Astronomers utilizing NASA’s Chandra X-ray Observatory have discovered a quartet of pronounced X-ray cavities in RBS 797, a cluster of galaxies situated about 3.9 billion light-years away within the constellation of Draco. This suggests there’s a pair of carefully orbiting supermassive black holes, each of which erupted and generated jets at about the identical time. If confirmed, these black holes could be among the many closest pair ever found, with a separation of about 250 light-years.
Four monumental cavities have been discovered on the heart of the RBS 797 galaxy cluster utilizing Chandra. Image credit score: NASA / CXC / University of Bologna / F. Ubertosi / STScl / M. Calzadilla / NSF / NRAO / ALMA.
“We think we know what a pair of cavities represents, but what is going on when a galaxy cluster has two pairs in very different directions?” mentioned Dr. Francesco Ubertosi, an astronomer on the University of Bologna.
Astronomers beforehand noticed a pair of cavities within the east-west course in RBS 797, however the pair within the north-south course was solely detected in a brand new, for much longer Chandra statement.
The deeper picture makes use of nearly 5 days of Chandra observing time, in comparison with about 14 hours for the unique statement.
NSF’s Karl G. Jansky Very Large Array had already noticed proof for 2 pairs of jets, which line up with the cavities.
“Our best idea is that one pair of supermassive black holes has led to a pair of a pair of cavities,” mentioned Dr. Myriam Gitti, additionally from the University of Bologna.
“While we think supermassive black holes can form binary systems, it is extremely rare that both of them are observed in an active phase — in this sense the discovery of two close active black holes inflating cavities in RBS 797 is extraordinary.”
Indeed, beforehand a radio statement with the European VLBI Network found two radio level sources separated by solely about 250 light-years in RBS 797.
If each sources are supermassive black holes, they’re among the many closest pair ever detected.
The two black holes ought to proceed to spiral towards one another, producing big quantities of gravitational waves, and finally merge.
According to the astronomers, there may be one other doable rationalization for the 4 cavities seen in RBS 797.
“This scenario involves only one supermassive black hole — with jets that somehow manage to flip around in direction quite quickly,” they mentioned.
Their evaluation of the Chandra information exhibits that the age distinction for the east-west and north-south cavities is lower than 10 million years.
“If there is only one black hole responsible for these four cavities, then we will have to trace the history of its activity,” mentioned Dr. Fabrizio Brighenti, additionally from the University of Bologna.
“Key aspects are how the jets’ orientation changed quickly, and whether this is related to the galaxy cluster environment or to the physics of the black hole itself — or even a combination of both.”
The outcomes had been printed within the Astrophysical Journal Letters.
_____
F. Ubertosi et al. 2021. The Deepest Chandra View of RBS 797: Evidence for Two Pairs of Equidistant X-ray Cavities. ApJL 923, L25; doi: 10.3847/2041-8213/ac374c
