Radio astronomers have detected jets of hot gas blasted out by a black hole in the galaxy at the heart of the Phoenix Galaxy Cluster, situated 5.9 billion light-years away in the constellation Phoenix. This is a crucial outcome for understanding the coevolution of galaxies, gas, and black holes in galaxy clusters.
Galaxies are not distributed randomly in area. Through mutual gravitational tourist attraction, galaxies gather together to form collections known as clusters. The area between galaxies is not totally empty. There is extremely water down gas throughout a cluster which can be spotted by X-ray observations.
If this intra-cluster gas cooled, it would condense under its own gravity to form stars at the center of the cluster. Cooled gas and stars are not typically observed in the hearts of nearby clusters, showing that some mechanism must be heating up the intra-cluster gas and avoiding star development. One possible prospect for the heat source is jets of high-speed gas sped up by a super-massive great void in the main galaxy.
The Phoenix Cluster is uncommon because it does show indications of dense cooled gas and huge star development around the central galaxy. This raises the concern, “does the central galaxy have black hole jets as well?”
A team led by Takaya Akahori at the National Astronomical Observatory of Japan utilized the Australia Telescope Compact Variety (ATCA) to search for black hole jets in the Phoenix Galaxy Cluster with the greatest resolution to date. They detected matching structures extending out from opposite sides of the main galaxy. Comparing to observations of the region drawn from the Chandra X-ray Observatory archive information shows that the structures spotted by ATCA represent cavities of less thick gas, indicating that they are a pair of bipolar jets produced by a great void in the galaxy. The team found the first example, in which intra-cluster gas cooling and black hole jets exist together, in the distant Universe.
More details of the galaxy and jets could be elucidated through higher-resolution observations with next generation observational centers, such as the Square Kilometre Array scheduled to begin observations in the late 2020 s.