The Supermassive Black Hole at the centre of our Milky Way is becoming more active.
The supermassive black hole at the centre of the , isn't exactly rowdy. It's not classified as an active galactic nucleus one of those galactic cores that glow exceedingly brightly as they feast on copious amounts of material from the surrounding space.
However, the brightness of our galaxy's centre does fluctuate a little across the electromagnetic spectrum on a daily basis.
The paper has been accepted in the journal Astronomy & Astrophysics, and is already available on arXiv while it undergoes the peer review process.
The earlier work co-authored by Mossoux studied X-ray data on Sgr A* from the XMM-Newton, Chandra and Swift observatories collected between 1999 and 2015. They detected 107 flares in total. Not only were the brightest X-ray flares increasing after August 2014, the faintest ones had decreased from August 2013.
Then, they analysed all the flares, using the previous methods, and revised methods to determine the flare rate and distribution. These found that one of the earlier conclusions was incorrect - there was no decrease in the rate of faint flares
"However, this did not change our global result a change in flaring rate is found for the brightest and most energetic flares at the same date as was found in the previous section," the researchers wrote in their paper.
The team analysing the near-infrared observations had a dataset of 133 nights from 2003 and last year, they found three nights on which Sgr A* near-infrared activity was elevated. They said in their paper that this was "unprecedented compared to the historical data."
Mossoux and her team have also checked to see if the 2019 activity is consistent with their recent findings. They analysed the Swift data from 2019, and found four bright flares, the largest number ever observed in a single campaign, confirming that the black hole is not settling down.
Additionally, XMM Newton and Chandra data from 2019 - due for release this year - could reveal even more about the peculiar X-ray activity, and what might be causing it - whether it's accretion, or something else, such as the tidal disruption of passing asteroids.
Observations across other wavelengths could reveal more information too. Continued observations in the near-infrared, and radio wave observations, could help us figure out what's making Sgr A* stir.
"Additional multiwavelength data are required to conclude on the persistence of this increase and to obtain clues on the source of this unprecedented activity of the supermassive black hole."
