Published: Wed, August 14, 2019
Research | By Raquel Erickson

Astronomers Spot Unprecedented Flashes From Our Galaxy's Black Hole

Astronomers Spot Unprecedented Flashes From Our Galaxy's Black Hole

The team published their findings regarding the Milky Way's supermassive black hole in The Astrophysical Journal Letters.

Our black hole, Sagittarius A*, is not known to typically show such oscillating behaviour over long periods of time, let alone a mere couple of days. Suddenly, the Sagittarius A* grew 75 times brighter, before going back to its normal brightness shortly.

Do and his team took observations of the galactic centre using the WM Keck Observatory in Hawaii over four nights earlier this year. "I knew nearly right away there was probably something interesting going on with the black hole", the report said quoting Do. With every microscopic aspect analyzed and a rough pattern established, astronomers were taken aback by the recent behaviour of a black hole very close to home - our very own * a href="https://en.wikipedia.org/wiki/Sagittarius_A*" *Sagittarius A*. Normally, the brightness of Sgr A* flickers a bit like a candle, varying from minutes to hours. The black hole is well-known to scientists, and was one of the subjects of our first ever efforts to image the cosmic beasts, but its still throwing up new mysteries all the time. Another cause could be a change to its accretion state-how the black hole is drawing matter inwards.

An attempt to prove Einstein's hallmark theory of gravity revealed something even freakier: an unprecedented flash from the black hole at the centre of our galaxy. The team points to two possibilities.

Another explanation is associated with the star S0-2, which is on an elliptical orbit around the black hole, and last year approached her at 17 light years. One is G2, an object thought to be a gas cloud that approached within 36 light-hours of Sgr A* in 2014.

But - have a look at the timelapse again. However, the objects and material close to them do-and changes to the black hole can excite matter nearby, allowing scientists to detect changes taking place. It made its closest approach yet a year ago, coming within 17 light hours of the event horizon.


Do told Science Alert, 'One of the possibilities, is that the star S0-2, when it passed close to the black hole past year, changed the way gas flows into the black hole, and so more gas is falling on it, leading it to become more variable'.

However, the only way to find out is by having more data, which is being collected across a larger range of wavelengths.

Currently, scientists are gathering as much information as they can.

There are only a few weeks left before the black hole will be visible from the Keck Observatory.

Do told ScienceAlert they are now waiting for data from other telescopes, including NASA's Spitzer and Chandra, to better understand what might have happened with Sagittarius A*.

"I'm eagerly awaiting their results", Do said. The study is now available on a preprint website arXiv.

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