September 12, 2019 , European Space Agency

Black hole at the center of a distant galaxy periodically flares up. Credit: European Space Agency

ESA’s X-ray space telescope XMM-Newton has detected never-before-seen periodic flares of X-ray radiation coming from a distant galaxy that could help explain some enigmatic behaviours of active black holes.

XMM-Newton, the most powerful X-ray observatory, discovered some mysterious flashes from the active black hole at the core of the galaxy GSN 069, about 250 million light years away. On 24 December 2018, the source was seen to suddenly increase its brightness by up to a factor 100, then dimmed back to its normal levels within one hour and lit up again nine hours later.

“It was completely unexpected,” says Giovanni Miniutti, of the Centro de Astrobiología in Madrid, Spain, lead author of a new paper published in the journal Nature today.

“Giant black holes regularly flicker like a candle but the rapid, repeating changes seen in GSN 069 from December onwards are something completely new.”

Further observations, performed with XMM-Newton as well as NASA’s Chandra X-ray observatory in the following couple of months, confirmed that the distant black hole was still keeping the tempo, emitting nearly periodic bursts of X-rays every nine hours. The researchers are calling the new phenomenon ‘quasi-periodic eruptions,” or QPEs.

“The X-ray emission comes from material that is being accreted into the black hole and heats up in the process,” explains Giovanni.

“There are various mechanisms in the accretion disc that could give rise to this type of quasi-periodic signal, potentially linked to instabilities in the accretion flow close to the central black hole.

“Alternatively, the eruptions could be due to the interaction of the disc material with a second body-another black hole or perhaps the remnant of a star previously disrupted by the black hole.”

Optical and X-ray view. Credit: European Space Agency

Although never before observed, Giovanni and colleagues think periodic flares like these might actually be quite common in the Universe.

It is possible that the phenomenon had not been identified before because most black holes at the cores of distant galaxies, with masses millions to billions of times the mass of our Sun, are much larger than the one in GSN 069, which is only about 400 000 times more massive than our Sun.

The bigger and more massive the black hole, the slower the fluctuations in brightness it can display, so a typical supermassive black …read more

Source:: Daily Times

      

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Unexpected periodic flares may shed light on black hole accretion

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