US, WASHINGTON (ORDO NEWS) — New observations have confirmed that since 2014, the activity of a supermassive black hole in the center of our galaxy has been increasing. The results of the study are described in an article accepted for publication in the journal Astronomy & Astrophysics. A preprint of the article is available at the arXiv.org online library.
Sagittarius A * – a supermassive black hole located 26 thousand light-years from us, in the center of the Milky Way – is not particularly active in comparison with similar objects in the centers of many other galaxies, which are actively fed by material from the surrounding space.
Nevertheless, the brightness of the center of our Galaxy daily fluctuates slightly in the electromagnetic spectrum. And since 2014, the radiation of Sagittarius A * is gaining strength.
The surroundings of this black hole emit more and more powerful flashes, which become brighter over time.
In 2017, the Belgian astrophysicist Emmanuelle Mossoux from the University of Liège and the French astronomer Nicolas Grosso from the Strasbourg Astronomical Observatory published a report on the 16-year observation of the black hole Sagittarius A * with XMM-Newton, Chandra and Swift space telescopes. During this period, they recorded a total of 107 outbreaks, the intensity of which since 2014 began to increase.
The article noted that since August 31, 2014 the number of bright X-ray flares has tripled, and the number of weak flashes since August 2013, on the contrary, has decreased.
Now, these same scientists, together with their colleagues, have prepared a report for the period from 2016 to 2018, from which it is clear that our galactic center is becoming increasingly restless. During this period, astronomers observed 14 new outbreaks, which, together with previous data, makes a total of 121 outbreaks for the period from 1999 to 2018.
The authors also cite the results of a preliminary analysis of data for 2019, during which the Swift telescope recorded as many as four bright flashes – an unprecedented amount in such a short period. Data from the XMM-Newton and Chandra telescopes for 2019 is still being prepared for publication.
After they are published, according to scientists, it will be possible to draw preliminary conclusions about the causes of increased x-ray activity – these may be episodes of accretion, tidal activity or the influence of passing asteroids.
Repeated analysis did not confirm the decrease in the number of weak flares, which was mentioned in the 2017 article, they remained quite stable throughout the entire observation period. But strong flashes became much more.
Although the study deals only with the X-ray wavelength range, the authors note that in the near infrared range last year, a black hole was 75 times its normal brightness. The authors write that this is “unprecedented compared to historical data.”
Scientists hope that observations at other wavelengths will help to find out what causes the black hole in the center of our Galaxy to show incomprehensible activity.
“Since 2014, the activity of Sagittarius A * has been growing at several wavelengths,” the astronomers summarized in the article. “Additional observations will confirm this unprecedented activity of a supermassive black hole and find out its source.”
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