Our galaxy’s supermassive black hole is acting weirder than normal

In the late 1990s and early 2000s, studies of objects near Sagittarius A* demonstrated it had a strong gravity explained best by a supermassive black hole.

As per Gizmodo, the team of researchers recently observed a flash of infrared radiation that was brighter than had ever been observed in the 20 years of studying the black hole. Soon, they are going to start reviewing observations of the supermassive black hole in the Milky Way made by multiple instruments over the last few months, including the Spitzer, Chandra, Swift, and ALMA telescopes.

Tuan Do, from UCLA, and colleagues spent four night observing Sagittarius A a rel="nofollow" href="https://www.sciencealert.com/our-galaxy-s-supermassive-black-hole-just-mysteriously-got-really-really-bright" target="_blank" *ScienceAlert reports.

What makes it remarkable is that Sagittarius A* is normally relatively dim.

The galaxy, Holm 15A, sits around 700 million light-years away, making it somewhat hard to study in detail, but what scientists know for sure is that the black hole in its heart is the largest ever discovered.

The researchers observed the black hole for four nights in May using an infrared camera at the Keck Observatory in Hawaii. At its peak, Sagittarius A* was 75 times brighter than usual in infrared.

In fact, this was the focus of the scientist's initial readings - they were testing Einstein's theory of general relativity by seeing if the black hole would warp the approaching star's light. Currently, we do not possess the technology necessary to detect radiation emitted directly by black holes, but we can observe the effects its gravitational force has on the surrounding objects, causing huge friction, which produces radiation. It's thought to be at least twice as large as the previous largest black hole detected by scientists. The team points to two possibilities. In fact, researchers believe the black hole in Holm 15A is at least 10,000 times as massive as our home galaxy's black hole. There were no cosmic fireworks at the time, but we could be seeing a delayed reaction.

But - have a look at the timelapse again. While the supermassive black hole itself isn't visible, its so-called electromagnetic counterpart can be tracked.

A star called S0-2 is approaching the black hole.

The only way to find out is having more data. "Additional multi-wavelength observations will be necessary to both monitor Sagittarius A* for potential state changes and to constrain the physical processes responsible for its current variability".

The Galactic centre of the Milky Way is dominated by one resident, the supermassive black hole known as Sagittarius A* (Sgr A*). Their data could reveal different aspects of the physics of the change in brightness, and help us understand what Sgr A* is up to.

The paper has been accepted into The Astrophysical Journal Letters, and is available on arXiv.