoned gases collide with the black hole’s debris disk to produce brilliant flares, according to a study presented on Jan. 12 at the 237th meeting of the American Astronomical Society, held virtually this year. The researchers also described their discovery in a study that has not yet been peer reviewed, published online September 7, 2020 in the Preprinted Database. arXiv.
On November 14, 2014, the first of these eruptions was detected – and considered a supernova – by researchers at the All-Sky Automated Survey for Supernovae (ASSAS-SN), a project managed by the Ohio Department of Astronomy State University. which integrates a network of 24 telescopes around the world, according to the ASSAS-SN project website.
However, in 2020, scientists analyzed the last six years of ASSAS-SN data and identified other eruptions emerging from the galaxy at regular intervals, about 114 days apart. Based on these observations, scientists were able to predict when subsequent explosions would be seen in 2020: May 17, September 6, and December 26. They confirmed these events with observations at multiple wavelengths from the ground and in space.
Scientists also compared data from ASSAS-SN on past eruptions with sky surveys from TESS, which provided more information than ASSAS-SN on the activity of specific eruptions. For example, TESS captured “a very complete image” of a flare from November 8, 2018, recording images as it brightened and faded for about five days, “but because of the way the mission imagine the sky, it cannot observe all, ”study co-author Patrick Vallely, a National Science Foundation graduate researcher at Ohio State University, said in a press release.
“ASAS-SN collects less detail on individual explosions, but provides a longer baseline, which was crucial in this case,” Vallely said. “The two investigations complement each other.”
The most likely explanation for recurring flares is a phenomenon known as tidal disturbance, in which a star’s orbit carries it so close to a black hole that pieces of the star are torn off and sucked into the accretion disk – a diffuse band of dust, gas and debris circling around the black hole. Usually such events end with the complete destruction of the star. In the case of ESO 253-3, a massive star’s orbit can bring it close enough to the black hole for the star to lose some of its material, generating a flare. But then the star breaks off and escapes. The cycle repeats itself whenever the star gets close enough to the black hole to feel its inexorable pull, the researchers said in the study.
ESO 253-3’s regular and predictable emissions have provided a rare window into the behavior of black holes and could help scientists better understand how these mysterious cosmic objects grow and change, according to the study.
“It’s really exciting, because we’ve seen black holes do a lot of things, but we’ve never seen them do anything like that – cause this regular eruption of light – before,” Vallely said in the statement. “It’s like an extra-galactic Old Faithful.”
Originally posted on Live Science.
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